Home

Electronics Technician Volume 3 - San Francisco Maritime National

Contents

1. CA A UJ No CTO gt UA pk 2 E Table 1 4 Logarithms E LOG 10 1 0000 Ee a oC 0 LOG 4 0 6021 LOG 20 1 3010 TAR E N TANANA 1 A771 LY 9 U 02Z7U LAAJ 1 4 1 LOG 6 0 7782 LOG 40 1 6021 LOG 7 0 8451 LOG 50 1 6990 PEN E RUOLO RE C QN pmi J 3 oo KO receiver s sensitivity drops to 107 dBm Since a loss of The primary advantage of using a transceiver 3 dB reduces the sensitivity by 1 2 the input signal will rather than a separate transmitter and receiver is cost have to be twice as large to be detected In a transceiver many of the components can be shared during both transmit and receive operations Another TRANSCEIVERS advantage is that transceivers can be tuned more easily than separate units A transceiver is a unit usually enclosed in a single case that combines a transmitter and receiver using a A disadvantage of using a transceiver is that common frequency control Transceivers are used ex while duplex operation is not possible with most trans tensively in two way radio communications at all fre ceivers communication must sometimes be carried quencies and in all modes out on two different frequencies Although this is a 1 11 problem with most transceivers some do have provi sions for separate transmit and receive operations al lo
2. CARRIER nmu my amd GENERATOR V VU VUUYU 229 gt lt lt lt 4 ETV30006 Figure 1 6 SSB transmitter block diagram Selection Selection is the ability to distinguish a particular station s frequency from all other station frequencies appearing at the antenna Detection Detection is the extraction of the modulation from an rf signal Circuits that perform this function are called detectors Different forms of modulation require different detector circuits Reproduction Reproduction 1s the action of converting the elec trical signals to sound waves that can be interpreted by the ear RECEIVER CHARACTERISTICS Understanding receiver characteristics is manda tory in determining operational condition and for com paring receivers Important receiver characteristics are sensitivity noise selectivity and fidelity Y Sensitivity Sensitivity is a measure of receiver s ability to re produce very weak signals The weaker the signal that can be applied and still produce a certain signal to noise S N ratio the better that receiver s sensitivity rating Usually sensitivity is specified as the signal strength in microvolts necessary to cause a S N ratio of 10 decibels or 3 16 1 Noise receivers generate noise Noise is the limiting factor on the minimum usable signal that the receiver can process and still produce a usable output Ex pressed in decibe
3. H Rt MS LSN PRE PHA CC2 EOT NOIS DATA 5 DATA 12 NCT 7 0 re m m 38NP0203 S S Figure 5 10 The LMS 11 Net Display in Summarize Mode NCS The NCS field allows the operator to designate the PU number of the NCS When a number is not entered in this field the default address of 77 is used It will also be used as the PU number in the polling display of the status area and in the PU field of the Net Display PU The PU field is used by the operator to designate the PU whose recurring transmission is used to define a cycle The PU field works with the SUMMARIZE field SIDEBAND The SIDEBAND field allows the operator to designate which sideband USB LSB or DIV is used for the information displayed SUMMARIZE The SUMMARIZE field enables the operator to designate the number of cycles over which the summary is computed A cycle is defined as the recurring transmission from the designated PU The data is tabulated after the 5 13 specified number of transmissions are received from the designated PU or after 200 transmissions are received by any station whichever occurs first The SUMMARIZE field is also used to enable the PU History mode The PU History mode is entered when the operator enters a zero in the summary field When the PU History mode is enabled by the operator the word HISTORY is added to the Net Display title
4. I nanza a wv 3 B ET V30046 vi uss __ A 92 HS 2aui om 354 81872 VF 35 43040934 JI HavaoO1dAUD j _nesvecray 1 OISIG OVW waondowdsy 02 J NV M3OHOO3M NOSS3OO0Md 9N 9 A vz9 11 OW c peur gaa reo ea 11 omo 1 pL Sune B3GHOO3H _ i xS MO i GEO 2351 Eorum rr mque AER sco Lope Mii ie x TTT ET pi i sc9 w23s1 avi Hh Werno sSonaoses v JUOVIN E AAA IOLL dnOM5 550400258 SW3LSAS Sd VAVO ONILO3NNOO 35 31084 ONIOQVANSINI qo Se G9 OSn NY IVININOGZ L zm QHVOS8A3 SW31SAS ONIOVSYSILN 3 12 terrestrial wireline systems with the SATCOM Defense Satellite Communications Systems and alternate hf systems This system extends shore communications seaward and gives commands at sea the same Secure Voice telephone communications currently provided to the worldwide shore es tablishment The RWI provides interconnection among the Secure Voice Improvement Program SVIP channels STU III units a RED telephone bus the Advanced Narrowband Digital Voice Terminal SATCOM radio terminals uhf
5. 80 OR AN VRC 46 The transmitter transfer switchboard allows TRANSCEIVER operators to select the proper transmitter for the selected frequency The AN URT 23 transmitter m receives its input from the switchboard and changes TRANSMITTER RECEIVER TRANSFER EE TRANSFER the signal to a modulated rf signal that 15 fed to the SWITCHBOARD CONTROL SWITCHBOARD AN SRA 34 56 57 58 or AN URA 38 antenna coupler The antenna coupler matches the output impedance of the transmitter to the input impedance of the antenna Antenna couplers also allow more than one transmitter to be connected to the same antenna as long as certain conditions are met When the signal reaches the antenna it is radiated into the atmosphere Shipboard Hf Receive A typical shipboard hf receive system is shown in A transmitted signal similar to the one previously discussed is received by the antenna and converted from electromagnetic energy to electrical energy The signal is fed to an antenna patch panel where it can be distributed to any number of receivers In figure 2 6 a receiver R 1051 URR R 2368 URR or R 1903 URR converts the rf signal into either a teletype signal fsk or voice The receiver output is then fed to the SB 973 SRR receiver transfer switchboard The teletype signal from the switchboard follows the same path used by the low frequency signal we discussed earlier Identical pieces of equipment are used The voice signal from
6. SINGLE CHANNEL TELETYPE TU be a c gt 0 PUNCH eee ETV30042 Figure 3 4 NAVMACS V communications interface VINVG Uou uijs sqns S VINAVN SXII12 SINAWAYINDAY WHOdlV d OL 9NIOMOOOV SW3ISAS 3e3HL JO HLM OSN 6 A svi No v OSn 6 A EPL NO SNIISDG HLM 530 31 WaISAS BS aasva A OZ 94An NV pe Sn 6 A PI NO IHL 3snind IHL NI OSN Z A EFI NO SNILSIXS 3HL HLM AINO 39vdi331NI SQdW ONY 2 2 3s SUCI 067 6 A amp 1 NO 3H1 OL TIM 080 42 amp NO ONY OSn A amp L NO 3HL O gt pues So ee AStHSNINY mondo ix assw pus oa LA i po XL Een onis rou N on x Z A 9 051 uum uem ow A ZZ HSN NV 3dv1 9 vw pp l N 5 A 29 11 ma r A v9 DSn NV dosi M30NOOSM 9 2351 9 L See 2351 o a oss 1 ixl OLIVOINOQWiOO CUN o NP POR RE J 4 2 aee osnsv
7. stop code XS received 1 The DTS compares the next two frames received with the own station address 2 The DTS resets all I O 6 3 The DTS sends the next two frames received to the CDS computer 4 The DTS sends the prepare to transmit data interrupt to the computer 18 When the DTS recognizes own station address it transmits which of the following signals LIPS Prepare to transmit interrupt 2 The first frame of the preamble 3 The phase reference frame 4 Input data request At the start of a transmit cycle the output data request is first set active during which of the following frames 1 The first frame of the preamble 2 The first frame of the start code 3 The phase reference frame 4 The second frame of the start code Which of the following events takes place when the CDS computer does not answer an ODR from the DTS within the Specified time limit 1 The DTS generates the stop code 24 The DTS hangs up 3 The computer generates an external function to clear the DTS 4 The computer sends a stop code to the DTS Which of the following events occur if an interrogated picket station does not answer an initial interrogations from the NCS within 15 frame intervals 1 NCS interrogates the next station 2 NCS waits another 15 frame intervals 3 Link 11 network hangs up 4 NCS retransmits the interrogation to the unit that did not reply ASSIGNMENT 4
8. Frequency used Frequency quality Equipment used radio trunk line computer crypto etc Start and stop time of the POFA The printout will contain a summary of the activity that includes the time in minutes and seconds that the station was on the air the total number of words transmitted the total number of words received and the total number of words with errors This information can be used to calculate the link quality factor To calculate the link quality factor divide the number of words received by the number of words transmitted When the quotient is greater than 95 percent but less than 100 percent consider the POFA successful Next compute the receive error factor Ideally the POFA should run with zero errors Since the multi station POFA is transmitted atmospheric interference ship s position antenna location and EMI are just a few of the things that can induce errors in a radio signal Determine the receive error factor by dividing the number of words with errors by the number of words received When the receive error factor is less than 1 percent consider the POFA successful When the printout indicates that data was received from an unrecognized station UNREC STA the technician should check the number of words received The multi station POFA transmit buffer consists of 230 words One buffer of 230 words from an unrecognized station is acceptable and generally does not indicat
9. IPA PA AMPLIFIER a en ANTENNA LY ICW OR eR FSK TRANSMISSION ETV30014 Figure 2 2 VIf radio transmitting station block diagram URR R389 Figure 2 3 illustrates a typical vlf receiving system using the AN BRR 3 receiver Most surface ships no longer receive vlf broadcasts However you will probably find one of these receivers mounted somewhere in your message center or radio room LOW FREQUENCY COMMUNICATIONS The low frequency If band occupies a very small portion of the radio frequency spectrum However the Navy s requirement to provide the best possible communications to the fleet requires operation on all frequency bands The low frequency band is used for long range direction finding encrypted medium and long range communications and aeronautical radio navigation Lf Transmit The low frequency transmitter is a part of the Fleet Multichannel Broadcast System operating at high Ll d K ANTENNA GROUP 7 1 o LOOP ANTENNA OR AN BRA 8 XN 1 GFM AT 317 BRR WHIP GFM ANTENNA GFM HEADSET GFM 105 115 125V 50 60 CPS SUPPLY 120 WATTS RADIO RECEIVING SET TELEPRINTER GFM Figure 2 3 Typical vif receiving system power over long distances It provides eight channels of frequency division multiplex rtty traffic on each transmission The AN FRT 72 transmitter 15 designed specifically for this purpose It pro
10. Prepare to transmit Prepare to receive of receive If you receive interrupts in any other order such as two consecutive prepare to transmit interrupts or an end of receive before the prepare to receive an error condition exists The parity should always equal zero As you learned in the previous chapter the parity or error detection status bits indicates an error has been detected in the received data When errors are detected they are listed in the bit by bit section of the printout Even if the printout indicates a few random bit errors this condition should not be ignored Random bit errors can be caused by several areas in the system including the CDS computer the data switchboard or the DTS You can narrow down to the exact area causing the problem by running the POFA in several configurations Changing computers and crypto devices can aid you in determining the malfunction Because of the unique function of the crypto device a single broken line in the switchboard could cause all the bits to be randomly picked up or randomly dropped When the broken wire is on the encrypted side of the switchboard the crypto device reads the state of that line during the decryption cycle and the entire decryption cycle is changed MULTI STATION POFA The multi station POFA is a test of the Link 11 system that involves more than one platform Because this POFA most closely represents normal link operations mo
11. 555355 The hardware chosen for the network plays a part in the choice of network protocol Most users and many of the vendors who build the clone type of equipment would like to see universal interfaces while others think that the availability of different specifications will lead to a proprietary set of equipment even though they favor the overall OSI specifications LAN SYSTEMS When you decide to install a LAN system the type of topology used in the initial wiring of the system will have a major effect on the type of system that can be used There are many LAN systems available each with advantages and disadvantages In the following paragraphs we briefly examine some of the available LAN systems The Institute of Electrical and Electronics Engineers IEEE has developed a set of standards for local area networks These standards encourage the use of common approaches for LAN protocols and interfaces The IEEE LAN standards were developed by a committee of engineers and classified as the 802 standards The 802 standards are broken down even further to define the protocols and topology used in a LAN Some of the standards we are concerned with are the following e IEEE 802 3 Carrier sense multiple access collision detection CSMA CD e IEEE 802 4 Token e IEEE 802 5 Token ring ETHERNET The EtherNet local area network was developed by Xerox the Intel Corporation and the Digital Equipment Corporation
12. 9 2351 1N3Ndino3 JIHdVYOOLdAYD dic d MOLINON l MSS NV diva yous H31N32 95 1N0I 0351 VL YSS NV N3A323M ONIHOLIMS Y3NMWVAYLS 1N3Ndino3 U3LLINSNVML MO ouvwoinv OiHdVil O1dANO 3H 1 65 NV H3AI3O3H SOSSd NIG VIVO UEM VLS WO STSNNVHOSNS st MOSS3OOMd USM Md TVNIWMSL QNV83QOIM JdL 4 25875 TWNINWAL W3OON W3QOW 9 04 2351 17065 6 0S4 NV INN 3Nn URM 1N3Wdino3 uO J3dA13131 VIVO M3HIV3M OlHdvMOO1dANO L MSS NV U3AI303H A S OSM NV 0021 Z TANNWHO 1 3131 NO NOISSIASNVML 0071 JHN SGOW vive SOL Wnulo3ds Qv3Wds JHS 15248 14 31M 3d viva 3oN3OITISINI yO YaSN3O 3 5 ETV30040 NAVMACS and TACINTEL processors for message screening and printing Refer to the discussion of these two systems Weather data is sent directly to printers after decryption Ships not equipped with one or both of these systems will normally output the broadcast to teletypewriters Fleet Broadcast Retransmission At selected shore stations fleet Broadcast message traffic is retransmitted on hf links These stations receive the tdm data directly via cable or satellite CUDIXS NAVMACS The CUDIXS subsystem is a shorebased in stallation of processors and peripheral equipment that provides K link control of the network and processing at shore installations Figure 3 3 shows a
13. Points and Tracks NUMBER OF PARTICIPANTS The number of units that can participate in a Link 16 net has been increased dramatically over that of Link 11 The JTIDS Unit number or JU is a five digit octal number from 00001 to 77777 This allows for a maximum of 32 766 possible JUs Addresses 00001 to 00177 are normally assigned to units that have the need and capability to participate in both Link 16 and Link 11 When a unit participates in both Link 11 and Link 16 it must use the same address on both links For example Link 16 JU 00043 is the same as Link 11 PU 043 TRACK NUMBERS Link l6 replaces the old four digit octal Link 11 track numbers with a five character alphanumeric track number The track number can be within the range 00001 to 77777 octal or 0A000 through 44777 This allows for a maximum of 524 284 track numbers compared with the 4 092 available with Link 11 One reason for the need for the additional track number is that Link 16 cannot operate in the track number pool mode in which a common pool of track numbers is shared by several PUs Every JU must be assigned a unique block of track numbers 7 7 To maintain interoperability with Link 11 Link 16 track numbers 00200 through 07777 designate the same track as Link 11 track numbers 0200 through 7777 TRACK QUALITY The Track Quality TQ value used by Link 16 relates to the accuracy of the reported position of the track The TQ has a range of
14. T A E M 33040934 R tes ee i u3onaoud3u EZ HSN NV sxiano SOVWAVN n sia OVW ALIS 3HOHS WNIWYSL 88 4 05815 savor A eoosn NV 40234 i i 3dvl 13S TWNINYSL NYOL viva 9 79 11 f i r 900 N31SAS NISSIJOYd 9 SCG Viva NOILVOINNWINOO Jo SGdW N31SAS NOILNGIMLSIG QNV ONISSSOOUd 39VSS3N 3 18 SHORE SITE TERMINAL SUBSCRIBER TERMINAL PSK TRANSCEIVER ra MODEM BASEBAND AN WSC 5 V OM 43A USC PATCH SINGLE AN WSC 3 OR OK 367 WSC 3 OK 455 V WSC OR OK 326 WSC 3 TD 1271B U CRYPTO TSEC KW 7 G 84 lt TELETYPEWRITER EXISTING CONTROL INDICATOR C 11330 WSC 5 V D NOT USED IN DAMA MODE TELETYPEWRITER EXISTING CONTROL INDICATOR C 9899 WSC 3 ETV30052 Figure 3 14 DAMA configured teletypewriter subsystem FUNCTIONAL COORDINATION CONTROL REQU UNK NAVAL SPACE COMMAND CENTER EST STATUS AND p DISPLAY_DATA NAVY AIR FORCE CONTRACTOR B TRACKING UXT TELEME AD COMMAND eee REMOTE SATELLITE r OPERATIONAL gt l NAVAL COMPUTER AND Ls ENG TRACKING CONTROL REQUEST TELECOMMUNICATIONS CHANNEL STATUS COMMAND OPERATIONS OPERATION s y STATIONS REPORTING gt CENTER e gt rea a Senen Em OPERATIONAL CHANNEL NOTE FOR GAP FILLER AND LESAT C
15. The signal to noise ratio as measured in dB The SNR is calculated as the average power in the data tones divided by the average power in the noise tones The LMS 11 can measure a SNR of near 34 dB A number preface by the greater than symbol gt indicates that the average power in the noise tones was below the measurable threshold In this case the number represents the data tone signal strength only An SNR value of 30 or higher is considered excellent An SNR value of less than 10 is unusable FRAME CNT A count of all data frames received over the specified number of cycles Data frames include the phase reference frame and control code frames in each message A value that 15 followed by a and color coded yellow is displayed if the frame count of a picket station average is less than or equal to six frames The two start code frames the phase reference frame the crypto frame and the two stop code frames would account for the six frames Therefore if a picket unit transmits six or less frames no actual message data is being received and may indicate a problem with the computer or DTS of the unit A yellow color coded value followed by the is added for an NCS when the number of frames is equal to or less than eight The two additional frames account for the next station address at the end of an NCS report PERCENTAGE THROUGH The THRU column is a number that indicates the percentage of message data tha
16. V 6 TACINTEL shore installations for the same purpose as V 5 V OTCIXS fixed submarine shipboard installations for passing TDP formatted data and teletypewriter traffic V 8 TADIXS ship and submarine installations V 9 TADIXS Gateway Facility TGF e V10 Tactical Data Processor Controller Interconnecting Group ON 143 V USQ Each ON 143 V USQ configuration varies depending on its particular use It fits within limited spaces aboard small ships and submarines performing a variety of functions related to several input output channels of the control processor It provides red black isolation synchronization of units level conversions and crypto test and alarm signals It also provides crypto control and interfaces baseband system components with rf link equipment ON 143 V 4 USQ is shown in figure 3 32 Data Terminal Set AN USQ 69 V The Data Terminal Set shown in figure 3 33 has a 15 inch diagonal screen on which a 2000 character page can be displayed The memory is available in two 3 31 Figure 3 32 Interconnecting Group ON 143 V 4 USQ sizes 2000 and 6000 characters When memory overflows as a result of computer output a computer interrupt is initiated Overflow as a result of operator input causes an audible alarm This unit is currently used with TACINTEL ship and NAVMACS T ess y nan m TR ERAN Maa s Pi Mere FP S ellc f e ee hom
17. Describe the function of the software operating system of a LAN 8 1 LOCAL AREA NETWORK HARDWARE The basic hardware components of a LAN are cables network interface cards network servers peripherals and workstations These components are covered in the material that follows CABLES Several types of cables can be used in LAN applications The selection of the type of cable depends on several factors such as maximum length of a single cable run security requirements and the capacity and speed of the system Twisted Pair Cable The twisted pair cable is easy to install and costs little on a per foot basis In some cases existing telephone cable may be used Its disadvantages include limitations in capacity and speed It is also susceptible to electrical interference unless it 15 shielded Shielded Twisted Pair Cable The shielded twisted pair cable is encased in an RFI shield The stranded wire used as a conductor is manufactured with greater precision and is capable of greater data transmission rates and longer cable runs Coaxial Cable Coaxial cable networks have gained in popularity because of their use in cable television The quantities of cable and connectors produced for cable television have greatly reduced the prices of these components for network users Coaxial cable comes in various thicknesses and is designated by a number RG 11 RG 58 RG 59 RG 62 and so forth You can use either baseband or broadb
18. CONTROL OTCIXS NOTE 2 INDICATOR SATELLITE LINK C 1143 050 le CONTROLLER ON 143 V 6 USQ 4 l l i i ee ee eee a en aa a E E oa EEEE i FORMS AA AIC TVAIQN D 10 Figure U 3 10 TADIXS surface ship installation 3 14 achieved by a polling and controlled access protocol installed in the TADIXS radio controller shore software and the TADIXS satellite link controller afloat software In the non DAMA mode OTCIXS operates in a half duplex manner at a data rate of 2400 bps using a dedicated uhf channel When functioning in the DAMA mode OTCIXS operates at a data rate of 1200 or 2400 bps in a permanently assigned time slot of a uhf DAMA channel Control of message traffic transmission is achieved by a demand assigned access protocol installed in the OTCIXS radio controller shore and satellite link controller afloat software Message Traffic Reception Each subscriber in the TADIXS network has a unique identification number recognized by the subscriber processor This number serves as the initial basis for incoming message traffic screening TADIXS or OTCIXS satellite link controllers on afloat units compare redundant receptions for accuracy and form the most accurate composite of the traffic received For surface ship and submarine users scre
19. Switch 15 in the CORRECT position the DTS is capable of performing which of the following operations 0756 1 Detecting and correcting an even number of bit errors in the received data word 2 Detecting and correcting an odd number of multiple bit errors in the received data word 3 Detecting and correcting a single bit error in each received data word 4 Detecting and correcting a single bit error in the received data message When you depress the TRANSMIT RESET switch on the TADIL A control panel it causes the DTS to perform which of the following operations 1 To immediately stop all transmissions 2 To inhibit the generation of output data requests generating a stop code and ending the current transmission 3 To place the radio in radio silence 4 To inhibit the generation of input data requests generating a stop code and ending the current reception 11 The DTS is configured as a picket station in roll call mode When you depress the TRANSMIT INITIATE switch on the TADIL A control panel it will cause the DTS to perform which of the following operations if any 1 To immediately transmit the data 2 To allow the unit to enter the net 3 To assume control of the net as NCS 4 None On the NCS platform the MISS CALL indicator on the TADIL A panel will light when a picket fails to respond to two successive interrogations 1 True 2 False The address entered into
20. chronization Tdm also results in an increase in the signal bandwidth because of the increased data speed Time division multiplexing also can be used with digital signals but this method is usually called synchronous multiplexing FREQUENCY DIVISION MULTIPLEXING Unlike tdm which samples a portion of the sine wave frequency division multiplexing fdm transmits and receives for the full 360 degrees of the sine wave A channel is subdivided into smaller segments of equal size called subchannels Each subchannel carries a separate signal Fdm used by the Navy can generally be divided into two categories voice and tty communications You can find more information on multiplexing in NEETS volume 17 SINGLE AUDIO SYSTEM SAS The Single Audio System SAS was developed to fulfill the requirement for an integrated secure non secure shipboard voice communications system It consists of telephone sets voice signal switching de vices various control devices and field changes to existing equipment in conjunction with other ele ments of the overall shipboard radio communications system The SAS is essentially the baseband AM and or FM hf vhf or uhf audio subset of the ship board exterior communications system It incorporates voice communications circuits user control over the operating mode both secure and nonsecure and various degrees of operator control over voice circuit selection Figure 2 13 shows the major equipm
21. lights when the DTS 15 in the transmit mode RECEIVE MODE INDICATOR lights when the DTS is in the receive mode SUMMARY FAULT INDICATOR Lights when a fault in the DTS is detected while in the OPERATE mode There are 27 performance monitor fault sensing circuits in the data converter modem of the DTS During the OPERATE mode 14 of these sensors can cause a summary fault The fault sensing circuits monitor areas such as various power supplies signal quality preamble presence timing and audio signal quality When the DTS is in SELF TEST the summary fault lamp is lighted when a fault is 1solated to a function defined by switch positions on the fault isolation control and built in tests routines LAMP TEST BUTTON causes all indicators on the mode control panel the TADIL control panel and the address control unit to light FAULT MONITOR RESET SWITCH In the MONITOR position this switch allows the fault sensing function of the DTS to operate normally and provide a fault summary signal to the DTS control In placed in the RESET position the fault sensing circuits of the DTS are reset The SUMMARY FAULT lamp is turned off when the fault sensing circuits are reset INTERNAL 100 KHZ EXTERNAL SWITCH Allows for the selection of the internal or external 100 KHz frequency standard DOPPLER CORR ON CORR OFF SWITCH Enables the DTS Doppler correction when placed in the CORR ON position FULL DUPLEX HALF DUPL
22. 0 to 15 To achieve the highest track quality the track must be within 50 feet of the reported position Link 11 uses the update rate to determine track quality Using Link 11 a track that is reported by a PU at every interrogation is usually assigned a TQ of 7 Therefore a Link 11 air track with TQ of 7 can be more than 3 nautical miles from its reported position TRACK IDENTIFICATION The Link 16 system greatly expands the information that is reported with Track Identification ID The new ID reports include fields for platform activity specific type and nationality of the track Additional provisions have also been added to identify a track as Neutral and the Unknown Assumed Enemy ID is changed to Suspect FRIENDLY STATUS The Link 16 system also provides for more detailed status reports from friendly aircraft The following fields are added to Link 16 friendly status reports equipment status ordnance inventory radar and missile channels fuel available for transfer gun capability and station ETA and ETD INCREASED GRANULARITY Granularity refers to how precisely an item 15 reported in the link message Link 16 has made major improvements in the granularity of reports concerning track position air track speed altitude and lines of bearing LINES AND AREAS The Link 16 system allows the reporting of multi segment lines and areas of all sizes and descriptions Link 11 for comparison only al
23. 57080 0 aL OM 43A USC Oo Bn iene SINGLE 5 3 ON 143 V 6 USQ OK 326 WSC 3 I i HANDSETS CLEAR ANALOG NPAT 00 ie OR VOICE TSEC XG 36f OK 367 WSC 3 i CLEAR DIGITAL 2400 BPS VOICE Ceri impr 88 AJITOVON ____ VCVUURE OUDOT 21 ee FAW ti WOE Y JVI p ENCRYPTED DIGITAL DSCS 2400 BPS VOICE SHF a _ gt CONTROLLER LINE u Ira MODEM TsEc xe 13 ee TRU CLEAR ANALOG SECURE INTER DIGITAL pa VOICE gt VOICE CONNECTING GROUP BOARD CONVERTER pae e BLACK ON 143 V 4 USQ Hi auno MU H TONS PATCH PANEL eed ey 20 CHEGARD i cc TSEC KG 34 H2 7 i tsecrKe 3s E E 1 IT TSEC KG 36 tA nee i M lt 333370 L ra vace SUBSYSTEM OPERATOR CONSOLE ETV30045 Figure 3 7 Secure Voice subsystem The second method requires a different process and is used if the channels are busy or if procedures require this method For the small ship or submarine a voice t
24. Figure 3 24 Typical receive only system low level teletype equipment A receive system is shown in figure 3 24 The receiver system includes up to four AS 2815 SSR 1 antennas with an Amplifier Convertor AM 6534 SSR 1 fib 3 25 It also includes a Combiner Demodulator MD 900 SSR 1 fig 3 26 and a Demultiplexer TD 1063 SSR 1 fig 3 27 The antenna and convertors are mounted above deck in positions that ensure that at least one antenna 15 always in view of the satellite The combiner demodulator and demultiplexer are mounted below deck The receiver accepts rf signals between 240 MHz and 340 MHz a modulation bandwidth of 25 kHz The combiner demodulator demodulates the rf input from the amplifier convertor and provides a 1200 bps output for the demultiplexer The demultiplexer accepts an input of 1200 bps and outputs 15 channels at 75 bps The decrypted demultiplexer output is patched to NAVMACS TACINTEL processors or tele typewriters 3 28 Antennas SATCOM antennas will be discussed in volume 7 of this training series SSR 1 AS 2815 SSR 1 AMPLIFIER CONVERTER RECEIVING ANTENNA ETV30063 Figure 3 25 Receiving Antenna AS 2815 SSR 1 and Amplifier Converters AM 6534 SSR 1 ETV30064 DEMULTIPLEXER 2 92 NL A wa ore ETV30065 Figure 3 27 Demuldtiplexer TD 1063 SSR 1 Modem Group OM 43A USC The OM 43A USC shown in figure 3 28 15 used primarily with the AN WSC 5 V transceive
25. The transceiver output is fed to the receiver transfer switchboard The switchboard output is connected to either radio set control or to a speaker amplifier AM 3729 or both depending on the user s preference The output of the radio set control is fed to the handset and the speaker amplifier output is routed to the speaker ULTRAHIGH FREQUENCY COMMUNICATIONS The ultrahigh frequency uhf band is used for line of sight short range command and control communications As we stated earlier line of sight means that both antennas are aimed at one another with no obstruction in between This band is also used for satellite com munications Satellite communications are line of sight communications because the antennas remain p eee NONSECURE RADIO wt i HANDSET CONTROL Lo Lo C 1138 LO j ER TRANSFER SWITCHBOARD SB 988 SRT Le 9 0 SP E AL 5 ECURE SECU RE REMOTE VOICE VOICE UNIT MATRIX EQUIPMENT in sight of each other though the distance traveled by the signal is much greater than for surface communications The uhf system uses a transceiver However we will still describe the transmit and receive functions separately Although this description pertains to voice communications uhf equipment can process tty data in the same way that the hf system does Uhf Transmit A basic block diagram of a uhf transmit system is shown in figu
26. WN I Decrypts the 24 bit data word and sends it to the CDS computer 1 A Zo B Se ue Au cB Which of the following functions is performed by an antenna coupler 1 Amplification of the radio signal 2 Impedance matching of the antenna and the radio set 3 Conversion of atmospheric electromagnetic energy to RF current 4 Coupling of the data terminal set to the radio The size of an antenna is determined by which of the following factors The operating power UP 2 The operating frequency 3 The range of the receiver 4 The type of data being transmitted Ihe frequency range of an antenna can be extended by adding which of the following factors 1 A resistive load only 2 A capacitive load only 3 An inductive load only 4 Either a capacitive or an inductive load Which of the following functions is NOT performed by the data terminal set 1 Generating the radio key line signal 2 Converting digital data To audio tones 3 Encrypting CDS computer data 4 Converting audio tones to digital data 12 Su obs Ihe data terminal set communicates with the radio set via which 0f the following devices 1 The communications switchboard 2 An antenna coupler 3 The cryptographic device 4 The SGS computer Which of the following radio frequency modulation methods is used to minimize propagation caused signal loss during HF Link 11 operations 1 Q
27. flexibility and limitations 3 2 Capacity Currently military SATCOM systems can provide communications between backpack shore airborne and shipboard terminals These SATCOM systems can handle thousands of communications channels at the Same time Reliability SATCOM frequencies are only slightly affected by atmospheric phenomena and do not depend on reflection or refraction Reliability 1s based on the skill of operators and maintenance personnel and the condition of the satellite communications equipment Vulnerability Communications satellites are relatively safe from threats of harm Because these satellites are in such high orbits any attempt to disable or destroy them from the Earth would be difficult and expensive However Earth terminals are a different story They offer a more attractive target for destruction by conventional methods But these terminals can be protected by the same methods taken to protect other vital installations So overall the satellite system is nearly free from harm by an enemy Operationally highly directional earth terminal antennas provide a high degree of freedom from jamming The wideband system can use antijamming techniques which also reduces vulnerability Flexibility Mobile military satellite earth terminals with trained crews can be deployed and put into operation anywhere in the world within hours Limitations The technical characteristics of the satellite and its
28. subassembly is not always clear An assembly maybe considered a subassembly when it is part of a larger or more complex assembly A computer keyboard is a good example By itself it is an assembly However it is also a subassembly in a total computer system Another example you are very familiar with is a circuit card 35 FOOT wwe ANTENNA r ANTENNA er COUPLER pu CONTROL 5 7 5 AC RADIO TRANSMITTING SET ETV30013 Figure 2 1 Communications system pictorial view 2 2 A PART is one component a combination of two or more components A part cannot normally be disassembled without being destroyed Resistors capacitors and transistors are examples of parts EQUIPMENT CONFIGURATIONS The wide variety of communications equipment aboard ship can be overwhelming This section separates that equipment into types of systems and identifies typical equipment associated with each type of system EXTREMELY LOW FREQUENCY VERY LOW FREQUENCY COMMUNICATIONS The extremely low frequency elf com munications system is used to send short phonetic letter spelled out PLSO messages from the Continental United States CONUS to submarines operating at normal mission speeds and depths Elf can penetrate ocean depths to several hundred feet with little signal loss This allows submarines to operate below the surface improving their survivability by making detection more difficult
29. unusable BER This is the bit error rate per thousand The incidence of bit errors increases as the signal to noise ratio decreases MISSED CODES PERCENTAGE This is a percentage of each type of code that 15 missed The number of codes start stop and address call ups missed and received is tabulated and the percentage of each type missed is calculated FRAMES This is the total number of data frames received including the phase reference and control code frames CS This field displays the carrier suppression value of the upper and lower sidebands as a ratio of the power in the 605 Hz to the power of the carrier frequency The value display is measured in dB RFE DS The radio frequency error or Doppler shift of the received signal in Hertz The display is color coded cyan if frequency correction was disabled during LMS 11 initialization Spectrum Display The spectrum display graphically shows the power levels of all the Link 11 tones and the noise tones that are the odd harmonics of 55 Hertz The spectrum display screen is shown in figure 5 13 The x axis of the bar graph is numbered from 1 to 30 to represent 30 tones Tone 05 is the 605 Hz Doppler tone Tones 8 through 21 and tone 26 are the data tones The remaining tones are not used by the Link 11 system but are sampled and displayed to give the operator an indication of the noise level The y axis of the bar graph displays the relative power of eac
30. 4 Four Subsystems consist of two parts What are they 1 Baseband equipment rf terminal 2 Multiplexing equipment satellite 2v Satellite rr Lerminal 4 Transmitters receivers 2a 2 525 zu 2520 In modes 1 through 6 what are the uplink and downlink frequency bands used in Fleet Satellite Broadcast HE SEE Uhf hf Ung SAI olt unf Hm CO BO pL What system do subscribers use to receive Fleet Satellite Broadcast AN BRA 1 AN FRT 1 AN SSR 1 AN VRC 1 H Co PO Fe What is the minimum number of broadcast channels that NAVMACS guards automatically 1 One 2 3 Three Four What is the bandwidth in kHz of the satellite channels allocated to CUDIXS NAVMACS Dao Ze cie Su 4 25 What term is associated with a submarine commander s ability to receive messages via Satellite at scheduled intervals Group broadcasts Interval broadcasts Network broadcasts Timed broadcasts CO Lm Secure voice uses digitized voice with a 3 kHz voice channel What type of voice modulation does this describe Zi 1 Multiband 2 Narrowband 3 Singleband 4 Wideband LEUR 22 9 2 904 2554 When using Secure Voice a ship must contact what authority before initiating communications with a shore command Fleet controller Group controller Net controller Voice controller PS GA cN pa Which of the following is a subsystem specifically d
31. 4800 bps depending upon the ocean area The DAMA multiplexed data stream is divided into frames with each frame being 1 386 seconds long Each frame is subdivided into time slots as shown in figure Most of the DAMA frame formats are derived from this basic format In the following paragraphs we will name and describe the purpose of each slot Channel Control Order Wire CCOW Slot This slot is used to transmit system timing and control information from the channel controller to subscriber units only It provides subscriber units with system timing configuration and satellite rf control information It occurs at the beginning of each frame Return Channel Control Order Wire RCCOW Slot This time slot provides limited order wire capability for DAMA related subscriber to channel controller communications It 15 used for transmission from the subscriber to the channel controller Ranging Time Slot This is the time slot during which the user s TD 1271B U determines the range between the user terminal and the satellite to set the transmitter syn chronization required for timing All DAMA multi plexer transmit times are referenced to the satellite Link Test Slot The link test slot is used to evaluate the performance of the satellite link Each subscriber is able to transmit a fixed data stream through the satellite receive that bit stream and then perform error analysis automatically MK FR
32. 605 Hz Doppler tone or the 2 915 Hz tone when used as the Sync tone SUBSCRIPTS o AND e MEAN ODD AND EVEN oe CHANNELS CHANNELS GOING FROM 1 TO 32 REFERENCE PHASE OF TONE IN LAST FRAME ROTATION FROM PREVIOUS FRAME S VECTOR 38NP0157 Figure 4 14 Link 11 data phase shift encoding 4 12 Each of these angles marks the center of a quadrant as shown in figure 4 14 Each 90 degree quadrant is assigned a two bit binary value Any phase difference falling within that quadrant represents that binary value This system of data encoding can tolerate an error in the prescribed phase shift of up to 44 degrees before a single bit error will Occur An error in phase shift that is greater than 45 degrees but less than 135 degrees will cause the phase angle to fall into an adjacent quadrant Notice that the values are assigned to each quadrant in such a way that if a phase shift error occurs that only one bit error will be introduced as long as the quadrant into which it falls is adjacent to the target quadrant Link Protocol and Interface Control In addition to encoding data from the CDS computer the DTS generates and recognizes protocol data that controls the type and number of link transmissions These protocol words include codes indicating the start of transmission the end of transmission and the address of the next unit to transmit The interface with the CDS computer is under the control of the DTS The DT
33. 605 Hz Lone and the 2195 HZ tones are displayed Which of the following setup entries S30 would cause this display 1 The RESTRICT field set to preamble only 2 The RESTRICT field set to data only 3 The PU field is set to a unit not in the net 4 The SIDEBAND SELECT is set EO USB Only The CDS computer outputs serial Sr digital data to the Link 14A Dos 1 True 2 False 21 and New Technology in Data Communications 5 Link ll Fault Isolation chapter 5 pages 5 17 through Link 4A chapter 6 pages 6 1 through Ww chapter 7 Link 4A is used to transmit which of the following types of information 1 High speed computer to computer tactical infrormabron 2 Tactical information CDS simo wo Ship 3 Aircraft control and target information 4 All of the above Link 4A data is transmitted by using which of the following methods Frequency shift keying Phase shift keying Audio frequency tone shift Quadrature differential phase shift keying CO BDO Ln What is the maximum number of aircraft that can be controlled by a single Link 4A controlling station Ls GA Aa OO Dec d 4 100 Aircraft control messages from the Link 4A controlling station are developed by the CDS computer using which of the following types of information 1 Radar derived target data 2 Reply data from aircraft 3 Other sources of tactical IN orma ON 4 All of the above L
34. After completing this chapter you should be able to e Describe the functions of the Link 4A_ system Describe the operating modes of the Link 4A data terminal set Describe the types of messages used by the Link 4A system e Describe the functional operation of the Link 4A data terminal Describe the test messages used in the Link 4A system LINK 4A SYSTEM OVERVIEW The two major components of the Link 4A system are the Link 4A CDS system and the CAINS system Both systems use serial time division multiplexing to transmit control and reply messages over a frequency shift keyed FSK UHF radio communications channel The CAINS system can also transmit data via hard wired stations on the flight deck or hangar deck LINK 4A CDS SYSTEM The Link 4A CDS system is used to provide one way or two way communications between the controlling station and up to 100 controlled aircraft The controlling station transmits to the aircraft control messages containing vectoring information commands and data pertaining to the target or destination of the aircraft The aircraft transmits reply messages containing information concerning its heading altitude airspeed and tactical readiness The aircraft control messages are developed by the CDS 6 1 computer using radar derived target data reply data from the aircraft and other tactical data A typical shipboard Link 4A system configuration is shown in figure 6 1 It consists of
35. EV 0054 Figure 3 16 Uhf satellite coverage areas SATELLITES In 1976 three satellites were placed into orbit over the Atlantic Pacific and Indian Oceans These satellites called MARISATs were procured by and are managed by the COMSAT General Corporation Each satellite has three uhf channels for military use one wideband 500 kHz channel and two narrowband 25 kHz channels The uhf section of each satellite is leased to the Navy for communications To distinguish the special management and control functions for communications on these uhf channels the Navy has given the leased MARISAT satellite assets the name GAPFILLER Current planning calls for no Navy use of GAPFILLER satellites after the mid 1990 s Satellite coverage will then be provided by a combination of FLTSAT and LEASAT until the new UHF FOLLOW ON UFO satellites are placed into service The Navy plans to have two operational satellites in each of four satellite coverage areas Each satellite coverage area can be terminated in at least two NCTAMS allowing around the world connectivity You can see this connectivity in figure 3 16 FLTSATCOM SATELLITE The FLTSATCOM satellite consists of two major parts a payload module that includes the antennas and a space craft module with a solar array The payload module contains the uhf shf and S band tracking telemetry and command communications equipment antennas The communications equipment is mounted intern
36. G H J K L y ENTER NN ___ PL NE NON ee AE ms Cy CD CE Wy WE WE __ __ _ __ y ___ gt BACK SHIFT Z X V B M lt SHIFT jz 38NP0197 Figure 5 4 The LMS 11 keyboard The analog to digital converter converts the Link 11 audio signal into a digital signal for use by the LMS 11 This digital signal is then transferred to the computer where the FFT converts it to a frequency domain The Fast Fourier Transform consists of a complex mathematical formula used to determine the phase shift of a signal AUDIO INTERFACE UNIT The audio interface unit connects the upper sideband USB and lower sideband LSB audio signals from an HF radio the USB from a UHF radio to the LMS 11 The audio signals are input to the analog to digital converter of the control processing unit The audio interface unit does not add a load to the audio signal DUAL 3 5 INCH FLOPPY DISK DRIVE UNIT The dual 3 5 inch floppy drive unit is used to load the LMS 11 programs and to record Link 11 data The disk drives use 788 Kbyte double sided double density disks 5 8 POWER CONTROL UNIT The power control unit provides the control distribution and conditioning of the 115 VAC input power Control Display Group CDG The CDG consists of a color graphics monitor and a keyboard The monitor displays operator entered data and system operati
37. I 0d I L AN USC 20B 4 SMART a owe dorem _ emere AN UGC 136AX CONNECTING I UNIA I VOU ii GROUP i EAM RECORDER ON 143 V 5 USQ 1 1 TRAFFIC RECORDER KEFKULDUULIX din i REPEODUCER KEYBOARD PUNCH ov V 6 EXISTING af Ji o 1 CONNECTING J me TSEC KG 36 i i GROUP CV 3333 U MODEM ee TT 835 U SSIXS I wm Pod SUBSCRIBER Pee A aes TERMINAL i i SUBMARI NE l lt i OR OPERATOR M CONSOLE AN USQ 64 V 3 i ISABPS TO SPARE AN 32 FSQ NOT SHOWN i RECORDER AN FSQ 163 GENSER REPRODUCER 1 NOT PART OF ssixs i RP 357 FSQ AN FSQ 164 SI ae ee ee ee HOO ETV30044 Figure 3 6 SSIXS subsystem SSIXS has undergone an upgrade SSIXS II that replaces the SSIXS shore equipment with new computer equipment Message Traffic Input At the broadcast control authority BCA the console keyboard operator high speed paper tape reader or Submarine Message Automated Routing Terminal SMART enters into the SSIXS shore terminal messages addressed to submarines that have been received AUTODIN NAVCOMPARS or locally over the counter in the message center Aboard the
38. It became the model for the development of the IEEE 802 3 standard The original standard defined a maximum throughput for EtherNet of 10 Mbit s but it has been revised to support throughput of much higher rates When operating over coaxial cable EtherNet has a 20 Mb per second throughput speed For high demand environments such as engineering or graphics EtherNet is often the choice It is a bus topology and uses CSMA CD protocol It is available in the following three versions standard EtherNet ThinNet and twisted pair EtherNet Standard EtherNet and ThinNet both use coaxial cable Standard EtherNet is somewhat more expensive and more difficult to install than ThinNet but it allows networking over greater distances with more users Twisted pair EtherNet uses a distributed star topology with wiring concentrator hubs not the bus topology characterizing standard EtherNet and ThinNet Connecting more than 100 users on a standard EtherNet trunk or on a series of twisted pair concentrators 1s not uncommon while ThinNet LANs usually support less than 50 users All versions of EtherNet create a LAN with high interconnectivity options A number of products are available for connecting EtherNet LANs to minicomputers and mainframe computers and for bridging to other LANs examples are STARLAN ARCnet and IBM Token Ring Network STARLAN STARLAN uses a star topology with a CSMA CD protocol Its throughput speed is 1 per second o
39. Logicon Inc San Diego CA 1990 Preliminary Technical Manual System Maintenance Organization Level AN UYQ 62 V 1 2 Command and Control Processor C P Subsystem SPAWAR EE600 AB SLM 010 Space and Naval Warfare Systems Command Washington DC 1992 Radio Set AN PRC 104 A Technical Manual TM 11 5820 919 12 U S Army Communications Electronics Command Fort Monmouth NJ 1986 Shipboard Electronics Material Officer NAVEDTRA 12969 Naval Education and Training Program Management Support Activity Pensacola FL 1992 System Operation and Maintenance Manual AN USQ 74 74 Data Terminal Set SPAWAR EE600 AA OMI 010 Space and Naval Warfare Systems Command Washington DC 1990 Technical Manual Installation Operation and Maintenance with Illustrated Parts Breakdown Computer Adapter MX 9222 U NAVSEA 0967 LP 563 9060 Naval Sea Systems Command Washington DC 1977 Technical Manual Operation Maintenance with Illustrated Parts Breakdown Address Control Indicator C 9062 U NAVSEA 0967 LP 563 9040 Naval Sea Systems Command Washington DC 1977 2 Technical Manual Operation and Maintenance with Illustrated Parts Breakdown Data Terminal Set Control C 9063 USQ 59 NAVSEA 0967 LP 563 9050 Naval Sea Systems Command Washington DC 1977 Technical Manual Operation Maintenance Manual with Illustrated Parts Breakdown Digital To Analog Converter CV 2969A P U NAVSEA 0967 LP 563 9070 Naval Sea Systems Comm
40. NAVMACS transmissions Each channel 15 operated as a half duplex uhf link with a data transmission rate of 2400 bps The rf modulation is differential encoded phase shift keying DPSK SHIPBOARD SITE CONVENTIONAL on SYSTEM TELETYPEWRITER SET SUBMARINE SATELLITE INFORMATION EXCHANGE SUBSYSTEM NON DAMA SSIXS was designed to compliment and mf hf communication links between shorebased submarine broadcast control authorities BCAs and submarines shows a SSIXS subsystem This commander the ability to receive messages transmitted via satellite at scheduled intervals Group Broadcasts Between Group Broadcasts submarines may transmit messages to the BCA including a request for messages held in queue The shore terminal responds with acknowledgements for the received messages and transmits all messages addressed to that particular submarine Two modes Group Broadcast and Query Response permit the submarine to be active or passive depending on what the submarine commander wants One 25 kHz wideband channel on each of the four FLTSATCOM satellites has been allotted to SSIXS A single SSIXS network may have up to 120 submarine subscribers subsystem provides the submarine SHORE SITE 7 gt oe UNE RECORDER REPRODUCER MODEM IC MOI PERFORATED TAPE RD 397B V 3 U
41. NICP it does so by using the shared global memory in the DDP A port to port transfer is a transfer of data between ports such as when communicating with the host external timer see fig 7 9 SECURE DATA UNIT The SDU is a removable assembly that is mounted to the IU It stores the cryptovariables that are loaded during initialization The SDU provides for both message security and transmission security Message security is provided by the encryption of the data while transmission security is provided by the pseudo random frequency hopping pattern and the introduction of a pseudo random pattern of noise and jitter on the RF signal RECEIVER TRANSMITTER GROUP The R T 18 in the top drawer of the equipment cabinet and processes the radio frequency signals The R T also generates 75 MHz intermediate frequency signal used for internal communication between the R T and DDPG When a Link 16 message is received the R T converts the RF to the intermediate frequency and sends it to the DDPG for processing When the terminal transmits a Link 16 message the R T receives a Continuous Phase Shift Modulation CPS IF signal from the DDPG The R T then converts it to a 200 watt RF signal that 15 sent to the high power amplifier group HIGH POWER AMPLIFIER GROUP The HPAG is in the second drawer of the equipment cabinet and consists of a high power amplifier and the antenna interface unit AIU The signal from the R T group is r
42. Textbook Assignment Link 11 System chapter 4 pages 4 18 through 4 19 continued Lunk ll Fault Isolation chapter 5 pages 5 1 CREOS i 4 1 total of how many data tones 4 5 When operating the Link 11 with are in the composite tone UHE radio set you should package developed by the DTS place the SIDEBAND SELECT switch in what position only lI 21 2 14 ke 3 2159 24 4 16 Ju DIV 4 AUTO 4 2 The intelligence data bits in a data tone is stored by which dco Wath transmitting on of the following methods the HF range and the sideband select switch set to the AUTO 1 Phase shifting the tone by a position which of the predetermined amount with following priorities are used respect to the following by the DTS to find the data frame word with no errors to send to 2 Phase shifting the tone by a the COnpULer predetermined amount with respect to zero degrees 1 LSB USB DIV 3 Phase shifting the tone by a 2 LSB DIV USB predetermined amount with dc DIN eb Use respect to the preceding 4 DIV USB LSB frame 4 Increasing or decreasing the 22 he tado cs zn che amplitude of the data tone transmit mode when the key line with respect to the Too 3 eI preceding frame 1 True 4 3 During receive operations 2 False exactly how many EDAC bits are extracted from the received 1 0 Which of the following data tones conditions would NOT be a valid reason for changing the
43. The frequency at which a radio operates determines what size antenna is most suitable for transmitting and receiving The higher the frequency the smaller the antenna will be Lower frequencies require larger antennas For example the full wave length of an antenna designed to operate at 4 MHz is about 250 feet long Since this length is too large for shipboard application antennas designed in submultiple lengths These include half wave and quarter wave antennas An antenna can be tuned by introducing a capacitive or inductive load This loading effectively changes the electrical length of the antenna and can be used to extend the frequency range of the antenna For more information on antenna design and operation refer to the Navy Electricity and Electronics Training Series Module 10 Introduction Transmission Lines and B72 10 00 93 To Wave Propagation Antennas NAVEDTRA Transmission Cycle The data flow for the Link 11 transmission cycle is shown in figure 4 4 CDS computer receives data from the various ship s sensors navigation systems and operator entries and stores this data in a data base When a Link 11 transmission is required the computer outputs parallel digital data through the SGS computer to the cryptographic device The cryptographic device encrypts the data and sends the encrypted data to the data terminal set DTS The DTS converts the digital data to analog audio tones keys the transmitter u
44. The massive amount of information ETs can be questioned on and expected to know can be frustrating But the goal YOU and every ET must have is to become as knowledgeable as possible to be better prepared for all future challenges After completing this chapter you should be able to e Identify the basic principles of rf communications e Recognize the basic equipment used for rf communications e Determine the frequency spectrum allocated to rf communications RADIO COMMUNICATIONS Navy ships planes and shore bases operate as a team working together to accomplish a specific task Radio equipment is used to coordinate the activities of the many fleet units by linking them with each other and with shore stations Radio can be defined as the transmission and re ception of electronic impulses or signals through space by means of electromagnetic waves Usually the term is used in referring to the transmission of intelligence code and sound signals although television and radar also depend on electromagnetic waves At one time the term radio communications brought to mind telegraphy CW voice AM and possibly teletype communications Today s radio com munications has become a highly sophisticated field of electronics You the technician need to become fa miliar with the diverse systems in use today The primary means of communicating between ships and between ships and stations is known as tele communications Telecommunica
45. The normal configuration of the 2s dB multi frequency link options Du We uses a T OD 2 3 HF frequencies and b De30 Thats Ves is Used to verity the y 2 operation of the computer UHF frequencies interface crypto device and the data terminal interface 2 CD 1 8 25 a 3 b 1 94 a 2 OJ 2 ba 46 4 3 b 2 Zi B S E 4 F 5 39 This test places the DTS in full duplex mode to run a single station POFA with the Radio echo test Loopback test 1 Loopback test 2 radio Loopback test Loopback test 4 1 DTS fault isolation test 2 p oC 4 D FIGURE 4A 5 40 This option performs an internal self test of the DTS aucdoo courte O OU 30 9 423 9 44 DSi The data terminal can be 5 46 controlled from a remote location by use of which of the following pieces of equipment 1 A 286 personal computer only 2 386 or better personal computer only oe The 1241297050 125 Contre Unire only 4 Either a 386 or better personal computer or the Quy C 12428 USQ 125 Control Unit Link 16 uses which of the following communications propodols 1 Netted or roll call 2 Time division command and response DE S 3 Time division multiple access 4 Frequency division multiplexing Each Unit participating am a Link 16 net is identified by assigning each unit what type of designator 5549 1 A PU number 2 A JU number 3 A link identif
46. Transport Session H CG N Fe 29 0 0 es 6 40 6 41 642 Based network conditions and priority of service what layer of the OSI reference model decides which physical pathway the data should take Physical Data link Network Transport H CO DRO Fe The application level layer of the OSI reference model provides the protocols for which of the following user items 1 Media interface 2 Electronic mail 3 Routing of messages between networks 4 Data compression Which of the following is NOT a LAN topology 1 Linear 2a RING Se OL 4 EtherNet Which of the following features of a linear bus topology should be considered an advantage 1 Signal interference when nodes are too close to each other 2 System remains operable even when one or more nodes fail 3 Very secure system 4 Very easy to run system diagnostics from the LAN administrator In which of the following network topologies if any is each node individually connected to the network server 1 Linear bus Ze Star 9 RING 4 None of the above 6743 6 44 6 45 6 46 Which of the following network access methods requires each node to wait for permission to transmit data 1 CSMA 2 CSMA CD 3 Token passing 4 Contention On a network that uses the CSMA CD access method which of the following actions if any will be taken when a data collision is detected 1 The workstation wil
47. and AN FRC 170 V are used to relay multiplex signals from point to point A simplex relay system pro vides one way communications and consists of a transmitting terminal a certain number of repeaters NONSECURE RADIO SET HANDSET CONTROL C 1138 SPEAKER E T AMPLIFIER SPEAKER AM 3729 SECURE SECURE VOICE REMOTE MATRIX PHONE UNIT SECURE Figure 2 9 Uhf receive TERMINAL STATION NO 1 TERMINAL STATION LIA A INA 2 A SIMPLEX RELAY SYSTEM TERMINAL STATION NO 1 poe REPEATER STATION I R T R T i l Lam B DUPLEX RELAY SYSTEM NOTE R IS ABBREVIATION FOR RECEIVER ETV30022 T IS ABBREVIATION FOR TRANSMITTER Figure 2 10 Basic microwave relay system and a receiving terminal Figure 2 10 shows you such a system A duplex relay system figure 2 10 provides two way communications by using two simplex systems one transmitting in one direction and the other transmitting in the opposite direction The duplex system is further refined by using a single antenna for transmitting and receiving This 1s done by using different transmitting and receiving frequencies and by using a duplexer in the transmission line The rf equipment in terminal and repeater stations are basically the same Terminal equipment can be converted to repeat
48. another KY 879 P where the message can be read on the device s display screen The device can send messages at 300 or 1200 baud in the satellite mode and 266 6 baud when connected to the AN PRC 70 74 INTRODUCTION TO COMMUNICATIONS LINK INTERFACE PLANNING SYSTEM CLIPS The Communications Link Interface Planning System CLIPS was introduced to the Joint Special Operations Community in 1986 CLIPS is a system designed to help the communications planner SATELLITE RELAY STATION WU 8 8 225 400 MHZ Y GAIN MEDIUM Vs ANTENNA RXMT CADIE LL BACKPACK AN RADIO SETI EN PRC 70 100 FEET 27 30 76 MHZ 77 ETV30A38 Figure 2 27 Basic retransmission scheme GROUNDING LCD DISPLAY COMMAND KEYS CURSOR LED S PRESSURE SCREW SCROLL 5 LEFT PACE BAR DELETE KEY KEYBOARD SCROLL NEW LINE KEY RIGHT ETV30B38 Figure 2 28 KY 879 P keyboard determine interoperability in joint operations involving single channel tactical radio equipment Equipment planning in the Special Operations Community is complicated by the wide variety of equipment used and the highly variable and rapidly changing nature of the operational settings Because most communications requirements for this community are satisfied by single channel full duplex radio links CLIPS was designed primarily to help plan this type of communications link Equipment covered under CLIPS is specifica
49. at the tuned frequency indicates the selectivity of the re ceiver Fidelity Fidelity is a receiver s ability to reproduce the in put signal accurately Generally the broader the bandpass the greater the fidelity Measurement is taken by modulating an input frequency with a series of audio frequencies and then plotting the output measurements at each step against the audio input The curve will show the limits of reproduction Good selectivity requires a narrow bandpass Good fidelity requires a wider bandpass to amplify the outer most frequencies of the sidebands Knowing this you can see that most receivers are a compromise between good selectivity and high fidelity AM SUPERHETERODYNE RECEIVER The superheterodyne receiver was developed to overcome the disadvantages of earlier receivers A block diagram of a representative superheterodyne re ceiver is shown in figure 1 7 Superheterodyne receiv ers may have more than one frequency converting stage and as many amplifiers as needed to attain the de sired power output FM SUPERHETERODYNE RECEIVER Fundamentally FM and AM receivers function similarly However there are important differences in component construction and circuit design because of differences in the modulating techniques Comparison of block diagrams and 1 8 shows that electrically there are two sections of the FM receiver that differ from the AM receiver the discriminator de tector and the accompan
50. becomes available as DAMA is installed on each platform To provide maximum flexibility during the transition capability is provided at the shorebased master control stations to interface non DAMA and DAMA users Figure 3 14 shows a DAMA configured teletypewriter subsystem CONTROL SUBSYSTEM The Control Subsystem is structured to perform the following tasks Sense and collect system status information in a defined geographical area and on a worldwide scale Control system resources and the degradation of system capability The Control Subsystem is a combination of several areas and levels of command The major players are listed below The Chief of Naval Operations is the executive authority for all SATCOM system The Commander Naval Space Command is responsible for the operational control and management of these systems and for the effective operation and maintenance of assigned Navy resources for the Department of Defense The Naval Computer and Telecommunications Command performs the required functions to vide day to day control and operation of naval satellite communications assets With coordination system resources can be adjusted to meet operational needs O Oo A gt remore CONVERTER og connect SWITCH ge Lg 1 3 V MET Po TT T XG 36 HANDSETS CLEAR ANALOG CLEAR DIGITAL VOICE 2400 BPS VOICE I 1 TD 12
51. changed in the Link 16 system to what identifier 1 Neutral 2 Suspect 3 Unknown assumed hostile 4 Hostile Link 16 has added which of the following data fields to friendly aircraft status reports 1 Ordnance inventory 2 Equipment Status 3 Fuel available for transfer 4 All of the above The Relative Navigation function of the Link 16 system is required for which of the following functions Maintain synchronization Maintain position Devect COUrSe errors Correct the navigation plot Hm CO BO LE 6 11 Which of the following equipment configurations fully implements the capabilities of the Link 16 system 1 Model 3 2 Model 4 3 Model 5 4 Model 6 6 12 Using the Link 16 Model 5 system link data generated by the ACDS computer is normalized to be independent of any particular system 1 True 2 False 0 15 Using the Link l16 Model 5 system which of the following components formats link data for transmission over any one of the three data links ACDS C2P Link 16 data terminal LDS OONouLer A Digital data processor group B Receiver transmitter group C High power amplifier group B E Power interface unit Secure data unit Figure 6 HL CGO IN ANSWERING QUESTIONS 6 14 THROUGH 6 17 SELECT FROM FIGURE 6A THE EQUIPMENT COMPONENT GROUP OF JTIDS TERMINAL THAT PERFORMS THE FUNCTION OR OPERAIION DESCRIBED IN THE QU
52. controls the receiver transmitter and the high power amplifier groups The DDP performs the processing required for transmitting and receiving Link 16 messages This processing includes the following Data encryption and decryption Error detection and correction encoding and decoding Generation of the frequency hopping pattern Selection of the carrier frequency Measurement of time of arrival data for position and synchronization calculations JTIDS C2P CDS Class 2 Terminal JTIDS Class Terminal Figure 7 9 The Digital Data Processing Group functional block diagram Execution of the Built in Tests BIT for fault isolation Generation of alerts The Network Interface Computer Program NICP is the software that runs in the DDP and 15 responsible for the communications with the JTIDS RF network The NICP controls transmission and reception processing coarse and fine terminal synchronization relative navigation message processing and terminal and network monitoring Figure 7 9 Jis the block diagram for the DDPG The global memory in the DDP is shared by all the processors in the terminal Communications between the processors is over an internal bus called the plain text bus All transactions on the plain text bus are either read or write commands to the global memory port to port transfers When the SICP running in the IU needs to communicate with the
53. does not intentionally carry classified information but because of the coupling mechanism with the RED equipment might carry compromising information is designated SECONDARY RED Some examples you are probably familiar with are indicator lines and control and timing lines Power distribution panels and grounding systems serving RED conductors are also designated SECONDARY RED BLACK CRITERIA The BLACK designation applies to all conductors and equipment involved in handling or processing unclassified plain language and encrypted information in electrical form It also applies to all facilities and circuits that are not designated RED PORTABLE AND PACK RADIO EQUIPMENT Because portable and pack radio sets must be lightweight compact and self contained they are usually battery or generator powered have low output power and are either transceivers or transmitter receivers Navy ships and Special Forces carry a variety of these radio sets for amphibious and emergency communications with the equipment type varying according to the needs of the ship or command The following paragraphs introduce some of these equipment AN CRT 3A Radio transmitter AN CRT 3A popularly known as the Gibson girl is a rugged emergency transmitter carried aboard ships and aircraft for use in lifeboats and liferafts Shown in figure 2 21 it operates on the international distress frequency 500 kHz and the survival craft communication fr
54. effectively a return of the MCM data content which indicates that the internal and interface tests were successful THE LINK 4A SYSTEM COMPONENTS The Link 4A system consists of the CDS computer a data terminal set a communications switchboard and a radio set CY 4881 SSW 1C CABINET 1A1 DIGITAL TO DIGITAL CONVERTER CV 1458B SSW 1A 1A2 MONITOR TEST PANEL SB 1860B SSW 1A 1A3 COORDINATE DATA TRANSFER CONTROL C4476C SSW 1A PANEL SB 1860B SSW 1A 1A5 DIGITAL TO DIGITAL CONVERTER CV 1458B SSW 1A NAME PLATES UNIT NOMENCLATURE AND LOCATION AFTER MODIFICATION 1A4 MONITOR TEST TO AN SSW 1D AM 6528 SSW 1D PULSE AMPLIFIER 38NP0168 RENE Figure 6 4 The AN SSW 1D E data terminal set COMPUTER SELECTOR INPUT 1 DDC A INPUT 2 DDC B INPUT 2 DDC A INPUT 1 DOC B COMPUTER COMPUTER COMP DDC COMP DDC DIGITAL TO DIGITAL CONVERTER A PO en DIGITAL TO DIGITAL CONVERTER B DDC OUTPUT CAINS ons c TEST DATA TERMINAL SET AN SSW 1D E The Link 4A data terminal set 15 the AN SSW ID E The data terminal set performs the following functions Provides overall Link 4A system timing Converts parallel data from the CDS computer into serial data for transmission to controlled aircraft Converts serial data received from controlled aircraft into parallel data for input to the CDS computer The current five ver
55. for external function operations The normal position for this switch is dependent on the configuration of the system on your ship NET MODE SWITCH The NET MODE switch determines the mode of operation of the DTS The modes are BC or broadcast SHORT BC ROLL CALL NET SYNC and NET TEST DATA RATE SWITCH The DATA RATE switch determines the speed and frame timing operation of the DTS When the switch is in the 1364 9 09 position the DTS transmits and receives data at 1364 bps The data frame phase identification interval is approximately 9 09 milliseconds When the switch is in the 2250 position the DTS transmits and receives data at a rate of 2250 bps and a frame interval of 9 09 milliseconds When the switch is in the 1364 1 8 18 position the data rate is 1364 bps but the frame phase shift interval is increased to 18 18 milliseconds OWN STATION ADDRESS SWITCH The OWN STATION ADDRESS switch consists of two thumb wheel switches in which an address is entered to identify the address the DTS will respond to as its own In the roll call mode and with the DTS configured as a picket station the DTS will transmit its tactical data when the interrogation message address matches the address entered into the OWN STATION ADDRESS switches RANGE IN MILES SWITCH The RANGE IN MILES switch also consists of two thumb wheel switches These switches are used to select the approximate distance between the net control station and t
56. frequency is shifted The primary ad vantage of PSK 15 that it can be accomplished in an am plifier stage Pulse Modulation Pulse modulation is accomplished by varying the characteristics of a series of pulses This can be done by varying the amplitude duration frequency or posi tion of the pulses It can also be done through coding Pulse modulation 15 especially suited for use with com munications systems incorporating time division mu tiplexing BASIC TRANSMITTERS Remember transmitters are generally divided ac cording to their type of modulation In the discussion below we describe very briefly how each type oper ates to help you differentiate between them CW Transmitter A basic CW transmitter 15 shown in figure 1 3 CW is one of the oldest and least complicated forms of communications Two advantages of CW are a narrow bandwidth which requires less power out and clarity even under high noise conditions The major disadvan AAAA ANANN VVVUVUY VUVUVUVV _ BUFFER FREQUENCY MULTIPLIERS OSCILLATOR AMPLIFIER SUPPLY ec RE Figure 1 3 Continuous wave transmitter tage of a CW transmitter is that it must be turned on and off at specific intervals to produce Morse code keying dots and dashes This method is very slow by modern day standards A better method of transmitting is AM AM Transmitter Figure 1 4 a block diagram of an AM transmitter
57. in the main communications spaces generally in the vicinity of the technical control working area The switchboard equipment group interconnects crypto and plain subsystem equipment with the appropriate radio equipment You should recall front chapter 1 that these switchboards are also the interconnecting points for other subsystems within the overall exterior communications system Therefore they are not unique to the SAS Transmit and Receive Radio Equipment These equipment may be located in both the main communications spaces and in separate rooms located in various parts of the ship This equipment group consists of the various transceivers transmitters and receivers used for voice nets The more common transceivers you will encounter are the AN SRC 20 series AN VRC 46 AN WSC 3 V 3 and V 7 AN URC 93 and AN WSC 6 Common transmitters include the AN URT 23 AN URT 24 T 1322 SRC and AN GRT 21 Common receivers are the R 1051 series R 1903 and AN GRR 23 For additional information on individual equipment refer to that equipment s technical manual TELETYPEWRITER FACSIMILE EQUIPMENT In we discussed different methods of voice communications Sometimes the message 15 too long for practical transmission by voice so to get your message or idea across you may need to use a chart map or photograph Teletype tty and facsimile FAX equipment allow us to do this In the following paragraphs we will discuss some common t
58. into seventy 200 usec time slots that contain the sync preamble the data bits and the transmitter un key signal TRANSMIT KEYING SIGNAL CARRIER ON CARRIER OFF TRANSMIT FRAME 14 MS SYNC PREAMBLE 56 DATA BITS GUARD ENC BURSTS SKHZ INTERVAL SYNC BIT 2004S MESSAGE NUNN NNN MESSAGE OUTPUT UN KEY SIGNAL LOGIC ONE LOGIC ZERS CONTROL MESSAGE VIZI31415 6171819 10111112 2 314 5 6 7 8 7 BIT NUMBERS CONTROL DATA 1 213 4 BIT NUMBERS 10 000 BINARY DIGITS PER SECOND L GUARD INTERVAL Figure 6 2 The Link 4A control message format leajeo 7o 54 55 56 Sync Preamble The sync preamble is made up of the first 13 time slots of the control message The first eight time slots each contain one cycle of a square wave consisting of 100 usec in the 0 state and 100 usec in the 1 state These eight time slots are known as the sync burst Following the sync burst are four time slots in the 0 state called the guard interval The guard interval indicates the changeover to the 200 usec data signals Time slot 13 is the start bit and is always a 1 Data Bits The Link 4A message data is contained in the 56 time slots slots 14 through 69 that follow the sync preamble Each time slot contains one data bit The first 13 bits of this data is a binary number that indicates the address of the particular aircraft Only the a
59. is to be aboard a ship Submarine aircraft or shore installation In this chapter we will limit our discussion primarily to commonly used shipboard and shore equipment Satellite Communications Terminal AN FSC 79 The AN FSC 79 terminal processes and converts 70 MHz signals to X band shf transmitted signals It also converts received signals from X band to 70 MHz This terminal can simultaneously transmit a spread spectrum carrier and receive a satellite beacon signal The design of the terminal provides redundancy in many components to ensure a high degree of availability The terminals are installed at NCTAMS LANT MED WESTPAC EASTPAC and NCTS Stockton contractor operated Uhf Transceiver AN WSC 5 V The AN WSC 5 V transceiver provides an eight circuit full duplex data operation or as an alternative six full duplex data circuits and two FM audio or tone group circuits It also provides an interface for connectivity to the uhf DAMA E c XEM M M M LM uu I LI Figure 3 20 Uhf transceiver AN WSC 5 V equipment Figure 3 20 shows an AN WSC 5 V transceiver installation This transceiver is capable of three types of modulation demodulation Frequency modulation demodulation with pre emphasis de emphasis for voice transmission reception Frequency modulation demodulation without pre emphasis de emphasis for tone group transmission reception e Differentially encoded phase shift keying
60. of reference rather than wpm is used Bit In binary signals the term bit 1s equivalent to one place in a binary number Because of the influence of computer language modulation rate is sometimes expressed as bits per second bps When it is expressly understood that each unit in the baudot character 18 the same length the modulation rate expressed in bps is the same as the modulation rate expressed in baud DC CIRCUITS The two most common methods of creating the mark and space conditions are neutral and polar operation In neutral operation current flow represents the mark and no current flow represents the space In polar operation current impulses of one polarity represent the mark and impulses of the opposite polarity represent the space Neutral circuits use the presence or absence of current flow to convey information These circuits use high level 60 20 milliamperes as the line current value Low level operation uses 6 vdc at 20 micro amps and can be balanced or unbalanced A neutral teletypewriter circuit consists of a transmitting device a current source a variable resistor to control current a receiving device and a transmission line Polar operation differs from neutral operation In a polar system information is always present in either a positive or negative condition The circuit composition is the same but polar operation requires an additional current source This current source is usually a solid st
61. of one nickel cadmium NiCad battery and two lithium sulphur dioxide cells The NiCad battery will provide power to critical components during short power failures The lithium sulphur dioxide cells supply power to the chronometer The Interface Unit controls the communications between the JTIDS terminal and the host computer and provides amount for the Secure Data Unit SDU On shipboard systems the C2P is the host computer The Subscriber Interface Computer Program SICP is a software program that controls the communications with the host computer and provides the data processing necessary to integrate the terminal and the host computer The IU and SICP also provide M t Host Avionics Prison DE Audio alt a an E nlsi aa oum 1 ee eee E WOA anan LLITI 9 LITT 1 meee EERI Li LECT C2P 38NP0180 fo ee ee eee eee eee eee 500 kHz TACAN Control the following functions analog to digital and digital to analog conversion of voice signals feed through interface between the DDP and the SDU and primary and backup power interface The IU also provides the interface for receiving and supplying the TACAN blanking pulses These blanking pulses prevent the TACAN and the JTIDS terminal from transmitting at the same time The Digital Data Processor DDP
62. one user accesses a file all the other users are prevented from accessing that file until the first user is finished with it As you can see this method severely limits the number of users able to access the information Another method used to prevent data loss is record locking In a data base environment many users could access the same data file but when a record was being modified by one user the other users were locked out of the record being modified A data file can be updated by several users without threatening the integrity of the data by using this technique Although the disk server was used in most LANs developed before 1985 a major problem still existed in maintaining data integrity The two methods covered in the previous paragraphs provided for data management but not for reliable disk management A disk drive stores information on the next available block on the disk When the disk server was used it was not uncommon for two users to try to write data to the same block at the same time When this happened the second user would overwrite the data just written by the first user causing a loss of data The development of the file server in 1983 solved all of the problems encountered with the disk server File Server Currently all local area networks require some type of file server In most cases the file server is a dedicated PC or minicomputer The file server performs the processing of the network control sof
63. or intercepts energy in the form of electro magnetic waves An antenna can be simply apiece of wire but in practice other considerations make the de sign of an antenna system complex The height above ground conductivity of the earth antenna shape and dimensions nearby objects and operating frequency are just a few of the factors affecting the radiation field pattern Information on antenna theory basic antennas and wave propagation will be available in Antennas amp Wave Propagation volume 7 of this training series Currently you can find information in Navy Electric ity and Electronics Training Series NEETS Module 10 Introduction to Wave Propagation Transmission Lines and Antennas NAVEDTRA 172 10 00 83 SYNCHROS AND SERVOS In many electromechanical systems the angular position of a shaft must be transmitted from one loca tion to another without an actual mechanical linkage You have seen examples of this in mast mounted rotat ing directional antennas and the automatic tuning func tion of receivers and transmitters from remote locations A widely used method employs ac machines that operate as single phase transformers These ma chines are called synchros Synchro receivers contain sets of gears that do the actual moving of the device to which the synchro 15 at tached These receivers are light duty devices de e gt 52 Poe e Vas ioe ao se SE S 2 i 55 45 eatery ee Pet
64. over the horizon targeting OTH T e Officer in Tactical Command Information Exchange Subsystem OTCIXS This subsystem continues to provide inter and intra battle group communications and is now also designated as the return path for ship to shore OTH T communications e Demand Assigned Multiple Access DAMA Subsystem This subsystem was designed to multiplex several subsystems or users on one satellite channel allowing more satellite circuits to use a single uhf satellite channel Control Subsystem This subsystem is a communications network that provides status reporting and management of system assets The installation of subsystem baseband equipment and rf terminals aboard ships is driven by communications traffic levels type of com munications and mission requirements For example Fleet Broadcast a common subsystem in naval com munications is received by many different types of ships Atypical suite on a large ship may include Fleet Broadcast CUDIXS NAVMACS Secure Voice TADIXS OTCIXS Teletypewriter and TACINTEL equipment Most subsystems have very rigid control and accountability of message and data link traffic AII subsystems have some form of backup mode Within the constraints of equipment capability each subsystem addresses the unique requirements of the user and the environment in which the user operates On board your ship you may not use all these systems but during your career you will probably c
65. portion of the transmission The TIMING switch on the TADIL A control panel must be in the CORRECTED position for both of these modes The INHIBIT position of this switch disables both the fast and continuous synchronization circuits of the DTS The DTS will maintain the time base that was stored when the switch was turned to INHIBIT For synchronization to be held the unit with its sync mode inhibited must maintain its original geographic relationship to all other units in the net This position is used when the received signal contains interference that could cause loss of synchronization OPERATE SELF TEST SWITCH This switch must be in OPERATE for normal on line operations When the switch is placed in the SELF TEST mode the DTS is placed in an off line mode and the fault isolation circuitry is enabled STATUS XMT DATA RCV DATA CODE ERROR ERROR ERROR BUSY 9 LO Ovo Q wa O OS SC lc NYY CONFIGURATION Ny COMPUTER STORED OPERATE CONTROL FY YOY V CONTROL CORRECTED JE PICKET be CORRECT TRANSMIT TRANSMIT VO 0G620 X LABEL RESET INITIAT NET MODE DATA RATE ROLL CALL 2250 Figure 4 16 The AN USQ 59 TADIL A control panel CONTROL ON OFF SWITCH When the CONTROL switch is placed to the ON position 28Vdc is applied to the fault isolati
66. power reduce the chance of interference and boost the sensitivity of the CONVERTER SWITCHBOARD AMARAT SB 973 SRR AN URA 17 OR CV 2460 D C PATCH PANEL SB 1203 UG SB 1210 UGQ gt REPERFORATOR ETV30016 Figure 2 4 Lf receive 2 5 receiving system With the path length and direction fixed propagation factors are simplified This provides highly reliable hf communications Ship to Shore High frequency atmospheric communications between shore stations are relatively easy because shore stations have sufficient space for efficient omnidirectional antennas or arrays that provide hf coverage of large areas Ship to shore hf communica tions are more difficult because the ship is moving and constantly changing direction This change of direction and severe space limitations aboard ships make the installation of large efficient hf antennas impractical To overcome these problems ship to shore systems have two major differences from point to point systems First shipboard antennas are omni directional Second several frequencies are usually assigned for each circuit If one frequency starts to drop out another can be selected to match the propagation path conditions between the ship and the shore terminal Ground to Air The use of hf radio for ground to air com munications is similar to its use for ship to shore
67. reference frame of a Link 11 header performs which of the following functions Serene 1 Provides synchronization between the DTS and the CDS computer 2 Provides a time reference for the DTS 3 Provides a time reference for the radio 4 Provides the reference to extract the data in the next 295995 frame During a receive cycle the start code causes which of the following actions 1 The CDS computer to send the prepare to receive data interrupt 2 The DTS to send the prepare to receive data interrupt 23553 3 The CDS computer to send the prepare to transmit data external function 1 The DTS to send the prepare to transmit data interrupt Exactly how many data bits are contained in each Link 11 information frame Tha Ace 2 24 Du xU 4 32 3 40 The control stop code is generated by which of the following units Ll NCS Only 2 Picket station only Hither NCS or a picker station indicating the end of a control message 14 During a receive cycle the stop code control or picket causes which of the following actions 1 The CDS computer to send the end of data interrupt 2 The DTS to send the end of data external function 3 The CDS computer to send the end of receive interrupt 4 The DTS to send the end of receive interrupt A Or Interrogation message consists of a total of how many frames 1 Five 2v 9 3 Seven 4 Eight The two frames following a control stop code indica
68. serial pulse trains into parallel data and sends the data to the CDS computer In a typical aircraft carrier system the four distinct modes of operation in the Link 4A system are intercept vectoring air traffic control automatic carrier landing system and precision course direction Intercept Vectoring Intercept vectoring enables the controlling ship to guide an aircraft to an intercept point The two types of data sent to the aircraft during intercept vectoring are command data and situation data Command data provides direct steering and control information whereas situation data provides the aircraft with an overall picture of the tactical situation with respect to its target This data is used to guide the aircraft within striking range of its target at optimum position and altitude for an attack The messages also contain instructions to the pilot such as target identity break engagement and return to base 6 2 Air Traffic Control In the air traffic control mode Link 4A is used to control the aircraft in the carrier s traffic pattern The control station transmits data to the aircraft to maintain safe flight patterns and assigns priority for landing approach As each aircraft enters the landing pattern it is transferred to the automatic carrier landing system for final approach and landing Automatic Carrier Landing System The automatic carrier landing system selects aircraft in the order of priority from th
69. shows you what a simple AM transmitter looks like The microphone converts the audio frequency input to electrical energy The driver and modulator amplify the audio signal to the level required to modulate the carrier fully The signal is then applied to the power amplifier pa The pa combines the rf carrier and the modulating signal to produce the AM signal for trans mission FM Transmitter A block diagram of an FM transmitter is shown in figure 1 5 The transmitter oscillator is maintained at a constant frequency by a quartz crystal This steady sig nal is passed through an amplifier which increases the amplitude of the rf subcarrier The audio signal is ap plied to this carrier phase shift network Here the fre quency of the carrier shifts according to audio signal variations The FM output of the phase shift network 18 fed into a series of frequency multipliers that increase the signal to the desired frequency The signal 15 then amplified in the power amplifier and coupled to the an tenna Two important things to remember are 1 the amount of variation from the carrier frequency de pends on the magnitude of the modulating signal and 2 the rate of variations in carrier frequency depends on the frequency of the modulating signal The FM transmitter is better than an AM transmit ter for communications purposes because FM is less affected by static and other types of interference An even better transmitter is the
70. signals transmitted on a single path 1 Modulation 2 Single audio mixing 3 Multiplexing SsSplrttEigng 1 44 Which of the Following cations methods involves subdividing a channel into smaller segments of equal size and placing a signal in each subchannel FDM TDM DEM DTM A GOS N Fe Which of the following requirements does SAS satisfy 1 Nonsecure voice communications 2 Secure voice communications 3s Signal switching 4 All of the above How Many crypto and plain subsystems are used within SAS Five Two Three Four HY GO One mode of teletypewriter operation is the synchronous mode What other mode is used for basic teletypewriter operation Asynchronous Bisynchronous Nonsynchronous Trisynchronous Hm CO BO ee What 1S the name of the five unit code that includes mark and space signals and is used in teletypewriter operation 1 Baud 2 Baudot ASCEL 4 Morse iE sor 4 7 Which of the following problems 15 reduced by not using start and stop signals in the synchronous teletypewriter mode Converted signal Delayed signal Distorted signal Lost signal d CO N Fe Which of the following terms accually pertains only to modulation rate Baud Words per minute Bites per second Words per second Hm CO DO Fe In neutral tty operation current flow and no current flow represent the mark and
71. single five drawer electronics cabinet as shown in figure Antenna A A YT B Link 16 Link 16 TransmiU Q of Net TET Digital Data Processor Group JTIDS Terminal Receive Cee Receiver Transmitler D Receiver Transmitter Drawer 9 High Power r Amplifier T R __ pt Digital Data Processor Group Drawer FA E te gcc IE S o MI ET BE HURRY uum ERST WP WP n Power Interface Unit Drawers Figure 7 7 The AN URC 107 V 7 JTIDS data terminal 38NP0178 The components of the JTIDS terminal include the Digital Data Processor Group DDPG the Receiver Transmitter Group R T the High Power Amplifier Group HPAG and the Power Interface Unit PIU The Secure Data Unit SDU Receive 38NP0179 High Power Amplifier Group La LL SOES Figure 7 8 The JTIDS terminal functional block diagram 7 9 is a separate assembly that is mounted to the Digital Data Processing Group Figure 7 8 is the functional block diagram of the JTIDS terminal DIGITAL DATA PROCESSOR GROUP third drawer of the terminal houses the digital data processor group The two major components are the interface unit IU and the digital data processor DDP A battery assembly is mounted to the front of the DDPG drawer This assembly consists
72. so that the PU does not respond to interrogations j Directing all units TO change from a HF frequency to an UHF frequency 4 Removing the troubled PU from the polling sequence 4 18 until the problem is corrected and the troubled PU is ready to reenter the net When you set up the DTS to run a single station POFA the DTS must be configured to operate in which of the following modes 1 Simplex 2 Half duplex 3 Full duplex 4 POFA TEST mode 20 When you run a single station POFA with the radio set which of the following equipments is are NOT checked Security device 1 0 path Antenna coupler DTS to radio audio lines Radro LO DIS audro lines CO Fe Running single station can assist the technician in isolating a problem in which of the following sections of the DI 1 Receive timing 2 Doppler correction 3 DTS to antenna interface 4 Transmit timing D single station POFA should print the interrupts in what sequence 1 End of receive prepare to transmit prepare to receive 2 Prepare to receive prepare to transmit end of receive 3 Prepare to transmit end of receive prepare to receive 4 Prepare to transmit prepare to receive end of receive A single station POFA error printout that lists bit errors that are less than 10 percent of the total words transmitted is considered a successful POPA 1 True 2 False A single broken line in the Switchboard betw
73. space Tm polar vey operation what is the condition of the line current 1 Ts 2 It 4s 95 EE UG 4 TO ass absent positive negative present always always always always What device is used to change ety de pulses unto mark anad space signals to modulate the transmitter carrier wave Detector Keyer Modulator Transformer Hm CO DO Fe After the tty signal is received what device s must be used to change the signal back to pulses Convertor Receiver Both 1 and 2 above Hm CO BO Fe The Navy s two basic RATT systems are AFTS and RFCS is the RFCS system commonly called What 1 ASK Ze BOK D 4 ROR Ts T5905 ps What device provides looping jx current for the tty A solid state power supply 2 A generator 3 An alternator 4 tty battery What is are used to interconnect 1 54 all the tty equipment in any configuration needed 1 Multiple cabling 2 Wire runs 3 TTY panel 4 Switching resistors Which of the following methods is are used to reduce fading and interference in long range communications 1 Frequency diversity 2 Space diversity 3 Both 1 and 2 above 4 Ionospheric inversion What type of frequency diversity is used for multichannel broadcasts l 2 Space riple 4 Tone D ring umnmpatoenmsHg which plug from its tty panel jack first will p
74. status indicators are not displayed in real time They are updated approximately every 50 milliseconds The signal processing indicators are as follows XMT ADDRS OPERATOR ALERTS APPEAR HERE PRE PHA CC1 CC2 EOT NOIS D w ATA 20 02 24 06 41 22 31 43 12 24 32 36 36 16 10 04 30 23 15 21 77 ERROR MESSAGES APPEAR HERE Wen Ca Ra as um Raf ZDATA 1 REC 17 NCT 6 9 9s 38NP0202 Figure 5 9 The LMS 11 Status display LMS Should always be green e LSN Indicates that the LMS 11 is listening for the link audio e PRE Indicates that a preamble has been detected PHA Indicates that a phase reference frame has been detected e CCI Indicates the first frame of a control code CC2 Indicates the second frame of a control code e EOT lIndicates that the LMS 11 has detected the end of transmission NOIS Indicates that the received data frame did not pass the data quality test DATA Indicates that the LMS 11 has detected a data frame that has passed the quality test Note that the control codes and phase reference frames are also data frames e REC Shows the status of the raw record function of the LMS 11 The indicator will be green when the recording is turned on and red when the recording is stopped The last two fields of the status box indic
75. system State the purpose of the Joint Tactical Information Data System Link 16 Describe the components of the Link 16 system State the function of the Command and Control Processor C2P system Describe the components of the system THE AN USQ 125 DATA TERMINAL SET The AN USQ 125 data terminal set is the newest Link 11 data terminal set in the Navy It is quickly replacing older DTSs such as the AN USQ 36 and the AN USQ 59 There are several configurations of the AN USQ 125 The CP 2205 P V USQ 125 data terminal with the MX 512P RC Remote Control Unit configuration The other configuration is CP 2205 P V 2 USQ 125 data terminal with a personal computer 386 or better running the MXPCR software The personal computer serves the same function as the remote control indicator in this configuration The standard interface configuration of the AN USQ 125 is shown in In this chapter we examine the data terminal and the functions of the control indicators either the MX 512P RC or a personal computer 7 1 Digital Wire Line ee QCA TYSCNKRA VFA TUWUIVI AN USQ 125 Data Terminal HF UHF Radio 38NP0172 Figure 7 1 AN USQ 125 data terminal set standard interface block diagram THE CP 2205 P V USQ 125 DATA TERMINAL The CP 2205 P V USQ 125 data terminal is a compact state of the art data terminal that is mounted in a standard 19 inch equipment rack The data 38
76. tactical information Broadcast When the broadcast mode is used one PU will continuously send a series of data transmissions to all the members of the net Once manually initiated the transmission will continue to be sent automatically until the operator manually stops it Through the use of the broadcast mode other picket stations can receive real time tactical information without breaking radio silence Short Broadcast In the Short Broadcast mode a picket station or the NCS sends a data transmission to the other members of the net The transmission is initiated by the operator depressing the TRANSMIT START button on the DTS control panel and is terminated automatically when the computer has finished sending the DTS data This mode is used only when no other unit is transmitting Radio Silence In the Radio Silence mode the radio set key line and the data terminal set audio output are disabled The receive capability of the DTS is not affected The Radio Silence mode is manually initiated and terminated BUILDING A LINK 11 MESSAGE Information transmitted from the DTS originates from two sources Tactical data always originates from the CDS computer Other information including the preamble phase reference start and stop codes and address frames originates within the data terminal set These additional special purpose frames are added to the data frames to form the proper messages For the DTS to control the net
77. the CDS computer a data terminal set a communications Switchboard and a radio transceiver The CDS computer outputs parallel digital data to the Link 4A data terminal set Currently the data terminal set most shipboard installations use is a type of the AN SSW 1 U It will be designated as the AN SSW IA B C D E U The data converts the computer data into a serial time division multiplexed pulse train that 15 transferred to the radio terminal set transceiver through the communications switchboard The communications switchboard connects the selected UHF transceiver to the data terminal set The radio transceiver converts the pulse train into FSK variations in the carrier signal frequency After the aircraft receives the transmitted data it may respond by transmitting data to the controlling lt lt 11 7 bp oB 32060 U 30 BIT DIGITAL DATA TRANSFER coll POS SWITCHBOARD AN UYK 7 OR Pad CP 642B USQ 20 AN SSW 1 F RAIDIO NTDS COMPUTER ae ei DATA TERMINAL SET TRANSMITTER um LINK 11 Le DATA TERMINAL 38NP0165 o m 4 Co 5 Figure 6 1 The shipboard Link 4A CDS system station This is the reception cycle The receiver removes the carrier frequency and forms the serial data pulse train The pulse train is sent to the data terminal set via the switchboard The data terminal set converts the
78. the Link 11 system These are the single station POFA used to check components of the Link 11 on board a single station and the multi station POFA used to check the connectivity of several units SINGLE STATION POFA The single station POFA is an end around test that transfers canned data from the computer through the crypto device and the data terminal The single station POFA can also be run through the radio set to check out part of the audio communications path further POFA Setup The POFA is a special program that is loaded into the computer It is very important that you follow the instruction manual when attempting to run the POFA The POFA is designed to run in full duplex mode Normal link operations use the half duplex mode Full duplex means the system is configured to 5 3 transmit and receive data at the same time In the DTS this is accomplished by the transmit audio being fed directly into the receive input Also if the DTS 15 operating in full duplex mode the rest of the system especially the crypto device must be in full duplex On the KG 40 full duplex is accomplished when the front panel switch is turned to the POFA TEST position Analyzing Single Station POFA When a single station POFA is completed a printout of the results 1s produced To analyze this printout properly the technician must understand 38NP0194 without radio Figure 5 1 Single station POFA configurations what equ
79. the flexible interconnection of incompatible systems using data communications facilities The OSI model does NOT define anyone vendor s particular network software as such nor does it define detailed standards for any given software It simply defines the broad categories of functions that each of the seven layers should perform The OSI model can include different sets of standards at each layer that are appropriate for given situations For example in a very simple data communications system one that RECEIVING DEVICE TRANSMITTING DEVICE PRESENTATION 2 PRESENTATION LEVEL LAYER LEVEULAYER SESSION LAYER SESSION LAYER TRANSPORT LAYER LEVEL NETWORK LAYER NETWORK LAYER 2 DATA LINK LAYER 2 DATA LINK LAYER HARDWARE LEVEL PHYSICAL LAYER ad 5555 MUNICATION CHANN EL gt gt 533333 38NPO185 Figure 8 1 OSI model showing the seven layers gt 60 D m 2 gt m D 2 gt Ww S zo gt a uses a simple point to point link the software at the higher level layers say 5 6 and 7 might be very simple or possibly nonexistent However in a very complex data communications system all seven software layers may be implemented Although there is no requirement for any hardware or software vendor to adhere to the principles set forth in the OSI model there is a worldwide trend in the computer industry t
80. the receiver switchboard is sent to the C 1138 radio set control and SB 988 SRT HANDSET arm AMP th T Figure 2 7 Vhf transmit and receive system fed to a handset The voice signal also can be sent from the switchboard to an AM 3729 remote speaker amplifier and then to a speaker This allows the user to listen to the signal without having to hold the handset VERY HIGH FREQUENCY COMMUNICATIONS The Navy uses the very high frequency vhf band for mobile communications such as bridge to bridge among boat crews and for amphibious operations and landing parties Vhf Transmit A typical vhf transmit and receive system is shown in figure 2 7 On the transmit side the operator at a remote location talks 1nto the handset The handset 15 connected to radio set control C 1138 The radio set control output is fed to transmitter transfer switchboard SB 988 SRT The switchboard performs the same function as it does in the If and hf systems The output of the switchboard is connected to the transmit side of the transmitter receiver transceiver AN VRC 46 or AN VRC 80 The transceiver converts the input signal to an rf signal for transmission and the rf is radiated into the atmosphere by the antenna Vhf Receive Again look figure 2 7 The incoming signal is picked up by the antenna This signal is fed to the receive side of the transceiver
81. the transmitter during tty operation Voice communications also can be connected to the SB 988 SRT switchboard The voice communications are developed at a handset connected to the C 1138 radio D C PATCH D C PATCH EUR TELETYPE L PANEL FL EET PANEL ___p RED BLACK L LIFAU NAT VEE SB 1203 UG AN UCC 1 OR CV 2460 ee I E AAITEAIAIA TRANSMIT TRANSMITTER MEME _ TRANSFER TRANSMITTER 7 CONTROL TELETYPE I TELETYPE SWITCHBOARD 1004 _ ew SB 988 SRT AN URT 23 AN ISRA 17 AN URA 38 po OR RADIO AN SRA 56 57 58 4 M HANDSET CON TROL ETV30017 C 1138 Figure 2 5 Shipboard hf transmit system pali wa m ANTENNA RECEIVER eee RADIO TA PATCH RECEIVER TRANSFER SET SET PANEL SWITCHBOARD CONTROL R 1051 URR OR SB 973 SRR 1138 2368A URR R 1903 URR 1 J TELETYPE SPEAKER AMPLIFIER LA HN 5 p M __ TELETYPE RECEIVER eum H PATCH PANEL re PANEL E AN UCC 1 SB 1203 UG SB 1210 UGQ HEPEREOHAT R ETV30018 Figure 2 6 Shipboard hf receive system set control The output of the radio set control is then fed to the switchboard RECEIVER TRANSMITTER
82. to end flow control and window management Session Layer The session layer allows users on different machines to establish sessions between one another It performs the functions that enable two or more applications to communicate across the network performing security name recognition logging administration and other similar functions Unlike the network layer this layer is dealing with the programs in each machine to establish conversations between them as follows e Allows two applications processes on different machines to establish use and terminate a connection or session Performs synchronization between end user tasks by placing checkpoints in the data stream so that if the network fails only the data after the last checkpoint has to be retransmitted Provides dialogue control who speaks when how long and so on PRESENTATION LEVEL LAYER The presentation level consists of the presentation layer The presentation layer formats data to be presented to the application layer It can be viewed as the translator for the network This layer provides a common representation for data which can be used between the application processes The presentation layer relieves the applications from being concerned with data representation providing syntax independence as follows Encodes data in a standard way integers floating point ASCII and so on Provides data compression to reduce the number
83. to have some knowledge of the Link 11 modes of operation and how the messages are formed Link 11 employs networked net communications techniques for exchanging digital information among airborne land based and shipboard systems As you have seen the amount of hardware required to support Link 11 operations is however establishing and relatively small maintaining a successful link can be very complex 4 5 Establishing a Link 11 Net The establishment of a successful link involves the interaction and teamwork of the operators and technicians of several units working toward the common goal If one unit is having trouble with the link radio data terminal set or other equipment it can make the entire link unreliable When a task force is about to deploy the task force commander will issue a message that has the necessary information required to establish Link 11 communications The information in this message includes a list of primary and secondary frequencies designation of the initial net control station initial gridlock reference unit GRU designation PU identification and addresses initial data link reference point DLRP and other required operating procedures Voice communications are also required for net control and coordination during initialization When the task force 1s formed the picket stations inform the net control station NCS of their readiness to establish link operations Upon establishing com
84. to make sure each workstation has fair and equal access to the network The access method used is governed primarily by the topology and the protocol of the network The principal access methods are contention and token passing Contention The contention method features Carrier Sense Multiple Access CSMA and Carrier Sense Multiple Access with Collision Detection CSMA CD The CSMA CD method is shown in figure 8 6 Access for both is on a first come first served basis The CSMA access scheme is very similar to that of a citizens band CB radio Stations with data to send listen to the channel and wait until it 15 clear to transmit With CSMA CD when two or more workstations transmit simultaneously their messages will collide As soon as a workstation detects a collision it ceases transmission monitors the network until it hears no other traffic and then retransmits Most contention networks assign a unique retry algorithm to vary the wait and retry period This algorithm reduces the likelihood that after a collision two workstations will transmit retries simultaneously Token Passing Token passing is an orderly access method and is shown in figure 8 7 Each workstation passes on the Opportunity to transmit to its closest neighbor until a station is found with a message to send This permission to transmit is called a token When a workstation with data to send is handed a token part of the token is changed indicating it is
85. typical CUDIXS installation NAVMACS is a shipboard message processing system that automatically guards a minimum of four broadcast channels serves as an automated shipboard terminal for CUDIXS and provides accountability for all incoming and outgoing message processing needs for ships of the fleet INTERCONNECTING GROUP PROCESSOR MAGNETIC TAPE UNIT RECORDER REPRODUCER MAGNETIC TAPE CONTROL UNIT MAGNETIC DISK CONTROL UNIT MAGNETIC MAGNETIC DISK DISK DRIVE POWER RUE REMOVABL P E SUPPLY EE VIDEO ISPLAY ETV30041 SWITCHING UNIT TERMINAL NAVMACS subscriber terminal equipment is similar to CUDIXS terminal equipment The NAVMACS program is designed to address the growth requirements in existing installations and the unique requirements of ships having a high volume of message traffic In ships that have a message pro cessing and distribution system MPDS the NAVMACS processor interacts with the MPDS pro cessor A basic NAVMACS system is shown in fig NAVMACS reads the headings of incoming message traffic and separates all messages addressed to the ship or commands for which it is guarding The system compares every addressee on each incoming first run message against entries in its command guard list CGL When the system finds one or more matches between addresses on the first run message and the entries of the CGL the message is printed copied onto a line p
86. used solely for serving the network and is NOT used as a workstation it is referred to as a dedicated a workstation it is referred to as a nondedicated server If the server can also be used as server Some networks do NOT have a single dedicated file server Instead they use a distributed approach in which any of the nondedicated servers may make available files that reside on their hard disks Under these circumstances any workstation on the network can use or copy these files Moving files back and forth on such a network establishes a temporary relationship you might say between the two PCs involved One PC acts as the server and the other PC acts as the receiving workstation Print Server The print server is a software routine that allows all the workstations on the LAN to use a single printer When the laser printer was introduced to the market the extremely high quality print and multiple fonts made it desirous for all correspondence Unfortunately the cost of a laser printer often exceeded that of an individual workstation and made it impractical for each workstation to have a dedicated printer The print server solved that problem by accepting requests for print jobs from the network users and directing them to the printer The print server makes sure one job is completed before a new job is started Print server routines are included in almost all network operating systems on the market today WORKSTATIONS Wor
87. using the OM 43A USC modem The transceiver has a 70 MHz interface for connection to either the modem or the TD 1271B U DAMA multiplexer All four NCTAMS transceivers installed have AN WSC 5 V The C 11330 WSC 5 V shown in figure 3 21 provides for remote control of the AN WSC 5 V for teletype operation The C 11330 WSC 5 V 18 similar to the C 9899 WSC 3 except that it uses 6 for the 3 24 keyline signal and indicator lamps Both units have identical front panels Transceiver AN WSC 3 V To be consistent in this discussion we will refer to both the AN WSC 3 and AN WSC 3 V transceivers REC XMIT ON ETV30059 Figure 3 21 Control Indicator C 11330 WSC 5 V or C 9899 WSC 3 Figure 3 22 Uhf radio RT 1107 WSC 3 as AN WSC 3 A single AN WSC 3 RT 1107 WSC 3 is shown in figure 3 22 The AN WSC 3 transceiver is used primarily aboard ship at Marine Corps terminals and at selected shore installations It has various configurations designed to meet the particular requirements of these platforms The configuration differences are identified in the AN WSC 3 variations table E FK A5 2400 T T Maru MODULAHION PATA SAT COM CARRIER SIGNAL 22 Ong ON ACQUIREG The transceiver can be operated in either satellite or line of sight mode either locally or remotely A modulation control permits selection of PSK
88. will transmit Net Test Mode The Net Test message consists of the five frame preamble the phase reference frame and the Net Test words generated by the DTS When all the Net Test words in the library have been transmitted the sequence starts over until the operator stops the Net Test LINK 11 DATA TERMINAL SET DTS As you have seen the data terminal set 15 the heart of the Link 11 system The DTS performs the modulation demodulation and control functions required for proper Link 11 operation It accepts data from the CDS computer in the form of 24 bit data words adds six bits of error detection and correction EDAC data and converts all 30 bits into an audio tone package that is sent to the transmitter portion of the radio set The key line signals necessary to Figure 4 13 Broadcast mode message format control the transmit and receive states of the radio set are also generated by the DTS Data received from the upper sideband USB and lower sideband LSB portions of the radio set receiver in the form of audio tones 15 converted into parallel binary data and sent to the CDS computer Currently several design generations of Link 11 data terminal sets are used in the fleet These include the AN USQ 59 and 59A the AN USQ 63 and the AN USQ 74 Originally introduced in the early 1960s each successive generation of the Link 11 data terminal set reflects additional knowledge gained from fleet use and advances in techno
89. 12 iN 11 3 LB po 30 7 CM 5 1 KG 100120800 wd T BATTERY TAI 7 9 IN 20 1 CM 89 975 MHz frequency range and contains a built in COMSEC capability that is compatible with VINSON KY 57 58 equipment Frequency hopping is an advanced method of ECCM Electronic Counter Counter Measure You should remember that a standard FM transmission 1s centered on a specific carrier frequency which means it can be easily detected monitored or jammed In 10243 0400 BACKPACK HARNESS 10012 0241 ANTENNA 10 10012 0201 1 3 1 CM BLADE ANTENNA f 1 6 LB 0 73 KG K H m 1218 90 0 0 54 EN 1 1 M LD H Ne H 189 GR 7 9 IN 5 2 2 5 10 24 THREAD SIZE 2 3 IN 5 8 CM 10012 9600 IP ADAPTER Figure 2 25 Transceiver AN PRC 117 2 27 frequency hopping no single carrier is used Instead the transmitter hops around the band in a random pattern spending only a few milliseconds on any one frequency This makes the signal difficult to detect and extremely difficult to monitor or jam AN PSC 3 Backpack radio set AN PSC 3 15 a portable battery powered half duplex uhf transceiver operat ing in the 225 0 to 399 995 MHz range It provides two way voice secure and plain and data com munications via satellite relay SAT or line of sight los modes Radio
90. 213 4 5 68 7 8 9 13 44 15 16 17 54 55 55 REPLY MESSAGE BIT NUMBERS 1 4 14421 4 L GUARD INTERVAL NOISE BURST REPLY DATA BIT NUMBERS 38NP0167 6 4 TEST MESSAGES During Link 4A operations the controlling station sends test messages at periodic intervals to the data terminal set for testing the message processing and display circuitry of the aircraft being controlled The test messages also check the data terminal set and its interfaces universal test message UTM and monitor control and reply messages MCM MRM The two types of test messages are Universal Test Messages Universal test messages UTMs are Link 4A control messages that are always addressed to a particular universal address and contain fixed specific information in each data field The UTMs provide the controlled aircraft with a means to verify proper operation of the link Monitor Control and Reply Messages Monitor control messages MCMs are Link 4A control messages that are sent to the data terminal set from the CDS computer to initiate internal testing of the data terminal set After the data terminal set completes its self check the MCM is transmitted with the universal address Depending on the equipment configuration of the aircraft the MCM will either be rejected or processed as a UTM The monitor reply message MRM is sent to the CDS computer upon the successful processing of the MCM The MRM is
91. 27 chapter 3 Which of the following radios is particularly useful during tactical black out operations 1 AN PRC 96 2 AN PRC 104 3 AN PRC 117 4 AN PSC 3 Which of the following radios has frequency hopping capaebDilrcty 1 AN PRC 96 2 AN PRC 104 3 AN PRC 117 4 AN PSC 3 The use of frequency hopping has certain advantages One advantage is that the signal is difficult to detect How is this accomplished 1 No single carrier is used 2 No modulation is used 3 No signal amplification is used 4 No multiplexing is used One important feature of the AN PSC 3 uhf radio is that it can interface directly with vhf radios What is the purpose of this interface 1 To provide a satellite link for radios 2 To make everyone use uhf instead of vhf 3 To provide a keyer for the vhf radios 4 To provide dual channel capability for the vhf radios Za ae DMDG messages are sent at 300 or 1200 baud in the satellite mode and 266 6 baud when connected to AN PRC 70 74 When these messages are received they are read ona display screen Which of the following is the device used to type and read these messages KY 823 P KY 798 P KY 283 P KY 879 P Hm CO BO rmm What system was specifically designed to provide solutions to equipment planning by automatically determining the best system that each participant in a communications link should use CLEPS CoD CLWPS Hm CO
92. 4 The waypoint data 28 Deux JSA The CAINS alignment and waypoint data is initially loaded into the aircraft using which of the following methods 1 Hard wired deck edge outlet boxes only 2 UHF RF transmission only 3 Either hard wired deck edge outlet boxes or UHF RF transmission 4 HF transmission only Ihe standard CDS control message is a 2 14 milliseconds in duration while the reply message is 14 18 milliseconds in duration 1 a 2 o 14 2 a 2 18 3 a 14 b 14 4 a 14 18 The CAINS receive cycle duration is equal to what total number of milliseconds ds 2 4 Sa 14 4 189 The transmit frame is divided into what total number of 200 usec time slots le do Zu 96 3e d 200 What total number of time slots make up the sync preamble of each transmit frame De 13 Zo A 4 70 What total number of transmit frame time slots contain message data bits 9525 22 05 Which of the following transit frame signals causes the transmitter to turn off and starts the receive cycle otop pulse OVAC DUESE Guard interval Transmitter un key H GC e The reply message contains what total number of data time slots duc Lo Zg UE 3 56 4 70 Which of the following Link 4A test messages is used to provide aircraft with the means to verify proper operation of Link 4A The monitor reply message The monitor
93. 4 bit word and places it on the input data lines along with the two error detection and correction bits Once the data is placed on the input data lines the DTS sets the input data request IDR line The computer will sample the data and send an IDA This process repeats for all frames of the message The first frame of the stop code is also treated as a message frame and sent to the CDS computer When the DTS recognizes the second frame of the stop code it will place the end of receive Call Indicator Figure 4 18 An address selector module interrupt on the input data lines and set the interrupt line The interrupt is then processed by the CDS computer and the input buffer is closed If the received stop code is a picket stop code the DTS simply resets itself If the stop code is a control station stop code the DTS will compare the next two frames received with its own station address code CDS Computer Output Transmit Data Cycle The output data cycle is initiated when the DTS detects its own station address either in an interrogation message or at the end of an NCS report and interrogation message When the DTS recognizes its own station address it starts to transmit the preamble During the first frame of the preamble the DTS sets the prepare to transmit interrupt on the input data lines The computer samples the interrupt and sends an IDA to acknowledge receipt of the interrupt The DTS finishes sending the pr
94. 42 WSC provides a means to monitor and test all functions The SB 4124 WSCs data 14 Bie sx ey St 9 _ a s5 di qie q 9 9 Ore ote LI mast uy J d Ginn 9 e e 1 4 4 4 POWER PANEL gt il MX 10342 WSC SB 4124AVSC p TD 1271B U i P 9 9 a 5 9 i ETV30079 ater ng Figure 3 41 EHlectrical Equipment Cabinet CY 7971 WSC e det o B aem m A Fi 9 a e w 4 F bei 1 s ad m Mere MAE Pu RS QE ets Letti Pes i s os X ad 9 Figure 3 42 Control Monitor Group OK 481 V 2 FSC and control patching switchboards Since we discussed the multiplexer in depth earlier we will not go into detail here Control Monitor Group OK 481 V 2 FSC The Control Monitor Group OK 481 V 2 FSC is a part of the Navy uhf satellite communications system 3 35 This group provides for the interfacing of the TD 1271B U multiplexer the AN WSC 5 V and the baseband equipment used at DAMA shore installations It provides for rapid reconfiguration and monitoring of interfaced equipment using digital rf and monitor patching facilities It can accommodate up to 14 TD 1271B U s a
95. 718 U peg 454 V 2 7 WSC 455 asm Se _ DAMA m m deum SECURE CONTROL suBsvsTEM L 3H NARROABAND E ENCRYPTED DIGITAL dl 2400 BPS VOICE L I3 seno la _ m CLEAR ANALOG INTER pera VOICE ____ gt CONNECTING GROUP 4 swiTcH _ 4 ON143 v 4 USQ BOARD 9 gt I aupo gt 34 iia 4 AEN p TSEC KG 35 GE xxm Er SONE x l FE couvenrer Frcs cono oam GUAM amp 3333 0 6 G NOT USED IN DAMA MODE SECURE SUBSYSTEM i i OPERATOR Er anon LLL ILL AUI OSEVOCOM E SENE Figure 3 12 DAMA configured Secure Voice Subsystem e Supporting the control subsystem are NCTAMS NCTS the USAF Satellite Operations Center and contractor operated control facilities The key to controllability lies in having many points for sensing the status of subsystems and equipment operation Status data may be collected by operators or by special facilities or equipment There are many points within each subsystem where subsystem and equipment operational status is collected Also several subsystems systems have the ability to provide a printou
96. AGE FRAMES length varies Figure 4 8 The message data frames added to the Link n transmission STOP CODE The stop code is a two frame code that follows the data message in a Link 11 transmission and is shown in figure 4 9 There are two types of stop codes the control stop code and the picket stop code The control stop code is used in messages originated by NCS NCS report and indicates that a picket address code follows the stop code The picket stop code indicates to the NCS that the picket unit has completed its message transmission Both the control stop code and picket stop code cause the receiving DTS to send the End of Receive interrupt to the CDS computer LINK 11 MESSAGE FORMATS The formats of the messages transmitted by the Link 11 system vary with the mode of operation Roll Call Mode Messages In the roll call mode the unit designated as the net control station sends out two types of messages These are the NCS call up message interrogation and the NCS report message with interrogation A third message the picket reply message is sent by picket unit in response to interrogation messages PHASE REFERENCE Saar a We ne BRU Mee Ba STOP SAGE FRAMES length varies PREAMBLE Figure 4 9 The stop codes added to the Link 11 transmission CALL UP INTERROGATION MESSAGE This message shown in figure 4 10 consists of the five frame preamble the phase reference frame and th
97. AME PERIOD 1 386 SECONDS M RANGING LINK TEST RCCOW CONTROL USERS ORDER CONTROL WIRE ORDER WIRE ETV30049 Data Time Slots These are the time slots during which users transmit or receive data There are three segments of time slots in each frame designated A B and C Segment A may contain from one to five circuits B may contain from one to eleven circuits and C may contain from one to six circuits The number of circuits in each group depends on the baseband data rate the forward correction rate and the transmission burst rate as influenced by the radio frequency interference RFT environment Current Operation For communications on the eastern Pacific satellite a master control station is installed at NCTAMS EASTPAC This same pattern of DAMA equipment installations has been followed at NCTAMS LANT MED WESTPAC and NTCS Each master control station has multiple multiplexer installed and each TD 1271B U multiplexer can accommodate up to four circuits The number of multiplexer installed aboard each ship varies according to platform requirements Any DAMA equipped platform with full duplex capability can be designated a channel controller This capability provides an emergency backup for the shorebased master controller terminals A DAMA subscriber who is designated a channel controller will provide all the required CCOW functions for DAMA system control of a particular rf channel Op
98. AT satellites fail or reach the end of their useful life An exploded view of a UHF F O satellite is shown in figure 3 19 Communications Capability The uhf communications subsystem consists of receive and transmit antennas a low noise pre amplifier 25 and 5 kHz channel receivers and TELEMETRY AND COMMAND UHF ANTENNA TRANSMIT i UHF ANTENNA RECEIVE QAUM A Ee SUN SHIELD gt SHF TRANSMIT SENSORS AND RECEIVE HORNS ETV30056 SOLAR CELLS Figure 3 18 LEASAT satellite 3 22 transmitters and an output multiplexer The shf communications subsystem provides shf anti jam up link capability for Fleet Broadcast which is down linked as uhf and consists of receive and transmit antennas the receiver a dual channel processor and the beacon transmitter Signals received by the shf receive antenna are fed to the shf receiver In turn the processor provides Fleet Broadcast outputs that are fed to uhf communications subsystem for down link The multiplexed anti jam broadcast capability of the UHF F O permits up to three broadcast channels to be up linked and down linked simultaneously On the fourth and subsequent satellites deployed an ehf communications subsystem will provide three ehf broadcast channel up links and seven ehf communications channel up links Each of these ehf up links will be capable of being down linked as ehf only uhf only or simultaneously as uhf and ehf U
99. BRO Lr Of the two terms listed below which one refers to reflection of radio signals back to earth by a satellite la 2 Passive Which term refers to reception and retransmission 1 Active 2 Passive 9 Which of the following terms refers to transmissions received from a satellite Uplink Downlink Modelink Backlink H CO BRO Fe 22205 links are only slightly affected by what phenomena associated with hf propagation difficulties 1 Atmospheric De COSMIC 3 Srezemic 4s 21 6 Trained crews can set up what type of satellite earth terminals within hours to establish communications in remote areas ta 5 2 Defensive 3 Mobile 4 Partial Of the following factors which Lr any limit the use of a satellite communications system 1 Orbital parameters and technical characteristics 2 Transmitter power and receiver sensitivity je L and 2 4 None of the above What purpose does CUDIXS NAVMACS serve 1 Provides an extension to terrestrial teletypewriter networks 2 Provides status reporting and management of system assets 3 Provides a communications link between submarines and shore terminals 4 Provides a communications network for transmitting general service message traffic between ships and shore installations How many NCTAMS have primary responsibility for communications via satellite 1 One 2 Two 3 Three
100. C 3 V 1 Similar to AN WSC 3 SWR meter added Chassis RT 1107 V 1 WSC 3 V wired for FM Vinson Secure Voice Link 11 and SAS C 9351 WSC 3 but without FM Vinson S V Link 11 or SAS modules SAS Single Audio System AN WSC 3 V 2 e RT 1107 V 2 WSC 3 V e C 9351 WSC 3 AN WSC 3 V 3 e RT 1107 V 3 WSC 3 V e C 9351 WSC 3 AN WSC 3 V 4 AN WSC 3 V 5 AN WSC 3 V 6 e RT 1107 V 6 WSC 3 V e C 9351 WSC 3 AN WSC 3 V 7 e RT 1107 V 7 WSC X V e C 9351 WSC 3 AN WSC 3 V 8 e RT 1107 V 8 WSC 3 V e C 9351 WSC 3 AN WSC 3 V 9 RT 1107 V 9 WSC 3 V C 9351 WSC 3 AN WSC 3 V 10 e RT 1107 V 10 WSC 3 V C 9351 WSC 3 AN WSC 3 V 11 e RT 1107 V 11 WSC 3 V e C 9351 WSC 3 AN WSC 3 V 12 e RT 1107 V 12 WSC X V e C 9351 WSC 3 AN WSC 3 V 13 e RT 1107 V 13 WSC X V e C 9351 WSC 3 AN WSC 3 V 14 Similar to V 7 but uses a bidirectional MIL STD e RT 1107 V 14 WSC 3 V 1553B bus interfaced to an external controller 3 26 Similar to V 1 with FM Vinson S V and Link 11 modules added Standard Interface Module Similar to V 2 but with SAS module None produced None produced Similar to V 5 FM Vinson S V standard interface and Link 11 modules added Similar to V 6 but with SAS I O module Similar to V 7 with computer compatible serial frequency and mode control USCG Similar to V 3 Modified for 5 kHz channel
101. C2 In FM transmitter the audio Signal shifts the carrier frequency in what network 1 Audio shift 2 Phase shift Se Carrier shure 4 Band shift In a ssb transmitter the carrier is removed to concentrate the power in the sideband s 1 True 2 False Which of the four receiver functions involves extraction of the modulation from the rf signal 1 Detection 2 Reception 3 Reproduction 4 Selection Which of the four receiver characteristics require compromise because of bandpass requirements Selectivity and noise Selectivity and fidelity Noise and fidelity Noise and sensitivity H GO Fe What term is used to describe receiver amplification 1 Fidelity 2 Noise 3 Gain 4 Power The term dBm is based on what standard reference level watt VOLT milliwatt midlrwoLt CO BO Fe p pq Ln KRAON B 1 23 Normal power out 15 100 watts During PMS vou discover that power out has dropped by 3dB What is the new power out 1 97 watts 2 70 watts 3 50 watts 4 3 watts How many radio set controls can be paralleled to one transmitter receiver group 1 One 24 Iwo 3 Three 4 Four To transfer control of switched circuits to another transmitter or receiver switchboard you should use what switch position OLE X Five Sax A WN e Which of the following terms is used for a machine that operates as a single phase transformer 1 Servo Za Sy
102. DAMA nets have been established Voice Transmission The rf terminal installations on mobile platforms determine the manner in which a Secure Voice transmission is made These mobile platforms maybe categorized into two types e The small ship submarine that share a single channel AN WSC 3 V uhf transceiver and cryptographic equipment between NAVMACS or SSIXS and a Secure Voice terminal e Larger ships that have two or more AN WSC 3 V uhf transceivers and cryptographic equipment are installed This installation normally has a transceiver dedicated to Secure Voice Secure Voice use is accomplished by either of two methods In the first method ships access a Secure Voice channel if the channel is not in use The ship contacts another ship directly by using the available channel When coordination of voice communications with shore commands is required the ship contacts the voice controller who in turn tells the recipient s of an incoming voice transmission DIGITAL SUBSCRIBER TERMINAL 2400 BPS AFLOAT VOICE AUTOSE ERF PANTE p po G r LU UTI TT DTI e T O INTER s scc v lal X Remorse b CONVERTER p CONNECTING croup Psk transceiver _ PSK O O 4 l uDoDcrA ON143 V 4 USQ aN wsc3 danywecsant MODEM 4 cv 3333 U amp 143
103. DS 2 ink 11 E Normalized Data wv Link 16 Series Messages Link 16 Messages EN MIL STD 1553B Bus Figure 7 6 The Link 16 Model 5 ACDS system block diagram JOINT TACTICAL INFORMATION DISTRIB ON M JTIDS TERMINAL 38NP0177 Data flow to the Link 16 JTIDS terminal is from the ACDS computer through the C2P computer to the Link 16 computer Link data generated by the ACDS computer is now normalized to be independent of any one particular link system The C2P computer reformats the normalized data into the format necessary for transmission over Link 16 The C2P computer can also format the normalized data for transmission over Link 11 and Link 4A If necessary all three link systems can be in operation at the same time The JTIDS Terminal The JTIDS terminal used in Link 16 is the AN URC 107 V 7 This is an advanced radio system that provides secure jam resistant digital data and voice communication among a large number of users This radio system combines the functions performed by the Link 11 crypto device data terminal set and radio into one cabinet Many other capabilities are also incorporated in the radio These added capabilities include the following Precise participant location and identification Relative navigation Synchronization Secure voice Relay e Built in test Shipboard Terminal The AN URC 107 V 7 JDIDS terminal is
104. DS Block 0 and AEGIS Model 5 is similar to ACDS Block 1 The C2P system installed ASSOCIATED EQUIPMENT MAGNETIC TAPE SUBSYSTEM PRINTER DATA ADVANCE TELEPRINTER COMBAT DIRECTION SYSTEM DATA COMPUTER Se eee eee eee LINK 11 16 CONTROL DATA LINK 4A 16 CONTROL DATA CONTROL i i i i L l I i 1 L AN UYQ 62 V 1 SUBSYSTEM ASSOCIATED EQUIPMENT LINK 11 TERMINAL LINK 16 TERMINAL l LINK 4A CP2 COMPUTER LINK 4A SET pun para TERMINAL I NAVAGATION Mica CONTROLDATAI FORE ART 38NP0181 LINK 11 ICONTROL DATA ICONTROUDAT MMI CONTROL DATA DATA TERMINAL SET Pa Re n Figure 7 10 The C2P system block diagram for ACDS Block 0 platforms on an ACDS Block 0 platform is very similar to the system that is installed on AEGIS Model 4 platform Figure 7 10 illustrates the system block diagram of C2P for ACDS Block 0 platforms Link messages generated in the ACDS computer are sent to the C2P computer where they are formatted for transmission on the proper link Link 4A Link 11 or Link 16 Depending on the mode of operation and Operator entered parameters some messages may be sent over two or more data links For example it is not uncommo
105. ESTION NOT Abd ITEMS IN IHE 1151 ARE USED 0 14 removable assembly that stores cryptovariables Ps 0 ES Ed CO wW Generates a 75 MHz intermediate frequency for internal communications D w NE U Q W D 29 Provides the interface with the antenna Performs digital to analog and analog to drgaital conversion of voice signals A CO He O QU The Command and Control C2P system controls and manages the interface of which of the following data links Link 4A only LhiznkeLL only Laonk l6 only All tactical data links Ww NF Messages received by the C2P over the Link 11 net cannot be retransmitted over the Link 16 net 1 True 2 False A local area network LAN performs which of the following functions 2 1 Enables users to share data 2 Enables users to share peripheral devices 3 Allows users to send and receive messages via computer 4 All of the above Which of the following items is a node in a LAN system Twisted pair cable Communications media Fiber optic cable Large capacity hard drive Hm CO PM rmm Qu ou O22 T Twisted pair cable used in a 0 209 LAN has which of the following advantages 1 High data transmission speeds 2 Low costs and easy to install 3 Shielded from electrical interference 4 Secure data transmission 629 In designing a LAN system that requires the transmission of digital data audio and vid
106. EXSWITCH In the FULL DUPLEX position this switch enables full duplex operation of the data converter and the computer I O adapter It also enables loop back processing of the transmit sidetone data for input to the computer In the HALF DUPLEX position the DTS operates in the half duplex mode and the transmit sidetone is disabled from being processed STATUS RECEIVE SUMMARY LAMP ora nr SRY e O OO amp S S O CONFIGURATION c FAULT INTERNAL DOPPLER FULL O MONITOR 100 KHZ CORR ON DUPLEX 7 IN 6 U R O RESET EXTERNAL CORR OFF HALF L or Y SIDEBAND SELECT O _ N USB 1200 2400 N DL TADIL LSB 22 FAST FCONT i nd nsum ll FAST ss FPO gt D ise 0 SELF OFF TEST S8NPO158 Figure 4 15 The AN USQ 59 mode control panel and input to the computer Link 11 uses the half duplex mode SIDEBAND SELECT SWITCH When the SIDEBAND SELECT switch is placed in the LSB or USB position the DTS processes only the lower sideband or upper sideband of the received signal When the switch is in the DIV position the DTS combines both the upper sideband and the lower sideband signals to create frequency diversity data for input to the computer When the switch is in the AUTO position the DTS selects the signal with the best receive quality for processing The AUTO position
107. FF position that module is skipped even if it contains a valid address When enabled by the DTS the address selector module sends the address entered in the thumb wheels to the DTS and the call indicator light The call indicator will remain lit until the DTS sequences to the next address module CDS INPUT OUTPUT CONTROL The data terminal set controls the exchange of data with the CDS computer As described earlier input output communications protocol is accomplished through the use of external interrupts The prepare to transmit data interrupt the prepare to receive data interrupt and the end of receive data interrupt are used to control most of the DTS to the computer interface CDS Computer Input Receive Data Cycle The input data cycle is initiated by the DTS When the DTS recognizes the second frame of the start code it sets the prepare to receive data interrupt on the input data lines and sets the external interrupt line The computer acknowledges the receipt of the interrupt by sending an input data acknowledge IDA to the DTS 4 17 Address selector module Typical 20 places is bo N RA OION I y t QV J gt gt Ss SS D 3 d n ANS C Ry 9o Oe gt ZR 3 i i OS Figure 4 17 The Address Control Indicator C9062 U Upon receipt of the first message frame the DTS demodulates the 2
108. Figure 7 5 illustrates the concept of a stacked net used for air control Net 1 is a group of aircraft controlled by the ship while Net 3 is a group of aircraft controlled by an E 2 If the E 2 requires additional aircraft the ship can direct the aircraft under its control to the E 2 As the aircraft approaches the E 2 the pilot can switch to Net 3 and immediately become an active participant in the new net Even though the operator has several nets available to monitor or use a single terminal can transmit or receive on only one of them for each time slot Stacked nets are possible because the frequency hopping pattern is different for each net Examples of stacked nets are voice nets and control nets ee A AU FI A SUR NET3 A N LN SS san aeu Figure 7 5 Stacked nets using Link 16 Link 16 Data Exchange Link 16 transmits data serially using 70 bit data words During the transmit time slot either three six or 12 data words can be transmitted The number of words transmitted depends on whether the standard packed 2 or packed 4 data packing structure is used The number of words that composes Link 16 message is variable but is normally 1 2 or 3 words There are three types of messages fixed format free text and variable format The fixed format messages are called J series messages and are used to exchange tactical information Free text messages ar
109. HF F O will also have the capability of transmitting and receiving ehf telemetry and command data User interfaces for UHF F O are identical to those of the current FLTSATCOM and LEASAT constella tion The uhf portion of the UHF F O system is compatible with all existing Navy uhf terminals except those using frequency hopping techniques Channel Allocations The F O satellite channels are allocated and grouped as follows e Group I has a single 25 kHz bandwidth channel with a variable satellite translation frequency and a jam resistant shf up link Group II has nine 25 kHz bandwidth channels with a satellite translation frequency of 41 MHz e Group III has eight 25 kHz bandwidth channels with a satellite translation frequency of 33 6 MHz Group IV has eight 5 kHz bandwidth channels with a satellite translation frequency of 73 1 MHz Group V has thirteen 5 kHz bandwidth channels with a satellite translation frequency of 53 6 MHz MILSTAR MILSTAR is a new generation Satellite Communications system being developed by the Navy Army and Air Force for two primary purposes First it will provide a survivable NORTH 3 PANEL NIH CELL BATTERY PACK 4 68 BUS M ELECTRONICS hf SHELF N PROPULSION MODULE FORWARD S BAND use SOUTH COMMUNICATIONS ELECTRONICS SHELF SOUTH 3 PANEL SOLAR NP X 2 ETV30057
110. HOCK A ___ MOUNT gt A 2227 KD 21 WW A A yy Au SM lt EF _ ANTENNA Cx 22 A SOCKET Pa A fw Vb s ZA M e 7 uU al lo xv A DERRY A 27 SJ BATTERY PREK SA erp 24 J M ETV30036 Figure 2 24 Transceiver AN PRC 104 transmission of tty or other data It can be used in the man pack configuration or can be configured for vehicular or fixed station operation Unlike older radio sets there are no front panel meters or indicator lights on the AN PRC 104 AII functions are monitored by the radio itself and communicated through the handset in the form of audio tones This is extremely useful during tac tical black out operations Newer versions of the 2 26 AN PRC 104 have modified the R T section of the radio but the above information still applies AN PRC 113 The AN PRC I13 is a two band vhf uhf amplitude modulated transmitter receiver which operates at 116 0 through 149 975 MHz in the vhf band and 225 0 through 399 975 Mhz in the uhf band When interfaced with TSEC KY 57 crypto equipment this radio can operate in AM voice or AM secure voice AN PRC 117 The AN PRC 117 Full Band Frequency Hopping VHF FM Manpack Transceiver with integrated COMSEC shown in figure 2 25 operates in the 30 to E aee 11 6 IN 295 11 3 LB
111. ITCH The TRANSMIT RESET switch is a momentary contact pushbutton switch When depressed this switch causes any transmission in progress to be terminated The DTS stops the transmission by inhibiting the generation of the output data request causing a stop code to be transmitted The DTS also resets the address control address sequence logic TRANSMIT INITIATE SWITCH The TRANSMIT INITIATE switch is a momentary contact pushbutton switch that causes the DTS to initiate data transmission when the DATA RATE switch is in the TADIL A position The TRANSMIT INITIATE switch must be depressed to initiate all DTS transmissions except when the DTS is configured as a picket and is in the roll call mode When the net is in the roll call mode only the net control station is required to initiate transmission by depressing the TRANSMIT INITIATE switch MISS CALL INDICATOR The MISS CALL indicator is lighted when the net control station has detected no response from a picket station after two successive interrogations Once lit it will remain lit until a picket responds or the TRANSMIT RESET switch is depressed ADDRESS COMPUTER CONTROL SWITCH The ADDRESS COMPUTER CONTROL switch determines the source of the address used by the DTS When the switch is in the CONTROL position addresses are obtained from the address control unit In the COMPUTER position addresses are obtained from the CDS computer provided the computer is configured
112. N configurations e The system can notify the user of the transmit operating mode selected both visually and with audio indications e The system can notify the user by visual indica tion if the voice station equipment is not con nected to a crypto or plain subsystem e The system can notify the user of any incoming secure CIPHER signals by both visual and audio indications except for the FLTSATCOM secure voice configuration e The user can select a voice channel and have 1t indicated visually In addition to these capabilities the ASAS version has the following features e processor controlled programmable voice TRANSMITTER TRANSMITTER amp ANTENN F3 REC NER RECEIVER gt TRANSFER RADIO SYSTEM SWITCHBOARDS EQUIPMENT 4 Figure 2 13 Single Audio System SAS 2 14 A voice switch self test and fault location read out built in test An audio indication to the user when the voice switch built in test BIT detects a trunk line short A technical control monitor phone incorpo rated into the voice switch which can access all voice channels SYSTEMS EQUIPMENT AND LOCATION The following paragraphs provide a brief description of the major equipment included in a typical SAS installation Figure 2 13 illustrates the audio path of the system and the order in which we will discuss the equipment User Station Equipment User station equipment is loc
113. N interconnects a relatively small number of personal computers PCs data storage devices printers and other peripherals These nodes and links usually cover a relatively small geographical area such as an office or a department Through common usage the term local area network can also refer to much larger systems such as the SNAP III system on a ship which could have literally hundreds of terminals and miles of cables For our purposes we will be using a small system in our discussion of LANs Any device connected to the network can send and receive data on the network A majority of data exchanged over a network is text and graphics which is assembled as structured data that can be manipulated by computers Unstructured data such as pictures and facsimile messages can be stored and retrieved efficiently but cannot be manipulated easily by the computer After completing this chapter you should be able to Describe the major components of a LAN State the types of cable used in a LAN State the function of the network interface card Describe the function of the various network servers required by a LAN Describe the function of the central mass storage area of a LAN Describe the Open System Interconnection OSI Reference Model used in the design and implementation of a LAN Describe the advantages and disadvantages of the different LAN topologies Describe the hardware systems used in LANS
114. NONRESIDENT TRAINING COURSE July 1997 Electronics Technician Volume 3 Communications Systems NAVEDTRA 14088 DISTRIBUTION STATEMENT A Approved for public release distribution is unlimited Although the words he him and his are used sparingly in this course to enhance communication they not intended to be gender driven or to affront or discriminate against anyone DISTRIBUTION STATEMENT A Approved for public release distribution is unlimited By enrolling in this self study course you have demonstrated a desire to improve yourself and the Navy Remember however this self study course is only one part of the total Navy training program Practical experience schools selected reading and your desire to succeed are also necessary to successfully round out a fully meaningful training program COURSE OVERVIEW After completing this course you should be able to recall the basic principle and the basic equipment used for rf communications recognize frequency bands assigned to the Navy microwave communications the single audio system SAS and the basics of the Navy tactical data system Analyze the operation of the Navy s teletypewriter and facsimile system the basics of the TEMPEST program and the basic portable and pack radio equipment used by the Navy Identify basic satellite communications fundamentals fleet SATCOM subsystem shore terminals and basic SATCOM equi
115. NP0173 Figure 7 2 The CP 2205 P V USQ 125 data terminal block diagram terminal has the following three major components a processor board a CDS interface board and the power supply Figure 7 2 is a block diagram of the CP 2205 P V USQ 125 data terminal The processor board performs modulation demodulation and error detection and correction and provides the interface with the radio set The CDS interface board provides the interface with the CDS computer The CP 2205 P V USQ 125 data terminal performs many of the same functions as previous Link 11 data terminal sets These functions include the following Data conversion Data error detection and correction Control code generation and detection Synchronization Encryption device data transfer Computer and radio control signals for two way Link 11 data transfers In addition the CP 2205 P V USQ 125 data terminal provides the following new features Both multi tone and single tone waveform operations Enhanced Link Quality Analysis ELQA Maximum useable frequency MUF option Multi Frequency Link 7 2 On line and Off line System Test Options Multi Tone Waveform Link Multi tone link operations are basically the same as in the previous Link 11 data terminal sets and called conventional Link 11 waveforms The data terminal generates the 605 Hz Doppler tone and 15 data tones The frequencies of the data
116. Naval Com munications Processing and Routing System NAVCOMPARS for general service message traffic and STREAMLINER for special intelligence message traffic Fleet weather data from Naval Oceanographic Command Centers is also transmitted on nonprocessor controlled channels Rf Transmission The FLTSATCOM satellites have two rf channels allocated for Fleet Satellite Broadcast message traffic The primary channel is configured for an shf uplink to the satellite and for translation within the satellite for transmission as uhf in the downlink The second rf channel is designed for backup use only Since two channels are available and several different modulation techniques are used for the uplink there are seven different modes in which the rf link can be transmitted In modes 1 through 6 the shf transmissions are made by the Satellite Communications Terminal AN FSC 79 Mode 7 operates the rf uplink and downlink at ultra high frequencies and uses the uhf transceiver AN WSC 5 V Reception Subscribers receive the uhf downlink signal through the AN SSR 1 receiver system which demodulates and demultiplexes the signal The demuxed signal is decrypted and read into the 4 jseopeo1g IWS 39pq C c ANSIA U31N325 2351 ONIHOLIMS SM VdWOOAVN 1N3Ndino3 i OuvWoLnv SIHdWYDOLdAND L i ALIMOHLNY QNVIWOO 31maivs QNVWWOO 5150 W31SAS NOIIVWXOJNI 3ONVTIIBANTS
117. ONTROL FLEET CONTROL STATUS THE USAF SATELLITE OPERATIONS CINC REPORTING CENTER IS NOT USED CONTRACTOR CHANNEL status REPORTING me ol NAVAL COMPUTER AND FACILITIES AT APPROPRIATE LOCATIONS ARE USED INSTEAD MONITORING AIRCRAFT CHANNEL SIRPFACE SHIPS as taf P S9 7 Wt 915 CHANNEL STATUS REPORTING uis is ad hon NAVAL TELECOMMUNICATIONS DNMAT INFORMATION AREA MASTER STATION OPERATIONAL CONTROL CENTERS H i 5 HEN ETV30053 Figure 3 15 Control Subsystem functional diagram 3 19 2 _________ _ 1509 909 609 309 609 909 1509 1809 SER d ys 7 b a O dr 4 A U 1 7 LASS _ AT NG LI NS t mn RN T0 N o l _ _ _ EE CEL C _ _ 7 SS PP STU SS SS SSS SSS SRS SS SN SS SPSS SENSES SS da EE __ ___ _ _ _ __ _ gis NS lt 2 A 2 9 bs S AER ee LY 4 oo SA S a al A z n Y Y J ww Some TATE a Taf e ee USING GROUND TERMINAL SATELLITE COVERAGE WHEN ANTENNA ELEVATION ANGLE M ay X N 44 Lu ie 1 3i a 3 20
118. R R 1051 URR COMMUNICATION PATCH PANEL 58 1210 UGQ RED FREQUENCY CONVERTER CV 483 URA 17 CLl 211 r EQUIPMENT COMMUNICATION PATCH PANEL SB 1203 UG BLACK ETV30031 Figure 2 19 RFCS receive system 2 22 The comparator section of the convertor compares the signals received in the diversity mode and allows only the stronger signal to be passed on to the communication patch panel Communication Patch Panel The communication patch panel performs the same function on the receive side as it does on the transmit side Crypto Equipment The crypto equipment decodes the received signal so it can be printed out in its original form Teletype The tty equipment converts the dc pulses from the patch panel to a printed copy of the original message The tty shown is a page printer only and does not have transmit capability AFTS SYSTEM Figure 2 20 is a block diagram of a half duplex uhf system Half duplex communication can be in either direction but cannot happen at the same time The term half duplex is qualified by adding send only receive only or send or receive AFTS Transmit Dc signals from the tty are sent to the com munications patch panel where they are fed to the tone terminal set The tone terminal set converts the dc signals into audio tone shift signals The audio tone shift signals are patched to the
119. RE The most important job of a network operating system NOS is to provide file service for the attached computers This allows information retrieval and usage and the storage of data in a shared environment A NOS manages the other resources shared by the network and provides the following functions Directory structure for shared hard disk storage devices File service for sharing and using data Interface to the network for application software programs The means by which the network manager manages the network and its users Network security and data protection Communications with other networks The types of network operating systems include full featured low cost and zero slot operating systems Full Featured Network Operating Systems Most full featured network operating systems allow for high performance flexibility and excellent security measures They require a LAN administrator They require network interface cards Also they can be quite costly Examples of a full featured NOS are EtherNet Novell s NetWare 3Com s 3 Share IBM Token Ring Network and Banyan s Vines Low Cost Network Operating Systems Most low cost network operating systems differ from full featured systems only in the maximum number of users accommodated on the network and the number of security levels incorporated into the Operating system In general they are much lower in cost and are easier to install and use E
120. S AND m _ MULTICOUPLERS E AN SRA 17 OR AN SRA 49 AN SRR 19A OR R 2368A URR then be patched to a teletype printer for plain text printing or to a reperforator where a paper tape will be punched and stored for later printing HIGH FREQUENCY COMMUNICATIONS The high frequency hf band is shared by many domestic and foreign users Portions scattered throughout the band are assigned to the military The Navy s communications requirements have grown rapidly severely taxing its portion of the spectrum satellite communications has relieved some of this congestion and for some types of service has replaced hf for long distance communications pushing hf into a back up role However even with the use of satellite communications hf will continue to be in high demand for sometime We will cover satellite communications in chapter 3 Naval communications within the hf band are grouped into four general types point to point ship to shore ground to air and fleet broadcast but the fleet broadcast are normally operated two way Point to Point Point to point systems provide communications over long distance trunks or via links between fixed terminals A trunk is normally a message circuit between two points using cable fiber or telephone circuits A link is a transmitter receiver system connecting two locations The two locations normally use directional high gain antennas that increase the effective radiated
121. S signals the CDS computer when it has input data or when it wants output data through the use of external interrupts These interrupts include the prepare to transmit prepare to receive and end of receive interrupts DTS CONTROLS AND INDICATORS Many parameters that affect the operation of the DTS are under the operator s control whether the station is operating as a picket or as the net control station Both the operator and the technician must be familiar with the various controls and indicators associated with the DTS The AN USQ 59 uses several control panels that are usually mounted next to the operator s display console These panels enable the operator and the technician to control and monitor the net operation The control panels include a Mode Control panel a TADIL A Control panel and an Address Selection Indicator panel Although the AN USQ 59 control panels are used here to show the controls and indicators of a Link 11 DTS other data terminal sets have similar controls The functions controlled by the AN USQ 59 control panels are software controlled on newer data terminal sets On these data terminal sets the entries an made via the computer control console or the display console DTS Mode Control Panel The DTS mode control panel controls and indicators are shown figure 4 15 The following is a summary of how the controls affect the operation of the link and what the indicators mean TRANSMIT MODE INDICATOR
122. Secure voice capabilities Transmission Protocols Since Link 16 exchanges much of the same data that is used in both Link 11 and Link 4A a brief comparison of the architectures the capacities and the data rates of the three systems is useful During normal operation Link 11 operates using the protocols of the Roll Call mode In this mode each participating unit is polled by the NCS to transmit data On completion of data transmission the unit returns to the receive mode and the next unit is polled until all units have been polled This cycle is continuously repeated Link 11 messages are called M series messages Link 4A uses the time division multiplexing principle with a command and response protocol to enable the operator to control multiple aircraft independently on the same frequency Link 4A messages sent to the controlled aircraft are referred to as V series messages and messages received from the controlled aircraft are called R series messages Link 16 uses the Time Division Multiple Access TDMA principle of data communications Using this architecture with time interlacing provides the system with multiple and apparently simultaneous communications nets Instead of assigning each unit a PU number Link 16 assigns each unit a JTIDS Unit number or JU The JU identifies the units and determines a preassigned set of time slots that designate when the unit transmits and receives data Each time slot 1s 1 128 of a second o
123. T rating It also provides both general and specific information on electronic tag out procedures man aloft procedures hazardous materials 1 solvents batteries and vacuum tubes and radiation hazards Volume 2 Administration discusses COSAL updates 3 M documentation supply paperwork and other associated administrative topics Volume 3 Communications Systems provides a basic introduction to shipboard and shore based communication systems Systems covered include man pac radios 1 PRC 104 PSC 3 in the hf vhf uhf SATCOM and shf ranges Also provided is an introduction to the Communications Link Interoperability System CLIPS Volume 4 Radar Systems is a basic introduction to air search surface search ground controlled approach and carrier controlled approach radar systems Volume 5 Navigation Systems is a basic introduction to navigation systems such as OMEGA SATNAV TACAN and man pac systems Volume 6 Digital Data Systems is a basic introduction to digital data systems and includes discussions about SNAP II laptop computers and desktop computers Volume 7 Antennas and Wave Propagation is an introduction to wave propagation as it pertains to Electronics Technicians and shipboard and shore based antennas Volume 8 Support Systems discusses system interfaces troubleshooting sub systems dry air cooling and power systems Volume 9 Electro Optics 1s an introduction to night vision equipment lasers thermal 1
124. TER RECEIVER a i aC U WU uy ao vll p c 8 ELECTRICAL 0 J MARK AND SPACE IMPLILSES SIGNALS M 4 RECEIVER Oe Figure 2 16 Basic tone modulated AFTS system 2 18 SIMPLEX RFCS TELETYPE SYSTEM A simplex communications circuit consists of a single channel which may have two or more stations communicating over it However they cannot communicate at the same time The stations have to alternate using the channel RFCS teletype systems are used in the If to hf band for long range communications To reduce fading and interference the Navy uses two methods of diversity reception called space diversity and frequency diversity In space diversity reception the V transmitted signal is received by two or more antennas spaced at distances greater than one wavelength Because of the spacing requirements space diversity 15 normally limited to shore stations In frequency diversity two or more signals are transmitted on differing frequencies but carry the same intelligence Another type of frequency diversity is called af diversity or tone diversity and is used with multichannel broadcasts A simplified block of a simplex RFCS system 1s shown inj figure 2 17 Y D C MULTICOUPLER POWER MULTICOUPLER I ITI DI V Lou d ERG CMS Pere see x i
125. The PU History mode display updates one line of data immediately after the specified PU has completed its transmission The information displayed by the Net Display mode is described in the following paragraphs PU The PU number The first number listed is the NCS which has a default number of 77 or the address entered in the NCS field The rest of the PUs are listed in numerical order 0 12 33 0 CVC wi r REL VAR 605 DATA PHAS M 20 4 1 1 6 N a A UNUN N 1 HA UAHA oo000000000000 O 0000 WNW Ww PU 0 RC FAST SIDEBAND USB LSB DIV SIG FRAME PU PWR SWR CNT THRU CF BER 21 37 gt 24 14 100 0 0 21 6 gt 23 16 100 0 0 21 6 gt 22 16 100 0 0 21 6 gt 23 22 100 0 0 21 6 gt 24 14 100 0 0 21 6 gt 22 14 100 0 0 21 6 gt 22 14 100 0 0 21 6 21 14 100 0 0 21 6 gt 23 14 100 0 0 21 6 gt 28 14 100 0 0 21 6 gt 24 20 100 0 0 21 6 gt 25 14 100 0 0 21 6 gt 23 14 100 0 0 21 6 gt 22 16 100 0 0 21 6 gt 22 18 100 0 0 21 6 21 14 100 0 0 21 6 21 18 100 0 0 21 6 gt 23 14 100 0 0 21 441 17 14 100 0 0 REC DATA 36 NCT 3 1 Figure 5 11 The LMS 11 Net Display in PU History Mode SIG PWR The total signal strength of the 16 tones measured in dBm A value of 51 indicates that no signal was received SNR
126. The elf system is a one way communications system from CONUS to at sea submarines The large size of elf transmitters and antennas makes transmission from submarines impractical The principal use of the very low frequency communications system is to provide fleet broadcasts to the submarine fleet and associated ships and activities thorughout the world Additional uses are in long range navigation and time and frequency broadcasts Vif Transmit Vif transmission is normally considered a broadcast that 1s a one way transmission with no reply required The extent and location of the area to be covered determine the transmitter location and power out For worldwide coverage the Navy has installed seven transmitters whose power out ranges from 0 25 to 2 0 megawatts These transmitters such as the AN FRT 87 can operate in either the interrupted continuous wave icw or frequency shift keying fsk mode A typical radio transmitting station is shown in figure 2 2 Receive The vlf receive system receives fsk and radio transmissions and then reproduces the intelligence that was broadcast Receivers used for vlf communications are the AN BRR 3 AN FRR 21 AN WRR 3 and TRANSMITTER BUILDING EXCITER FREQUENCY GENERATOR amp FSK ICW PRE IPA AMPLIFIER SIGNAL INPUT VIA LANDLINES OR MICROWAVE LINK HELIX HOUSE HELIX COMPONENTS AMPLIFIER
127. This number serves as the initial basis for incoming message screening Screened message traffic is sent to the TACINTEL peripheral equipment printer or the interfacing systems The remaining message traffic is discarded without release Future TACINTEL The TACINTEL II program will upgrade the existing TACINTEL and incorporate state of the art hardware and software It will be a computer based message communications system enabling automatic receipt and transmission of Special Intelligence communications for both ashore and afloat users During the transition it will be compatible with the present TACINTEL TELETYPEWRITER SUBSYSTEM The Teletypewriter Subsystem expands existing teletypewriter communications networks by using satellites as relay stations The Navy continues to have numerous uses for the 75 bps tty These include dedicated full time terminations for beyond line of sight tactical and report back circuits and as backup connectivity for networks such as CUDIXS NAVMACS and TACINTEL A non DAMA configured teletypewriter subsystem is shown in figure 3 9 TRANSCEIVER PSK BASEBAND CRYPTO AN WSC 5 V OM 43A USC PATCH TSEC KW 7 EXISTING ETV30047 Figure 3 9 Teletypewriter subsystem non DAMA TADIXS OTCIXS TADIXS supports the exchange of Over the Horizon Targeting OTH T information between shore and fleet based computer systems that support Navy cruise m
128. Tracks out of gridlock Failure to maintain gridlock may be the result of inaccurate positioning data from a ship s sensor from the Ship s Inertial Navigation Systems SINS or from the ship s gyro Failure to maintain gridlock may also be the result of an inaccurate operator entry The SGS computer performs continuous automatic gridlock calculations In the event of an SGS computer failure the flow of Link 11 data to the CDS computer is interrupted To restore Link 11 data 4 3 flow all SGS installations have switches installed that allow the technician to bypass the SGS computer until the fault is corrected Link 11 Security Device A standard model security device such as the TSEC KG 40 commonly referred to as the KG 40 is used with the Link 11 system When the DTS is transmitting data the KG 40 receives parallel data from the CDS computer encrypts the data and sends it to the DTS When the participating unit PU 15 receiving data encrypted data is received from the DTS decrypted and sent to the CDS computer Because of the specialized training and security requirements of cryptographic equipment we will not cover the internal operation and controls of the security device Data Terminal Set DTS The data terminal set DTS is the heart of the Link 11 system The DTS is the system modulator demodulator MODEM the CDS computer sends 24 bits of data to the DTS via the SGS computer and the encryption devic
129. V liquid crystal light valve LED indicator light emitting diode indicator LINK 4A The tactical digital data link for controller to controlled aircraft communications LINK 11 The tactical digital data link for communications among a multiple number of units LINK 16 The tactical digital data link for communications among a multiple number of units This link is a secure jam resistant nodeless high capacity link that uses the JTIDS terminal LSB Lower Side Band LSD large screen display LVPS low voltage power supply MDA Monochrome Display Adapter M SERIES MESSAGES Link 11 messages NCS Net Control Station NCT Net Cycle Time NICP Network Interface Control Program 1 2 N SERIES MESSAGES The normalized messages exchanged between the C2P computer and the ADCS computer NTDS naval tactical data system ODR output data request OJT on the job training OSC operations summary console PA SG pulse amplifier symbol generator PC personal computer PEFT peripheral equipment functional test PIO peripheral I O PIXEL picture element PMS planned maintenance system programmed operational functional appraisal PPI plan position indicator PPLI precise participant location and identification PPU projection plotting unit PROM programmable read only memory PU participating unit RAC radar azi
130. a faster rate the layered architecture of the OSI model will allow you to make this replacement to the physical layer without changing the other layers LAN TOPOLOGIES The physical arrangement of the components of a LAN is called its configuration or topology The three major types of configurations or topologies of a LAN are the linear bus the star and the ring You can also create hybrid topologies by combining features of these configurations For example several bus networks can be joined together to form a ring of buses Each topology requires the components of a LAN to be connected in a different arrangement These components are also referred to as nodes A node 15 any point on a network where data can be sent transmitted or received a workstation a server and so on LINEAR BUS NETWORK The linear bus topology is like a data highway That is all components or nodes are connected to the same cable and the far ends of this cable never meet as shown in figure 8 2 Linear bus LANs best suited to applications involving relatively low usage of the bus coupled with the need to pass relatively short messages from one node to another In many such networks the workstations check whether a message is coming down the cable before sending their messages Since all nodes share the bus all messages must pass through the other workstations on the way to their destinations Each node checks the address attached to the
131. al from the antenna and filters out any unwanted signals so only the proper band of frequencies are passed on to the receiver Radio Receiver The receiver translates the rf signal to an audio signal CONVERTER COMPARATOR Receiver Transfer Switchboard The switchboard 18 used to connect the receiver to any one of the convertors in the convertor group Convertor Comparator Group The convertor comparator group is used with receivers in either space diversity or frequency diversity operation to convert the frequency shift af signal from the receiver into dc pulses that open and close the dc loop according to the mark and space characters received When the system is not using diversity operation each convertor can be used with a separate receiver Petey ESSI LL COPING JACKS IC GROUP AN SRA 17 2 FROM ANTENNA OR P ETIU uf ln alike uf P P ANTENNA COUPLER re x ec T Ba NS O RI SD RI RUE le D KO KO O O K9 O O 909090900094 ____ e j L m a ANTENNA ASSEMBLY AN SRA 12 J 55555 gt _ NY _ DEDS 4E 1 m M lt n 2 gt E i 2U A s L gt J OM o A RADIO RECEIVE
132. alies corrosion and even the time of day can affect the quality of Link 11 communications The Link 11 technician has many tools to enable him to pinpoint problems However oftentimes the technician may misunderstand such tools forget them or not have the knowledge to use them effectively Problems occurring with Link 11 communications are best approached by means of the team concept A typical link team is usually composed of a team leader an ET a FC an OS and an RM The team leader is usually a senior ET and could be the electronics material officer EMO or combat systems maintenance officer After completing this chapter you should be able to e Describe the procedures required for running single station Programmed Operational and Functional Appraisal on the DTS State the circuits verified by the successful completion of single station POFA Describe the procedures for running multi station Link n POFA Describe the components of the LMS 11 Describe the information presented in each of the LMS 11 display modes Recognize common Link n problems as displayed on the LMS 11 LINK 11 MYTHS AND FACTS When a Link 11 problem occurs usually the link troubleshooting team 15 called to the combat direction center Here they can meet with the operator talk to other ships in the link and analyze the displays on the LMS 11 Through these initial steps the team can determine several things such as whet
133. alls from a workstation to low level disk commands 4 Maintaining the list of user privileges and authorizations When designing and building a LAN system all workstations must be from the same manufacturer l True 2 False The OSI reference model is used to define which of the Following Communications standards 1 Interconnection of communications facilities 2 Software 3 Hardware 4 Protocol O33 o4 62995 6250 0237 What layer of the OSI reference model describes the electrical the mechanical and the functional interface of the communications channel Physical layer Data link layer Network layer Transport layer CGO e What layer of the OSI reference model establishes and deletes host to host connections across the network Data link layer Network layer Transport layer Session layer Hm CO BRO Lm As a translator for the network what layer of the OSI reference model provides a common representation for data which can be used between the application processes Network layer Transport layer Session layer Presentation level layer Hm CO DO Fe Which of the following layers of the OSI reference model provides error free transmission of information over the physical medium Physical Data link Network Transpoce H CO e Communications between users on two different machines are established by what layer of the 051 reference model Data link Network
134. ally on side panels that cover this section of the satellite The space craft module contains nearly all other subsystem equipment including sensors attitude and velocity control telemetry tracking and command and electrical power distribution The spacecraft is stabilized on three axes and the body fixed antennas are kept pointing at the sun by a clock drive A FLTSATCOM satellite is shown i Each FLTSATCOM satellite can relay communications on 23 separate uhf channels Of the 23 channels 10 are 25 kHz channels 12 are 5 kHz channels and one is a 500 kHz channel The ten 25 kHz channels are dedicated for Navy use Each 25 kHz uhf down link channel has a separate transmitter Channel one used in primary mode for Fleet Broadcast transmissions incorporates signal processing within the satellite the shf up link signal is translated to uhf N SPACECRAFT MODULE ETV30055 Figure 3 17 FLTSATCOM satellite for down link transmission In addition two of the FLTSATCOM satellites have ehf packages attached FLTSAT Extremely High Frequency Package FEP The Fleet Satellite FLTSAT Extremely High Frequency EHF Package FEP provides ehf communications capability for Army Navy and Air Force ground airborne and ocean going terminals Two FEPs are currently in orbit carried aboard two modified uhf FLTSATs numbers seven and eight FEP operates at ehf frequencies of approximately 20 GHz on the down link and 44 GHz
135. and Washington DC 1977 Technical Manual Volume 1 Digital Data Communications Control Set AN SSW ID U NAVSEA 0967 LP 555 401 Naval Sea Systems Command Washington DC 1973 Technical Manual System Operation and Maintenance Instructions Organization Level Link Monitor System AN TSQ 162 V I SPAWAR EE 190 AB OMI 010 TSQ 162 V 1 Space and Naval Warfare Systems Command Washington DC 1989 Understanding Link 11 Guidebook for Operators Technicians and Net Managers Navy Center for Tactical Systems Interoperability San Diego CA 199 Understanding Link 16 Guidebook for New Users Logicon Inc San Diego CA 1994 User s Manual Link 11 Monitor System Rack mountable LMS IIR Logicon Inc San Diego CA 1990 VLF LF and MF Communications Systems NAVELEX 0101 113 Naval Electronic Systems Command Washington DC 1972 Woodward Jeff The ABC s of Novell NetWare Sybex Inc Alameda CA 1989 3 Address control indicator 4 16 AN SSW 1D E Data Terminal Set 6 5 AN USQ 125 Data Terminal Set 7 1 Antenna couplers 4 4 Antennas 4 5 ARCnet Asynchronous transmission 1 7 C Carrier Aircraft Inertial Navigational System 6 3 Command and Control Processor 7 11 System configuration 7 12 Communications theory amplification 1 10 antennas baud 2 16 dc circuits 2 16 emissions 1 4 frequency diversity 2 19 frequency spectrum 1 2 intermodulation distortion 2 19 line
136. and transmission methods with coaxial cable Baseband coaxial systems transmit digital signals unchanged over a single channel and have several advantages They are inexpensive easy to install and have low maintenance They also allow very high data transmission rates One disadvantage is that they are limited to transmitting digital signals only In contrast broadband coaxial systems require the digital signal to be converted to an analog signal before transmission and then back to digital by modem at the receiving device Broadband systems Support data voice and video signals that may be transmitted of broadband systems are their higher installation costs simultaneously Disadvantages and complex maintenance Fiber Optic Cable Fiber optic cable is the best choice if a secure network is needed Because the cable transmits light the transmissions are immune to interference caused by electrical or electronic devices Also if your network will run through an area of heavy industrial activity or a work place with strong radio frequency interference fiber optic cable is the most appropriate choice Other advantages of the fiber optic cable are that it lasts longer than other types of cable and can carry many more channels Its disadvantages include its high price poor connectivity and low flexibility NETWORK INTERFACE CARD To attach personal computers to the LAN you must connect a network interface card NIC to each PC an
137. anomalies Which of the following options of the CP 2205 P V USQ 125 incorporates a routine to calculate the optimum frequency 1 Enhanced link quality analysis 2 Maximum useable frequency 3 Single tone waveform link 4 Multi frequency link Which of the following options of the CP 2205 P V USQ 125 transmits date through a standard wire line modem 1 Enhanced link quality analysis 2 Maximum useable frequency 3 Single tone waveform link 4 Multi frequency link 5 33 Which of the following options IN ANSWERING QUESTIONS 5 36 THROUGH of the CP 2205 P V USQ 125 5 40 SELECT FROM FIGURE 4A THE SYSTEM incorporates most of the TEST OPTIONS OF THE CP 2205 P V USQ Itunctrons of the LMS 11 LAS DATA TERMINATE SEI DESCRIBED LN THE QUESTION NOT ALL ITEMS IN THE LIST 1 Enhanced link quality ARE USED analysis 2 Maximum useable frequency 5 36 This option is selected when a 3 Single tone waveform link single station POFA is running 4 Multi frequency link without the radio 5 54 Which ort the rollowrng Optrotns 1 Of CPS2205 d 050 925 2 B improves Link 11 operations by Big GE using four frequencies 4 D simultaneously 0591 When BILLS test we ru eie 1 Enhanced link quality computer interface is disabled analysis and a test message is 2 Maximum useable frequency repeatedly sent to the radio 3 Single tone waveform link set 4 Multi frequency link du A 5 35
138. are Systems Command Washington DC 1973 Line of Sight Microwave and Tropospheric Scatter Communication Systems NAVELEX 0101 112 Naval Electronics Systems Command Washington DC 1972 Link 11 Seminar for Operators and Technicians Instructor Notes Link 11 Waterfront Seminar Logicon Inc San Diego CA 1990 1 LMS 11 Troubleshooter s Guide for Link 11 Operations Logicon Inc San Diego CA 1990 Navy UHF Satellite Communications System Description FSCS 200 83 1 Naval Ocean Systems Center San Diego CA 1991 Operating and Service Manual C 12428 USQ 125 Control Unit Cedar Technology Inc Longmont CO 1995 Operation and Maintenance Instructions MX 512PV Link 11 Data Terminal General Atronics Corp Philadelphia PA 1992 Operation and Maintenance Instructions Organizational Level Link 11 Data Terminal Set AN USQ 76 V 3 SPAWAR EE640 DW OMI 0IB EI10 USQ76V3 Space and Naval Warfare Systems Command Washington DC 1990 Operation and Maintenance Manual for the Link Monitor System LMS 4 for Link 4A Logicon Inc San Diego CA 1990 Operator s Manual Digital Message Device Group TM 11 5820 887 10 U S Army Communications Electronics Command Fort Monmouth NJ 1982 Operator s Manual Radio Set AN PSC 3 EEI25 JC OPI 010 U S Army Communications Electronics Command Fort Monmouth NJ 1988 Operator O Level Maintenance Training Course Trainee Guide for the Link Monitor System AN TSQ 162 V 1
139. are is necessary to control the overall operations of the network Careful consideration must be given to the various packages on the market to ensure the operating software is fully compatible with your system topology and needs NETWORK OPERATING SYSTEM BASICS The two basic components of the network Operating system are the network operating system server and the workstation The network server is usually a dedicated computer that runs the operating system software and processes all requests for services The workstation computer runs the application software needed by the workstation user and establishes communications with the network server The network server operating system consists of the following five subsystems the control Kernel the network interfaces the file systems the system extensions and the system services Control Kernel The control kernel is the main subsystem of the network operating software The control kernel coordinates the various processes of the other subsystems Some of the functions performed by the control kernel are as follows Optimizing access to services by users Maintaining status information of many of the processes Error reporting service termination Service initialization and of workstations Network Interfaces The network interfaces provide the low level subnet protocols and basic translation for bridging hardware drivers with the network operating system In s
140. ate dc power supply that provides variable current to the teletypewriters The extra current source normally provides current from the positive side for marks and current from the negative side for spaces There are some advantages to using polar circuits rather than neutral circuits In a polar circuit it is almost impossible to distort a signal by high reactance low line currents or random patching of circuits or equipment A big advantage for the ET is that a com plete loss of current a zero reading on the milliamme ter quickly indicates line or equipment trouble Using neutral signaling this may only indicate that a steady space is being transmitted This condition is known as running open The teletype appears to be running because it 1s decoding the constant spaces that cause the type hammer to continually strike the type box but there is no printing or movement across the page BASIC SYSTEMS When teletypewriters are wire connected looped the exchange of information between them 18 direct When they are not physically joined exchange of information is more complex Dc mark and space intervals cannot be sent through the air The gap between the machines must be bridged using The transmitter carrier transmitters and receivers wave is used to carry the mark and space information A keyer is used to change the dc pulses from the tty into mark and space modulation for the transmitter carrier wave The receiver and a conv
141. ate the performance of the net The 7DATA field will be followed by a number representing the percentage of net cycle time message data is transmitted with no errors The NCT displays the net cycle time in seconds Net cycle time is the time required for one completed polling of the net It can be measured from control stop to control stop from NCS or the operator can specify a PU as the reference for net cycle time The operator can also specify the number of cycles to use to determine net cycle time The operator makes these entries using the summarize parameter in the NET DISPLAY mode Net Display The Net Display mode is activated when the operator presses the NET key on the keyboard The Net Display mode presents the following two separate types of information a Net Summary summarize mode or a PU History history mode In the Net Summary mode the Net Display presents a summary of quantitative information about the performance of up to 21 PUs In the PU History mode the LMS 11 displays data for a selected PU The most recent 21 transmissions of the specified PU will be displayed while in the PU History mode The Net Display mode is only available when the link is in the Roll Call modej Figure 5 10 shows a screen for the Net Display in the Summarize mode and figure 5 11 shows the screen for a PU History mode After the operator enters the Net Display mode there are four operator entries that can affect the
142. ated in operations centers throughout the ship like the bridge combat information center CIC flag plot secondary corm and other stations where exterior voice com munications are required by the ship s mission This equipment consists of telephone sets audio amplifiers loudspeakers headsets recorders audio jackboxes Naval Tactical Data System NTDS consoles and intercom units and local switching devices for added system flexibility Voice Switching Equipment The voice switching equipment is a major component of the SAS It is the interface and primary switch between the user s equipment and all crypto and plain subsystems It is designed for very high interchannel isolation which is a TEMPEST requirement for all equipment that handle both secure and nonsecure signals at the same time The ASAS and MSAS use different switches for this purpose Crypto and Plain Subsystems The various crypto and plain subsystems are located in the main communications spaces Cryptographic devices and other red equipment are located in a secure area within these spaces There are five crypto and plain subsystems used within the SAS NESTOR VINSON PARKHILL FLTSATCOM secure voice and PLAIN ONLY Additional classified information on these subsystems is available on a need to know basis Transmitter and Receiver Transfer Switchboards These equipment are part of the overall exterior communications switching system and are located
143. ating systems In the early days of PC networks very few computers were equipped with a hard disk When the hard disk became affordable manufacturers were asked to develop a system to allow several users to share a single hard drive The earliest disk servers were multiplexers that polled each connected computer for requests to write a file on the hard drive or to retrieve a file from the disk The multiplexer then responded accordingly A major problem with this process was that it did not allow for any type of security data organization or disk management As LAN technology evolved the development of the disk server software in the early 1980s addressed some of these issues The disk server is a software routine that was installed on each computer in the network The disk server software allowed each PC to access the shared hard drive as if it were a local drive In other words the computer thought the drive was installed in the computer but in reality the drive was remotely located on the network The disk server also provided for some information sharing One purpose of a network is to allow multiple users access to the same information One problem encountered with early disk servers occurred when two or more users updated the same file at the same time When the file was saved by both users the updates of one of the users was lost 8 3 A method of preventing this information loss is file locking File locking means that when
144. ats vr M LAM a cM E CS et 2 eee st vC 7 EFL PO TRG SE ait HE at ent wat MES PA SOLAR WING NORTH COMMUNICATIONS ELECTRONICS SHELF RADIATOR SUBNADIR COMMUNICATIONS ELECTRONICS SHELF mearen e BS NS A En c m Fo OS Figure 3 19 UHF Follow On satellite exploded view communications capability to the National Command Authority NCA Second it will provide sufficient communications support for both strategic and tactical missions The primary objective of the MILSTAR program is to develop and deploy an affordable jam resistant SATCOM system that will meet both long haul and local communications needs MILSTAR will use communications terminals that will provide Secure Voice SV Teletype TTY data and facsimile EHF SATCOM MILSTAR terminals will be installed on aircraft in fixed telecommunications centers landbased tactical elements shorebased telecommunications centers surface ships and submarines In the following paragraphs we will look at some of the equipment associated with satellite com munications SATELLITE EQUIPMENT The equipment used in Navy SATCOM sub systems can be divided into two general groups rf terminals and the baseband equipment common to a processor installation The selection of specific equipment is determined by the operating en 3 23 vironment whether installation
145. ay control and operation of naval Dtm satellite communications assets 1 Chief of Naval Operations 2 Satellite Operations Command 3 Naval Space Command 4 Naval Computer and Telecommunications Command 2 44 Of the 23 uhf communications channels each FLTSATCOM satellite has how many one dedicated to Navy use Jur P Zo D Du SEU 4 15 How many FLTSATCOM satellites have ehf packages installed One Two Three BOUT A GO N LEASAT satellites have fewer 25 kHz channels than FLTSATs What ground based system do they use to maintain communications efficiency DAMA MSAS PA VINSON H gt CG BDO ED What is the replacement satellite for GAPFILLER FLTSATCOM and LEASAT 1 UHF F O 2 URO 70 3 SHF F O 4 SRP F O The AN FSC 79 satellite communications terminal transmits on what band EE 22 HE Sw LE 4 Uhf Which of the following is another term used to describe the shf communications band A band S band U band X band H CO Fe The AN WSC 5 V uhf transceiver 15 capable of using differentially encoded phase shift keying and what other type of modulation 1 AM Zw CW Su EM 2H 005 22459 Which or the following radios 2 305 is the primary shipboard los and satellite transceiver 1 AN WSC 3 2 3 AN WSC 5 4 AN WCS 5 The AN WSC 3 transceiver has two rf output levels of these is 30 watts What is the other rf output lev
146. ber 0504 LP 026 7540 Sailor s Creed I am a United States Sailor will support and defend the Constitution of the United States of America and will obey the orders of those appointed over me represent the fighting spirit of the Navy and those who have gone before me to defend freedom and democracy around the world proudly serve my country s Navy combat team with honor courage and commitment am committed to excellence and the fair treatment of all CONTENTS CHAPTER PAGE 1 Fundamentals 1 oen 1 1 Systems Equipment Configurations 2 1 Satellite Communications 3 1 4 The Link 11 System 2 2 a llle _ 41 Link 11 Fault Isolation 5 1 6 L6 I 7 New Technology in Data Communications 7 1 8 Local Area Networks 8 1 APPENDIX LlList of Acronyms References Used To Develop The TRAMAN AITI 1 INDEX ees NONRESIDENT TRAINING COURSE follows the index iii SUMMARY OF THE ELECTRONICS TECHNICIAN TRAINING SERIES This series of training manuals was developed to replace the Electronics Technician 3 amp 2 TRAMAN The nine volumes in the series are based on major topic areas with which the Electronics Technician should be familiar Volume 1 Safety provides an introduction to general safety as it relates to the E
147. ble to nuclear disturbances of the ionosphere Application Meets the communications quirements between HF sites within its minimum skywave one hop distance of about 400 miles and line of site of about 30 miles It is especially useful where conditions prevent the use of line of sight communica tions or if adverse propagation conditions interfere with other transmission methods MULTIPLEXING As we mentioned earlier the rf spectrum has become very congested The maximum number of transmissions taking place in the rf spectrum is being increased through the use of multiplexing Multiplexing refers to the simultaneous transmission of two or more messages over the same medium or channel at the same time Multiplexing may be achieved in various ways but the most common meth ods are time division multiplexing tdm and fre quency division multiplexing fdm Although several types of multiplexing equipment are available in the fleet today the AN UCC 1D is the most common TIME DIVISION MULTIPLEXING Time Division Multiplexing Tdm is a method of combining analog signals for serial transfer The signals are sampled at intervals and interwoven for transmis sion The speed of this multiplexed signal 15 faster than the original individual channel speed by a multiple equal to the number of combined signals For example if 5 signals are multiplexed the data speed of each sig nal must be multiplied by 5 to keep the signals in syn
148. carrying a message and then data is transmitted with the token The token is then passed around the network and every station checks whether the message 15 intended for it The receiving station copies the message from 8 10 NODES AND PC 2 TRANSMIT A MESSAGE CAUSING A COLLISION 1 e uson PC 2 Illi MESSAGE MESSAGE pinaka TIME 08 30 00 000 NODE PC 1 DELAYS RETRANSMITTING ITS MESSAGE 10 1000 OF A SECOND NODE PC 2 DELAYS RETRANSMITTING ITS MESSAGE 20 1000 OF A SECOND NODE 1 RETRANSMITS NODE PC 21S WAITING 1 2 ilii ilii lt lt PC 3 H PC 4 TIME 08 30 00 000 38NP0190 lt Figure 8 6 A bus network using the CSMA CD access method the token but then passes the unchanged token along the network When the transmitting station receives the same token it knows the message has been passed around the network The transmitting station erases the message and puts the empty token back into circulation on the network The amount of information that may be transmitted during possession of the token is limited so that all workstations can share the cable equally PROTOCOLS Network protocols are an important component because they define how networks establish communications between element exchange information and terminate communications Protocols have two major operational functions They establish the circuit for transmis
149. centage of data received during the most recent net cycle 4 The percentage of data that is error free received during the most recent net cycle The net cycle time that is displayed in the LMS 11 status box indicates which of the following time cycles 1 Start code to start code of NCS only 2o SUbOD cLOCOBLEQOL Stop on NES only je SCODEEOT SLOD CO CODDEOl STOD of an operator selected PU only A ODORDLIOL 5160 Lo ccOoDntrolk Stop from either NCS default or an operator selected PU dc s 2 955 4 60 The Net Display mode of the 4 62 LMS 11 is capable of displaying two separate types of information 1 True 2 False In the summarize mode of the net display a summary of 4 63 quantitative information is displayed for a maximum of how many PUS lu LO Die I Ou 2 4 21 The net display mode can only be displayed when Link 11 is operating in which of the following modes 1 Net test 2 Net sync j Roll call 4 Short broadcast The PU field in the header of 4 64 the Net Display screen of the LMS 11 is used to define which ot the following units if any while in the summarize mode 1 NCS 2 Own station PU number 3 The PU whose recurring transmission is used to define a cycle 4 None the PU field is only used during the History mode To change the Net Display screen from the summarize mode to the PU history mode the 4 65 operator would take which of the following acti
150. communications An additional problem is that an aircraft moves much more rapidly than a ship This rapid movement plus additional space limitations requires that all major circuit im provements be made at the ground stations Examples of improvements that can only be made to the ground station are higher powered transmitters lower noise receivers and more efficient antennas Fleet Broadcast As the name implies this service involves broadcast area coverage from shorebased transmitters to ships at sea To overcome propagation problems messages are sent on several frequencies at the same time frequency diversity Space diversity with physically separated receive antennas also helps overcome propagation problems Now let s look at typical shipboard high frequency transmit and receive systems Shipboard HF Transmit The high frequency transmit signal can contain either voice or teletype information shows a typical shipboard high frequency transmit system The same equipment used to receive teletype messages on low frequencies teletype DC Patch Panel SB 1210 UGQ crypto equipment and DC Patch Panel SB 1203 UG are used to send teletype messages on the high frequency system but of course in reverse order An AN UCC 1 V or CV 2460 telegraph terminal converts a dc signal into a tone signal This signal is fed to the SB 988 SRT transmitter transfer switchboard A C1004 transmit keying and control teletype is used to key
151. continuous or both circuits are used to maintain synchronization In the STORED position the DTS uses the time base stored during Net Sync During normal operations this switch should be in the CORRECTED position OPERATE RADIO SILENCE SWITCH The OPERATE RADIO SILENCE switch is a two position toggle switch that allows the DTS to inhibit radio transmissions In the OPERATE position the DTS operates normally When switched to the RADIO SILENCE position the radio keyline and transmit audio circuits are immediately disabled NET CONTROL PICKET SWITCH The NET CONTROL PICKET switch configures the DTS to operate as the net control station or a picket station in roll call mode ERROR CORRECT LABEL SWITCH The ERROR CORRECT LABEL switch determines how the DTS processes detected errors In the CORRECTED position the DTS attempts to correct detected errors If a single bit error is detected the location of the erroneous bit 1s detected and corrected If an even number of bit errors occurs the correction circuitry is inhibited If an odd number of bit errors occurs the correction circuitry attempts to correct the data however if an odd number of multiple bit errors occurs an erroneous correction 15 made When the switch is in the LABEL position the DTS does not attempt to correct detected errors Instead the data word sent to the computer is labeled to indicate that errors were detected in the data word TRANSMIT RESET SW
152. control message The universal test message All of the above H CO LE Which of the following Link 4A test messages causes internal testing of the data terminal set The monitor reply message The monitor control message The universal message All of the above CO DO e Which of the following AN SSW 1 subassemblies provides system timing for Link 4A operations 1 Digital to digital converter 2 Monitor test panel 3 Coordinate data transfer 4 Pulse amplifiers Which of the following pieces of equipment is replacing older Link 11 data terminal sets 1 AN USQ 36 Data Terminal Set 29 3 AN USQ 125 Data Terminal Set 4 Link 16 29 9 2 9 905 Ihe CP 2205 P V USQ 125 processor board performs which ot the rollowing functions 1 Modulation demodulation 2 Error detection and correction 3 Radio set interface 4 All of the above Which of the following CPH2205 gt P AV USO 125 components provides for communications with the CDS computer Processor board Interface board Power supply Modulator rs CO BDO e The CP 2205 P V USQ 125 is capable of data encrytion 1 True 2 False The single tone waveform link Capability or the CP 2205 P USQ 125 provides which of the following functions 15 Interface with a satellite modem 2 Increases UHF transmission range 34 Increases HF transmission range 4 Reduces HF propagation
153. cular unit 4 A computer is not required to participate in the net Which of the following JTIDS security features is designed to prevent jamming 1 Data encryption 2 Waveform encryption L ntroductrom ob Jaztter and noise 4 Frequency hopping Which of the following network participation groups 1s normally excluded from Navy command and control units Weapons coordination ALT OO thet O l Fight to fighter Secure voice GENE JU numbers 00001 through 00177 are normally assigned to which of the following units 1 Link 4A and Link 16 capable UTE S 2 Command and Control units jJ Link lo odpabDle arrcrdft 4 Link 11 and Link 16 capable units Which of the following Link 16 track numbers would designate the same Link 11 track Le 0000 QUT 2e 71177 0200 Groug OFT rl 1 30900 lt ehrouch New Technology in Data Communications throug Jl 8 pages 8 1 through 8 14 continued 0 04 Oc 0685 pea 32 6 chapter 7 Local Area Networks pages chapter track that Nas a reported track quality of 15 indicates the track is within exactly how many feet of the reported position b 2B 2 5 Dacus Bu An Which of the following track identifications has been added for use with the Link 16 system 1 Neutral 2 Hostile 3 Assumed hostile 4 Unknown The identifier Unknown assumed enemy has been
154. currency cannot be assured Therefore you need to be sure that you are studying the latest revision AN PRC 113 Harris RF Communications 31R2 2PRCII3 1 1680 University Avenue Rochester New York NY no date AN PRC 117 Harris RF Communications 31R2 2PRC117 1 1680 University Avenue Rochester New York NY no date Black Uyless D Data Networks Concepts Theory and Practice Prentice Hall Inc Englewood Cliffs NJ 1989 Communications Link Interoperability Planning System CLIPS Systems Integration and Test Division Naval Electronics Systems Command Engineering Activity St Inigoes MD 1988 Data Communication System AN USC 30 NAVSEA 0967 563 9010 Government Telecommunications Division Collins Radio Group Rockwell International Dallas TX 1975 Durr Michael Networking Personal Computers 3d ed Que Corp Carmel IN 1989 Electronics Installation and Maintenance Book Communications Handbook NAVSEA SE000 00 EIM 010 Naval Sea Systems Command Washington DC Sep 1979 Electronics Technician 3 amp 2 NAVEDTRA 10197 Naval Education and Training Program Management Support Activity Pensacola FL 1987 Hancock Bill Designing and Implementing Ethernet Networks QED Information Sciences Inc Wellesley MA 1988 Heath Steve Effective PC Networking Butterworth Heinemann Ltd Oxford England 1993 Instruction Manual Data Terminal Set AN USQ 59 V 2 SPAWAR 0967 LP 563 9020 Space and Naval Warf
155. cy hf band so a large percentage of shipboard transmitters and re ceivers are designed to operate in this band On board your command you may find satellite communica tions has pushed hf into aback up role cations The ultra high frequency uhf band is used exten sively by the Navy for LOS and satellite communica tions Mobile communications radar over 400 MHZ and special operations are some other uses A significant portion of the very high frequency vhf band is assigned to the commercial television in The super high frequency shf band 15 the work dustry Some naval uses of the vhf band are mobile horse of microwave communications LOS communi FREQUENCY HZ 3 4 5 6 7 8 9 10 11 3X10 3X10 3X10 3X10 3X10 3X10 3X10 3X10 3X10 3x10 3x40 3x40 3x10 73x10 3X10 3x10 13x10 93x 107 3x18 22 MICROWAVES X RAYS a VISIBLE RAYS LIGHT COMMUNICATIONS GAMMA ULTRA RAYS RADAR VIOLET INFRARED vF iF SHE 40 140 104 105 409 107 108 109 1010 4g 1072 Figure 1 2 Frequency spectrum 1 3 cations terrestrial and satellite relay links radar and special operations are some other uses Experimental use of the extremely high frequency ehf band is ending The Fleet Satellite FLTSAT Ehf Package FEP is attached to two modified uhf FLTSATs The FEP is currently provid ing ehf communications capability to Army Navy and Air Force ground airbo
156. d attach the network cable to the NIC Each individual workstation must have a network interface card The NIC is nothing more than a circuit board that normally plugs directly into one of the expansion slots inside a PC Sometimes the NIC comes as a separate unit In this case you would plug it into the back of the PC Most NICs have their own built in microprocessor s designed to take care of network communications This relieves the PC s main processor of this responsibility The type of cable used on the network is determined by the type of LAN to be installed NETWORK SERVERS Your understanding the concept of a server is important to understanding how LANs work A server is a combination of hardware and software that is used to manage the shared resources of the network The hardware may be a PC or a computer designed specifically to act as a server A network server is able to control network traffic as well as the sharing of other resources such as application programs disk space data files and printers In either case the computer normally has a hard disk and the software needed to run the network system There are several different types of servers and each has a particular function In newer systems some separate server functions are combined into a central file server The Servers we will look at are the disk server the file server and the print server Disk Server The disk server was the first of the network Oper
157. data rates from 75 to 9600 bps FSK modulation at 75 bps and FM or AM modulation for voice The rf output is 30 watts AM and 100 watts for FM PSK and FSK The AN WSC 3A AN WSC 3A V 2 and V 3 have been modified for use with the DAMA subsystem The AN WSC 3 V 1I5 17 and V 19 manufactured as DAMA capable The transceiver has two control indicators for remote operations The C 9351 WSC 3 shown in figure provides for remote control of the AN WSC 3 as described in the table 3 1 description As we mentioned before the C 9899 WSC 3 provides for remote teletype operation Two built in modems are included with the transceiver Receiver Systems AN SSR 1 and 1A You have probably seen this receiver since it is installed aboard most naval surface vessels It enables ships to receive Fleet Satellite Broadcast The received carrier may contain either FM or PSK modulation the preferred demodulation 15 selected manually with a switch associated with the receiving set The AN SSR 1 can drive high level teletype equipment The AN SSR 1A can drive both high and MAA RY FRIG s ON SELECTED o6 o PRESET 9 19 n X ren 4 ETV3006 1 Figure 3 23 Control Indicator C 9351 WSC 3 Table 3 1 AN WSC 3 Variations AN WSC 3 AM Voice AM Secure Voice FM Voice PSK Data at e RT 1107 WSC 3 75 300 1200 2400 4800 9600 bps FSK Data at 75 C 9351 WSC 3 bps via satellite or LOS selectable AN WS
158. dcast canned test data to all pickets within the net The data terminal set contains a code generator that generates twenty one 30 bit data words Once all the words in the word table have been generated the process automatically starts over and keeps running until stopped by the operator Net Test will test the connectivity between all units and the operation of the DTS Since it is a local test Net Test does not check the interface between the CDS computer and the DTS Net Testis also helpful to the technician for setting the audio input and output levels of the DTS or radio set Roll Call Roll call is the normal mode of operation In this mode the operator on the NCS platform enters ownship s address and an assigned address PU number for each PU in the proper switch position When the link is initiated each PU is polled for data Polling consists of sending a call up message If the PU fails to respond the call up is repeated If the PU still does not respond it is skipped and the next PU is polled When a PU recognizes its own address the PU will transmit its data to all the participants in the link When the NCS recognizes the end of the PU reply it automatically switches to the transmit mode and calls up the next PU address After all the units in the net have been polled the NCS transmits its own data and the process is continuously repeated The roll call mode provides all PUs with continuous near real time exchange of
159. display can operate in broadcast short broadcast and Roll Call modes In Broadcast and Short Broadcast the display is updated after every transmission In Roll Call mode the display is updated after the specified number of net cycles or 200 transmissions whichever occurs first When the net cycles are set to zero the display updates immediately after the designated PU has transmitted The PU display is shown in figure 5 12 The PU display is activated when the operator presses the PU function key on the keyboard The information in the PU display 15 presented in two bar graphs with additional amplifying information just under the bar graphs In the PU display header the operator enters the address of NCS or 77 the address of the unit to be evaluated the sideband to be evaluated USB LSB or DIV and the number of cycles to summarize for the display The following paragraphs describe the information presented in the PU display RELATIVE POWER dB This bar graph displays the relative power in each of the Link 11 tones The relative power is calculated with respect to the average of the data tones The expected values should be 6 dB for the 605 Hz tone tone 5 and 0 dB for the data tones The TADIL A specifications allow for a difference of 1 5 dB between the maximum and minimum power levels of the data tones A noisy signal may cause the power levels of the data tones to deviate considerably from the standard The bar graph
160. duces 50 kW peak envelope power 25 kW average power and covers a frequency range of 30 to 150 kHz Low frequency transmitters are normally used only on shore stations Lf Receive The low frequency receive system receives lf broadcasts and reproduces the intelligence that was transmitted A typical If receive system is shown in figure 2 4 The antennas receive the If signal and send it to the multicoupler and patch panel The multicoupler and patch panel AN SRA 17 and AN SRA 49 allow the operator to select different antennas and connect them to various receivers In the system shown in figure 2 4 the receiver can be either the AN SRR 19A or the R 2368A URR These receivers operate in the frequency ranges of 30 to 300 kHz and 14 kHz to 30 MHZ respectively The receiver audio is fed to the SB 973 SRR receiver transfer switchboard As we explained earlier this allows the received audio to be connected to numerous pieces of equipment Ir figure 2 4 the audio is connected to either an AN URA 17 or CV 2460 convertor comparator which converts the received signal to dc for use by the teletype tty equipment From the convertor the dc signal 15 fed to a dc patch panel SB 1203 UG The signal can then be sent to any crypto equipment attached to the patch panel The crypto equipment decrypts the signal and routes it to the red patch panel SB 1210 UGQ The signal can RECEIVER ANTENNA Y PATCH LOW __ PANEL
161. e The DTS adds six bits of data for error detection and correction These six bits are called hamming bits The 30 bits of data are phase shift modulated into 15 audio tones These 15 data tones and a Doppler correction tone are combined into a composite audio signal which is sent to either the UHF or HF radio for transmission The DTS receives the composite audio signal from the radio and separates the 15 data tones and the Doppler correction tone The 15 data tones are demodulated into 30 data bits The six hamming bits are checked for errors and the 24 data bits are sent to the CDS computer via the encryption device and the SGS computer Link 11 Communications Switchboard The communications switchboard provides for manual switching of the data terminal set and individual HF and UHF radios The communications switchboard provides system flexibility and casualty recovery capabilities A typical switchboard will provide the following interconnections The Link 11 data terminal set to one or more HF radio sets to provide the standard HF Link 11 capability Link 11 data terminal set to one or more radios sets to provide UHF Link 11 capability The same communications switchboard may also be used for connecting a Link 4A data terminal set to one or more UHF radios to provide standard UHF Link 4A TADIL C capability Link 4A is covered in detail later in this book Radios The Link 11 system can operate with eith
162. e 30 bit word is generated by adding the relative phase angles of the USB and the LSB Because of propagation anomalies noise and interference the AUTO mode can be used to select the sideband USB LSB or DIV that yields the most correct data automatically In the AUTO mode the DTS processes a word from each sideband and the diversity combination The decoded words are examined for errors in the following order or priority DIV USB and LSB A search of the three words 1s made to find a data word with no error If one is found it is selected for input to the CDS computer If none is found the RCV DATA ERR indicator is lit and the diversity combination data word is sent to the CDS computer Radio Set Interface The DTS generates the following outputs to the radio set upper sideband composite audio lower sideband composite audio and key line It receives upper sideband composite audio and or lower sideband composite audio UHF radio sets use only the upper sideband signal and the key line signal The key line signal controls the transmit and receive state of the radio set The key line is set to transmit Link 11 data When the key line is cleared the radio set returns to the receive mode 5 LINK 11 FAULT ISOLATION INTRODUCTION A communications network such as the Link 11 system can be very complex when the goal is to maintain high quality communications with all units in the net Distance atmospheric anom
163. e OPERATE mode exactly how many fault sensing sensors can cause the SUMMARY FAULT lamp to light qu X Zy d Due uo 4 27 The LAMP TEST switch on the Mode Control Panel will cause all of which of the following lamps to light 1 Those on the mode control panel only 2 Those on the TADIL A control panel only 3 Those on the address control On Ly 4 Those on the mode control panel the TADIL A control panel and the address Control unit When the FULL DUPLEX HALF DUPLEX switch is in the FULL DUPLEX POSITION the transmit sidetone is processed for input to the computer 1 True 2 False When the SIDEBAND SELECT switch is in the DIV position which sideband signal is processed for input to the computer ie USB only 2c 9B Only 3 The combination of the USB and LSB signals 4 Either the USB or the LSB depending on the signal quality of each sideband During Normal operations the DATA RATE switch on the mode control panel should be in which of the following positions is 2200 Dos 2 2 400 bps 2 DUAL 14200 4 TADIL A 16 gens The SYNC MODE switch on the mode control panel is used in conjunction with which of the following switches on the TADIL A control panel 1 OPERATE RADIO SILENCE switch 2 NET CONTROL PICKET switch 3 TIMING STORED CORRECTED switch 4 ERROR CORRECT LABEL switch When the SYNC MODE switch is placed in the FAST position synchroniza
164. e a problem More than one buffer may indicate a problem but multiple buffers from an UNREC STA can also be caused by interference on the frequency The printout will also indicate the parity status of the words received in error During the POFA since the computer knows the contents of the received data block it performs a parity check on all received words These parity checks are compared with the parity status received from the DTS The printout indicates these parity checks The heading PARITY STATUS OF ERROR WORDS lists the number of error words detected by the DTS and the parity 1 2 or 3 The heading PARITY STATUS OF CORRECT WORDS indicates the computer parity check of words received as correct from the DTS When an error is detected the number of words in error for each of the three parity status conditions are listed here The final part of the printout indicates the remote station reports These reports are sent by other stations as part of the data transferred during the POFA Since a multi station POFA is subject to various types of interference both natural and man made several attempts may be required for you to achieve acceptable results Shifting NCS and repositioning the ships are just two of the actions that could contribute to achieving a successful multi station POFA THE LINK 11 MONITORING SYSTEM LMS 11 The link is down is a statement that can strike fear into even the most seasoned technician As
165. e compatible on both the transmit and receive ends Remote Transmitter Control The remote transmitter control unit is mounted close to the tty keyboard and permits remote control of the transmitter For RFCS operation the operator sets the three position rotary switch to CFS SEND to transmit and CFS REC for receiv ing The TONE S R position is used for AFTS transmit and receive Transmitter Switchboard The SB 863 SRT switchboard is used in this system to connect the remote transmitter control to the transmitter to be used Transmitter The transmitter is used to transmit the RFCS signal It is important that the operator tune the transmitter to the proper frequency 548 pues usuen 81 912314 0 00 A13 82 130OMW 9 09n NV H3llM3dAL3131 xc ANM aN gt HOLMS NHOLO3T3S HOLMS 1531 3 5S p001 2 LINN M3LLINSNVHL SLOWSY YOLNGINLSIC YSdAL N3ALLINSNVHL Ou vWoLlnv N NOLVHOJNH3d3H HOIVHOMN3d 9n 02 95 DON 011 95 HOLWd HOLWd NOLLVOINNINWOD NOLLVOINDWINOO SnO3NVYTI3OSIW M 135 a syovwr 9NIdOO1 AN3lWdino3a 4 T di VNN3LNV QNV VNNALNV OL 2 2 RFCS RECEIVE SYSTEM The RFCS receive system shown in figure 2 19 is used to receive the transmitted signal and convert it back to a usable tty output Antenna Filter The antenna filter receives the rf sign
166. e pattern and enters them into the final approach During the final approach a precision radar tracks the aircraft Correct information pertaining to the approach is transmitted to the aircraft s autopilot When conditions are unfavorable for a landing the wave off control is initiated and the aircraft is guided through a short pattern and the landing approach is repeated Precision Course Direction The precision course direction mode is used in the remote guidance of bomber and reconnaissance aircraft and drones The guidance messages contain pitch bank heading altitude and airspeed commands to permit very precise control of the aircraft s flight path CARRIER AIRCRAFT INERTIAL NAVIGATIONAL SYSTEM CAINS The CAINS system is used to load alignment and way point data into aircraft on the flight deck or the hanger deck Aircraft alignment data consists of longitude latitude and ship s velocity data from the ship s inertial navigation system Way point data is a set of predetermined geographical points loaded into the aircraft s navigation computer Way points provide the aircraft with destination or target information When the CAINS system is used data can be loaded into the aircraft by either a hard wired system or RF radio transmission The hard wired insertion of data is accomplished when the aircraft is connected to a deck edge outlet box DEOB The pulse amplifiers of the AN SSW ID E can provide outputs for up t
167. e two address frames The call up message does not use start and stop codes ADDRESS CODE PHASE REF FRAME Figure 4 10 The NCS call up message NCS REPORT AND CALL UP MESSAGE This message shown i consists of the five frame preamble the phase reference frame the two frame start code the data frames containing the NCS report the two frame control stop code and two frames containing the address code for the next PU Phase Reference Message Data Length Varies Co ADDRESS CODE Figure 4 11 The NCS report and call up message PICKET REPLY MESSAGE The picket reply message shown in figure 4 12 consists of the five frame preamble the phase reference frame the two frame start code the data frames and the two frame picket stop code Phase Reference Message Data Length Preamble Figure 4 12 The picket reply message Short Broadcast Messages The Short Broadcast is a single data transmission to all members of a net by a station that maybe acting as either picket or NCS It 1s the same format as the picket reply message shown i The Short Broadcast message is manually initiated by the operator at the DTS Broadcast Mode Messages The Broadcast mode messages consist of a continuous series of short broadcast messages separated by two frames of dead time as shown in The message format is the same as a picket reply message In the Broadcast mode only one unit
168. e used for voice communications while the variable format messages are user defined in length and content Variable format messages are not used by the Navy JTIDS Architecture There are several features of the JTIDS architecture that have resulted in improved communications of the Link 16 system These features include the following Nodelessness Security Network participation groups NODELESSNESS A node is a unit required to maintain communications of a data link In Link 11 the NCS is a node If the NCS goes down the entire net 1s inoperative Link 16 does not need a dedicated station When the Link 16 net is established a single JU transmits a Network Time Reference NTR The time established by this unit is the network system time other units in the net use the message to synchronize with the network Once the NTR and the network have been established the network can continue to operate regardless of the participation of any particular unit SECURITY The security of the Link 16 system is vastly improved over that of the Link 11 system In Link 16 both the data and the transmissions are encrypted Data is encrypted by a 7 6 cryptovariable for message security The security of the data transmission is provided by the use of a second cryptovariable that controls the transmitted waveform Frequency hopping to prevent jamming is one of the features of the security system The transmission s
169. e usually either line of sight or tropospheric scatter LINE OF SIGHT LOS A line of sight microwave system consists of one more point to point hops Each hop 15 designed to be integrated into a worldwide communications network Los system characteristics are as follows Propagation Free space as affected by the tro posphere Communications Capacity Bandwidth Up to 600 4kHz voice channels wideband can accept TV Range Usually 50 to 150 km 31 to 95 statute miles This depends upon antenna height earth curva ture and intervening terrain e RF Power Usually less than 10 watts Antennas Both transmitting and receiving antennas are horn driven paraboloids providing high gain and narrow beam widths In some applications plane reflectors are used with the paraboloids IF OUT FOR HETERODYNE APPLIC ETV30024 Reliability Designed to be operational more than 99 of the time including the periods of poor propagation Countermeasures Because of antenna directiv ity the system is difficult to jam Additionally the sys tem should not be susceptible to nuclear disturbances of the 1onosphere e Application Because of the bandwidth capa bility and minimum site requirements los is well adapted to moderate distance point to point multichan nel communications with repeaters transmission of closed circuit TV transmission of radar information from outlying sites comm
170. e will then describe briefly the basic transmitters themselves 1 4 Table 1 2 Types of Radio Emissions F No modulation intended to carry intelligence AFTS MUX using single sideband suppressed carrier 9 F9 Cases not covered by above e g a combination of telephony and telegraphy 1 Fi On offor mark space keying without the use of a modulating tone 2 F2 On off or mark space keying of a modulating audio frequency or of the modulated emission Voice frequency modulating including simplex AFTS RATT A3A single sideband reduced carrier SSB A3B Two indpendent sidebands ISB Single sideband full carrier compatible SSB A3J Single sideband suppressed carrier 5550 A4 F4 Facsimile with modulation of main carrier directly or by a frequency modulated subcarrier Facsimile using single sideband reduced Carrier A5 FS Television ASC Television vestigial sideband F6 Four frequency diplex telegraphy RFCS RATT A7 Multichannel voice frequency telegraphy AFTS MUX Multichannel voice frequency telegraphy AFTS MUX using single sideband reduced carrier A7B Multichannel voice frequency telegraphy AFTS MUX using two independent sidebands Multichannel voice frequency telegraphy A9B Combinations using two independent sidebands MODULATION Modulation is the process of varying some charac teristic of a periodic wave with an external
171. eamble and phase reference frames During the second frame of the start code the DTS sets the output data request ODR active requesting the first word of the tactical data The CDS computer responds by placing 24 bits of data on the lines and then setting the output data acknowledge ODA The DTS samples the data and clears the ODR The first frame of data is processed for transmission and the ODR line is then set to request the next data word This procedure is repeated until all the data words have been transmitted Once the CDS computer has completed sending all the data words it will not acknowledge the ODR from the DTS If the CDS computer has not acknowledged an ODR from the DTS in a preset amount of time the DTS will clear the ODR line and generate a stop code Upon transmission of the two frame stop code the DTS will return to the receive mode Net Control Station NCS I O Operations The station acting as NCS follows the same protocols when communicating with the CDS computer Some differences exist in the generation of the control codes The net control station is responsible for interrogating each station Upon receipt of a picket stop code the DTS checks the next station address and sends an interrogation message After the interrogation message is transmitted the DTS waits to receive a start code from the interrogated station If a start code is not recognized after 15 frame intervals the station will be reinterr
172. eceived by the HPAG and amplified from 200 to 1 000 watts The HPAG can also operate in a low power mode in which case the output signal is about 200 watts The AIU provides the interface between the output of the HPAG and the antenna POWER INTERFACE UNIT There are two Power Interface Units PIUs in the equipment cabinet The fourth drawer 15 the HPAG PIU and the bottom drawer is the PIU for the R T and DDG The two PIUs are identical The three phase 115 VAC 60 Hz input power is converted to two outputs three phase 115 VAC 400 Hz and one phase 115 VAC at 400 Hz THE COMMAND AND CONTROL PROCESSOR The Command and Control Processor is a message distribution system designed to control and manage the interfaces between the three tactical data links Link AA Link 11 and Link 16 the operator and the hardware PURPOSE OF THE C2P The C2P controls and manages the interfaces between the various data links on major surface and aircraft Command and Control C2 platforms The surface platforms that will have the initial installations of the C2P system are aircraft carriers CV CVN and AEGIS cruisers CG followed by installation on amphibious assault ships LHA LHD and AEGIS destroyers DDG There are two configurations of the C2P one tailored for ships with the Advanced Combat Direction System ACDS Block 0 configuration and one for ACDS Block 1 configurations On AEGIS ships AEGIS Model 4 is similar to AC
173. eceiver Gain is a term used to describe an increase 1n current voltage or power For example if the detector which removes the desired intelligence requires 1 volt to op erate and if the input to the receiver is 1 microvolt a to tal amplification of 1 million is required before detection If the loudspeaker requires 10 volts another voltage amplification of 10 is necessary between the detector and the loudspeaker The gain of an amplifier 15 expressed in decibels dB The decibel is a means of measuring relative lev els of current voltage or power Most often it 1s used to show the ratio between input power and output power This ratio 1s expressed as gains and losses where a mi nus sign placed before dB indicates loss and a plus or no sign at all indicates a gain The number of decibels change between two power values can be com puted by the formula db log gt The comparison of dB s to power ratio is shown in table 1 3 You can see instantly the reason behind us ing the decibel system It is much easier to say the sig nal level has increased 40 dB than to say it has increased 10 000 times Examinirfg table 1 3 again you can see that an in crease of 3 dB indicates a doubling of power The re verse is also true If a signal decreases by 3 dB half the power is lost For example a 100 watt signal de creased by 3 dB will equal 50 watts while the same 100 watt signal increased by 5 dB will eq
174. ecurity also provides for the introduction of jitter and a pseudo random noise to be added to the waveform The addition of jitter and noise along with the frequency hopping makes the transmitted signal extremely difficult to detect and jam NETWORK PARTICIPATION GROUPS The time slots of a Link 16 network can be broken down into separate Network Participation Groups NPGs An NPG is defined by its function and determines the types of messages that are transmitted on it Some of the NPGs used by the Navy are as follows Surveillance Electronic Warfare Mission Management Weapons Coordination Control Fighter to Fighter Secure Voice Precise Participant Location and Identification PPLI and Status By dividing the net into NPGs each JU can participate on only the groups that support the mission of the unit Most Navy Command and Control units both ships and aircraft operate on all the defined NPGs except the Fighter to Fighter NPG Link 16 New Capabilities The increased size of the Link 16 enables the reporting of up to three times as much tactical information as was available under the Link 11 system Areas that have been improved under the Link 16 system include the following Number of Participants Track Numbers Track Quality Track Identification Friendly Status Granularity of Measurement e Relative Navigation Electronic Warfare
175. ed by the LMS 11 by setting the mean deviation to 45 degrees and the standard deviation to 90 degrees As with the mean deviation phase error this causes the bar to be painted in both quadrants of the graph Some causes of phase errors are noise simultaneous transmissions poor framing and errors in Doppler correction due to noise on the preamble For example a picket unit transmitting Net Sync during Roll Call will cause an error condition The expected value of the mean deviation is 0 degrees with a standard deviation of 5 degrees If only one tone has a mean value that 1s greatly different from the other tones it may be an indication of a frequency error on that tone SIGNAL POWER signal power is part of the amplifying information under the two bar graphs The signal power is the total signal strength in the 16 tones It is measured in dBm If no signal 15 received the default value of 51 dBm is listed SNR This is the signal to noise ratio It is measured in dB and calculated as the ratio of the average power in the data tones to the average power in the noise tones If the SNR value is preceded by the symbol gt it indicates that the average power in the noise tones is below the measurable threshold and the actual SNR is greater than the value indicated The maximum value that the LMS 11 can measure is about 34 dB An SNR that is greater than 30 dB is excellent If the SNR is less than 10 dB the data 1s
176. een the DTS and the crypto device could cause which of the following problems l One bit always set to a logic SL 2 One bit always set toa logro 3 All bits randomly set to a Logue iL 4 All bits randomly set to a LOG QE uua 41 20 rs 4 24 The multi station POFA is run 5 in which of the following modes Net test Ze dq gd 3 Broadcast J Short broadcast When a multi station POFA is run what total number of data words are in each block of data 4 26 transmitted a Ze 9 3 9 4 460 When a multi station 15 runs LL units Participating LB the test should be positioned ds within how many miles of each other lae Zu 90 Su 99 d dO A multi station POFA should be run using which of the following frequencies 4 28 1 Any HF frequency 2 Any UHF frequency 3 The current operational frequency only 4 The current secondary frequency only Ihe multi station POFA should be run for what minimum amount of time 1 5 minutes 7 minutes 3 10 minutes 4 15 minutes At the completion of the multi Station the technician should record which of the following information on the error prrntouE 1 Distance and bearing of all PUS 2 Frequency used 3 Start and stop time of the POFA 4 All of the above 24 A multi station POFA should be considered successful when the link quality factor 1s wh
177. el I 50 watts 2 100 watts Je 1050 8 4 200 watts What shipboard system is used to receive Fleet Satellite Dp Broadcast I AdS BRE 1 2 AN SRR 1 3 ANZSSR 1 4 AN BRR 1 Which of the following is a spread spectrum type modem and is used with the AN FSC 79 2 934 satellite communications terminal 1 OM 33A USC 2 OM 43A USC 3 OM 51A FR 4 OM 61A FR Of the two processors listed below which one is used in the TADIXS subsystem 1 AN UYK 20 2 AN UYK 44 V 10 The AN USQ 69 V data terminal set is currently used with what two subsystems ly SSIXS OTCIXS 2 TACINTEL NAVMACS 3 NAVMACS TADIXS 4 JOICIXS TIADIXS Audio digital converter 58 Used primarily as an analog to digital converter for what type of communica tions Analog voice Crypto voice Secure voice Unsecured voice CO DRO Fe Where are the system interface connectors installed on the Electrical Equipment Rack CY TISTI WSC 3 1 On the back panel 2 On the front panel 3 On the side panel 4 On the top panel DAMA equipped shore installations use the OK AB LIV VZ7 ESC Control Monitor Group Eo anteriace 1D 1271B7Us AN WSC 5 V s and baseband equipment It can accommodate up to how many TD 1271B Us GN m Textbook Assignment ASSIGNMENT The Link 11 System chapter 4 gt pages 4 1 through 4 18 DEA 2534 1000 Digitek Compuce
178. el frequency synthesizer receiver synchronizer coder modulator demodulator and two power supplies Data Processing Set AN UYK 20 V The AN UYK 20 V figure 3 30 is a general purpose processor designed to meet the requirements of small and medium processor applications in shipboard or shore military facilities The processor is used in the CUDIXS NAVMACS SSIXS shore installations and TACINTEL subsystems Data Processing Set AN UYK 44 V The 44 figure 3 31 was designed to meet the same requirements as the AN UYK 20 V and to use AN UYK 20 V software with minimum modifications It is used in the TADIXS subsystem pem 4 nnt rtt Figure 3 31 Data Processing Set AN UYK 44 V 3 30 Communication System Control Center AN USQ 64 V This control center is used to pass satellite data traffic efficiently and bidirectionally between a ship and shore It turns associated transmitters on and off according to a polling scheme It also uses detection and correction and sends automatic requests for retransmission to improve received data accuracy The ten AN USQ 64 V variations and their uses are as follows V I SSIXS shore installations V 2 CUDIXS shore installations V 3 SSIXS subscriber installations V 4 NAWCS shore installations V 5 TACINTEL ship subscriber for passing Special Intelligence 51 data traffic bidirectionally between a NCTS and fleet nets
179. ely 24 hours In addition to receiving grade results for each assignment you will receive course completion confirmation once you have completed all the assignments To submit your assignment answers via the Internet go to http courses cnet navy mil Grading by Mail When you submit answer sheets by mail send all of your assignments at one time Do NOT submit individual answer sheets for grading Mail all of your assignments in an envelope which you either provide yourself or obtain from your nearest Educational Services Officer ESO Submit answer sheets to COMMANDING OFFICER NETPDTC N331 6490 SAUFLEY FIELD ROAD PENSACOLA FL 32559 5000 Answer Sheets All courses include one scannable answer sheet for each assignment These answer sheets are preprinted with your SSN name assignment number and course number Explanations for completing the answer sheets are on the answer sheet Do not use answer sheet reproductions Use only the original answer sheets that we provide reproductions will not work with our scanning equipment and cannot be processed Follow the instructions for marking your answers on the answer sheet Be sure that blocks 1 2 and 3 are filled in correctly This information is necessary for your course to be properly processed and for you to receive credit for your work COMPLETION TIME Courses must be completed within 12 months from the date of enrollment This includes time required to r
180. enables the connection of each of the digital to digital converters DDC to one of two different computers The control panel for the coordinate data transfer control assembly is shown in figure 6 5 The COMPUTER SELECT provides switching such that DDC A 15 connected to computer 1 and DDC is connected to computer 2 or vice versa Either of the two DDCs maybe connected to its monitor test panel for off line testing The DDC output options are the CDS old NTDS radio set the CAINS system or the test mode Digital to Digital Converter The digital to digital converter assembly provides system timing converts parallel data from the CDS computer into serial data for transmission by the UHF radio set and converts serial data received from the radio set into parallel data for input to the CDS computer The DDC is the heart of the data terminal set Monitor Test Panel The monitor test panel provides the technician with a means to monitor Link 4A operations and off line testing capabilities There is one monitor test panel for each DDC Pulse Amplifier The pulse amplifiers provide level and signal conversion functions to allow the AN SSW ID E data terminal set to drive the serial output for the UHF radio set and the deck edge outlet boxes for CAINS COMMUNICATIONS SWITCHBOARD The communications switchboard interconnects the AN SSW 1 to the UHF radio sets The communications switchboard is similar to the Link 11 switchboard descr
181. ened message traffic is sent to the teletypewriter or TDP system as applicable The rest of the traffic is discarded The reception of traffic does not make the satellite link controller send an acknowledgement This allows afloat platforms to receive traffic while Operating in an emission control EMCON en vironment DEMAND ASSIGNED MULTIPLE ACCESS DAMA SUBSYSTEM The uhf DAMA subsystem was developed to multiplex several baseband systems or users on one 25 kHz satellite channel This had the effect of adding more Satellite circuits per channel to the uhf Satellite Communications System Without uhf DAMA each satellite communications subsystem requires a separate satellite channel DAMA equipment accepts encrypted data streams from independent baseband sources and combines them into one continuous serial output data stream DAMA interfaces the Navy uhf SATCOM subsystems and the AN WSC 5 V and DAMA compatible AN WSC 3 V transceivers The DAMA unit TD 1271B U multiplexer includes a modem eliminating the need to use a separate modem at the AN WSC 5 V or the modem within the AN WSC 3 V The baseband equipment input or output I O data rate with DAMA equipment can be 75 300 600 1200 2400 4800 or 16 000 bps The DAMA transmission rate on the satellite link burst rate can be 2400 9600 19 200 or 32 000 symbols per second sps CUDIXS NAVMACS Secure Voice and OTCIXS currently use 2400 bps TACINTEL operates at 2400 or
182. ent groups subsystems and their interrelationship There are two versions of SAS an automated system ASAS and a manual system MSAS The voice switching equipment and means provided for user control over circuit selection are the two primary differences Information in this section applies to both ASAS and MSAS unless otherwise specified There is no specific list of equipment that makeup every SAS installation There can be different types and quantities of equipment in each of the groups identified in Equipment types and quantities are dictated by the communications requirements of individual ships and ship classes The publication Operation and Maintenance Instructions Single Audio System NAVELEX EEI09 CA OMI 010 110 SAS identifies in tables 1 1 and 1 2 the SAS equipment commonly used in the fleet EQUIPMENT USER VOICE CRYPTO STATION SWITCHING PLAIN SUBSYSTEMS SYSTEM CAPABILITIES The SAS incorporates basic capabilities for setting up and operating voice communications circuits An SAS installation provides the unique capability to communicate in a secure or nonsecure mode at the discretion of the operator from a single telephone or NTDS device This single audio interface with various crypto or plain subsystems is the essence of the SAS The SAS provides the following options e The user can select the transmit operating mode except for FLTSATCOM secure voice and PLAI
183. ent by simultaneously using four The normal configuration for multi link operations frequencies frequency link operations uses three HF and one UHF frequency To implement this option three additional processor boards are installed in the data terminal Each data terminal board is connected to a separate radio as shown in figure 7 3 Muse se gt RADIO RINT AP lUSB JLSB RADIO EN HEUS EHE 4 qu 38NP0174 Figure 7 3 Block diagram of the AN USQ 125 data terminal configured for multi frequency link operations During the Link 11 receive cycle each data terminal board demodulates the link signal and sends the data to the master processor board The master processor compares the received data and selects the signals with the fewest errors to send to the CDS computer Although this mode is normally used with three HF frequencies and one UHF frequency there is no set limitation of the radio configuration 7 3 On line and Off line System Test Options The data terminal provides several options for both on line and off line testing These include the following radio echo test loopback tests 1 2 3 and 4 and DTS fault isolation tests The radio echo test loopback test 1 and loopback test 4 are on line tests while loopback test 2 loopback test 3 and the DTS fault isolation tests are off line tests RADIO ECHO TEST When this option is selected the data te
184. entered just under the LMS 11 mode In figure 5 6 this is RC FAST This means the link is in Roll Call mode fast data rate The right side of the header displays the date and time The left side of the header information allows the operator to enter the NCS address and the sideband to monitor The LMS 11 uses the address 77 as a default for NCS However recall from that 77 is an illegal address and would not be used in an active link Since NCS never sends an interrogation to itself the LMS 11 uses this address to designate NCS The display sweeps from left to right and from top to bottom The display is color coded and uses a stair step pattern that is easy to understand The display of a single NCS report and the meaning of the colors and levels is shown in figure 5 7 Figure 5 8 shows how the different messages appear on the LMS 11 link monitor screen Note that the NCS 5 10 report ends with the interrogation of the next PU in the polling sequence LINK MONITOR NCS 77 RC FAST DATE 8 6 89 oe SUE 2 13 SIDEBAND USB LSB DIBV 154 164 m m uie m a a mmm mm a 156 164 164 m 4 ENS __ 56 M ul QM mm ______ 0 NEL __ 38NP0199 Figure 5 6 The link monitor display screen Study 5 6 again and follow the polling sequence of the four units in the net The last report on the top line is an NCS report and call to PU 04 This is followed b
185. eo Simultaneously which of the following cables would be best Suited to the system Twisted pair Shielded twisted pair CO BRO Fe Baseband coaxial Which of the following types of cable 1S immune to interference from electrical and electronic devices Fiber optic Baseband coaxial Shielded twisted pair Telephone cable He CO RY Which of the following devices provides the interface between the LAN and a personal computer Network server NIC Disk server Cables CO DO Lm Which of the following devices 0 925 is used to manage the shared resources of the LAN Network server NIC Disk server Network monitor N e Early disk servers suffered from which of the following problems 1 Lack of security 2 No data organization 3 No disk management 4 All of the above 34 Broadband coaxial 6 530 Ensuring data integrity by preventing multiple users access to the same record at the same time is known as what process File locking Field locking Record locking Disk LOCKOUL rs CO BO Which of the following servers was developed to provide reliable disk management in a LAN Disk server Print server File server Network server ROGO La Which of the following functions is NOT performed by the file server 1 Routing files to a central printer for printing 2 Processing of the network control software 3 Converting high level disks c
186. equency 8363 kHz No receiving equipment is included AN PRC 70 The AN PRC 70 is a multimode FM CW FSK SSB AM manpack radio set operating in the 2 0 to 75 9999 MHz frequency range AN PRC 77 The AN PRC 77 shown i is an FM short range 920 channel vhf radio operating in the 30 to 75 95 MHz frequency range Figure 2 22 view A shows the pack frame the handset and accessory pouch View B shows the transmitter receiver When not in use the equipment is stored in a special aluminum case ETV30034 Figure 2 22 Radio Set AN PRC 77 2 25 AN PRC 96 The AN PRC 96 portable transceiver shown in figure 2 23 is dual channeled battery powered and provides homing and two way voice communications between liferafts and searching ships and aircraft on the 121 5 and 243 MHz guard channels AN PRC 104 The AN PRC 104 shown in figure 2 24 15 lightweight radio transceiver that operates in the hf band and can be tuned from 2 0 to 29 9999 MHz It operates in the ssb usb lsb modes for voice a communications CW for Morse code and FSK for TO TALK CODE qum um TEST Figure 2 23 Transceiver AN PRC 96 AMPLIFIER COUPLERS 4 gt CX gr a KOSI rn sS Wear RECEIVER lt eL EXCITER A RUM 1 WHIP 19 nl M ANTENNA SS JE nee M 1 Rm IE A ww Qh all LC i S
187. er be passed around the ring unless the failed node is either physically or electronically bypassed Using bypass software the network can withstand the failure of a workstation by bypassing it and continue to maintain the integrity of the network One of the major issues in a ring topology is the need for making sure all workstations have equal access to the network One of the major disadvantages of ring topologies is the extreme difficultly of adding new workstations while the network is in operation Normally the entire network has to be brought down while a new node is added and cabling reattached However this particular problem can be overcome by the installation ___ _____ pce Cmm ______ NETWORK NENNEN SERVER PC 3 PC 5 m A m 1 e _______ __ L qum I mn iii m mL 300MB UE PRINTER eae uanp pisx po LLILL IET Isi L PRINTER HARD DISK CAN BE SHARED BY M ALL USERS ON A FILE BASIS Figure 8 4 distributed star tree network topology 8 9 of additional connectors when the network is initially set up These connectors enable you to add or remove nodes while the network remains intact and in operation ACCESS METHODS Another decision the designer makes is that of which access method to use Access methods are the arrangements used
188. er an HF radio or a UHF radio Long range communications are achieved by the use of the HF system UHF communications are limited to line of sight Line of sight means the radio wave will not bend over the horizon therefore the use of an antenna mounted high on the mast will increase the range of UHF communications Antenna Couplers Antenna couplers are used to connect a specific radio set to a specific antenna The coupler provides for the correct impedance matching of the antenna and the radio set For many of the multicouplers to work properly it 1s extremely important that the correct frequency spacing be observed A general rule is to ensure a frequency spacing of 15 percent Frequencies that are too close together can cause interference and distortion increasing the signal to noise ratio and causing bit errors in the data Antennas In oversimplifying the theory of antenna Operation an antenna is just a piece of wire that radiates electromagnetic energy from the radio into the atmosphere and converts atmospheric electromagnetic radiation into RF current to be processed by the radio As electromagnetic energy from the atmosphere passes through this wire it induces a current in the wire This current is fed to 4 4 the radio receiver If the receiver is tuned to the same frequency as the received signal the signal can be processed The same wire will radiate an electromagnetic field if current is flowing through it
189. er equipment and vise versa Let s take a look at a typical microwave transmitter and receiver MICROWAVE TRANSMITTER A typical microwave transmitters shown in figurel 2 11 In operation the output of a telephone multiplex terminal which consists of a frequency multiplexed AM carrier signal is applied to the terminal transmitter This input signal baseband signal also could be a television signal or any other form of signal to be transmitted A pre emphasis network accentuates the high frequencies relative to the low to improve the 2 10 BASEBAND INPUT PREEMPHASIS NETWORK PILOT INSERTION OSCILL AMPLIFIER PILOT DETECT ISOLATOR AFC REF lt OUTPUT FILTER POWER gt ALARM ETV30023 Figure 2 11 Typical microwave transmitter signal to noise ratio The insertion amplifier accepts portion of the output power back to the klystron to the signal amplifies it and then applies the signal to the compensate for its nonlinearity This technique allows klystron oscillator With this method the input signal for optimum performance with modulation densities as directly modulates the carrier frequency resulting in a high as 1200 channels You should be aware that solid frequency modulated wave The linearize couples a state devices are replacing most klystrons 2 11 MICROWAVE RECEIVER A typical microwave receiver is shown in figure Though not shown sensin
190. er ig Se 0 k ERA Pee 5 AE C CCo IE Nee ETV30012 Figure 1 12 Receiver Transfer Switchboard SB 973 SRT signed to move small loads or to produce small amounts of torque When the shaft to be driven at the remote location is connected to an indicating device or some light load the synchro receiver is capable of de veloping the necessary torque But if the load is a heavy load and more torque is required torque power amplification 15 required control system capable of delivering larger amounts of power or torque is known as a servo mechanism or servo You will encounter many systems that use sychros and servos You can find detailed information about these devices in the Military Standards Handbook MIL HDBK 225 and NEETS Module 15 Synchros Servos and Gyros NAVEDTRA 172 15 00 85 2 SYSTEMS EQUIPMENT CONFIGURATIONS INTRODUCTION In chapter 1 we discussed basic system requirements In this chapter we will look at each equipment configuration We will then link them together forming a block diagram of the systems covered We will discuss naval equipment from extremely low frequency through super high frequency We also will look at microwave communications the Single Audio System teletype equipment portable and pack radio equipment and the Communications Link Interface Planning System At various points in the chapter we review basic principles associated with the larger top
191. erationally the user terminal will have its baseband port automatically connected to a data time slot when the proper slot number is keyed into the multiplexer front panel keyboard Each SATCOM subsystem that uses DAMA will have a specific slot number Circuits will normally be operated on a netted basis and circuit numbers will be assigned by COMNAVTELCOM and or FLTCINC Transition Transition to DAMA is taking place in a manner that allows subscribers converted to DAMA to communicate with those who have not been converted During the transition period equipment installed at shorebased master stations will form gateways between DAMA and non DAMA circuits In the following paragraphs we will discuss subsystems that are either currently undergoing conversion to DAMA or are planned for conversion so you will know what to expect in the future Secure Voice DAMA is now being phased into the Secure Voice Subsystem A DAMA configured Secure Voice Subsystem is shown in figure 3 12 CUDIXS NAVMACS NAVMACS platforms will be gradually transitioned to DAMA This transition will start when CUDIXS shore and CUDIXS NAVMACS ship hardware and software have been modified for compatibility with DAMA At that time a transition will begin allowing DAMA or non DAMA ships to communicate with the CUDIXS shore terminal DAMA configured CUDIXS NAVMACS subsystem is shown irl figure 3 13 Teletypewriter Teletypewriter capability via DAMA
192. erator on the NCS platform and continuously transmits the Link 11 preamble until stopped by the operator The preamble consist of two 605 Hz tone and the 2 915 Hz tone During the transmission of Net Sync the 2 915 Hz tone is periodically phased shifted 180 degrees The time between these shifts is determined by the selected data rate and is called a frame Each PU is equipped with a very accurate time base in the form of a frequency standard internal or external When the NCS transmits Net Sync each unit receiving the transmission synchronizes its individual time base with the Net Sync signal If the picket station is operating in the corrected sync mode as is normally the case the picket will check to see that it can recognize the Net Sync signal as a means of verifying that a good radio link has been established If a picket 1s going to operate in the stored sync mode it will align its stored frame timing to the timing of the NCS using the received Net Sync signal Since stored sync timing locks the picket to the time base of the NCS data from other pickets may be lost Therefore this mode should only be used during times of poor radio propagation or signal jamming After the completion of Net Sync the next operation performed in establishing a link is usually Net Test Net Test Net Test provides an overall evaluation of the net and equipment performance When you are operating in this mode NCS will broa
193. erms associated with tty and FAX equipment We will then look at some basic systems MODES OF OPERATION There are two basic modes of teletypewriter Operation asynchronous start stop and synchronous The asynchronous mode is the most common The synchronous mode 18 used primarily in high speed data systems Asynchronous Mode In this mode the receiving device is only allowed to run for one character and is then stopped to await the start signal for the next character Any differences in speed between the transmitting and receiving devices can only accumulate during the time assigned to one character There is a penalty for this advantage Character length is increased to include the start space and stop mark signals These start and stop signals are part of the five unit code BAUDOT CODE shown in figure 2 14 Synchronous Mode Synchronous systems have an advantage over asynchronous systems The start and stop elements are not used This allows more room for information transmission Time is not wasted on start and stop units Additionally this mode has a higher capacity to accept distorted signals because it does not depend on the start and stop signals for timing MODULATION RATE The terms used in referring to tty modulation rates or signaling speeds are baud words per minute wpm and bits per second bps Baud 1s the only term that 1s technically accurate The others are either ap proximations or require expla
194. erno T sees 783030238 yO W3OON Sd I eee MO dud gt aes EE ING 7 3 SOSM NY ONS OSN eri No ae pog Pb Ose i T SOSM NY WSCON TPL FP F Y30NOOSY p L i au oaJdd un a EN 1 A sxiano NIIS 69 DSh NV SYOHS wagiuosans 13S Lc P m S 19 79 SUN WNINYSL VIVO C ETV30043 3 8 azt communications These improvements help increase message traffic through put rates and traffic volume and improve link reliability Figure 3 5 shows both sides of the CUDIXS NAVMACS subsystem Message Traffic Input At shore facilities the primary collection point for message traffic to be transmitted or received on the CUDIXS NAVMACS rf link is NAV COMPARS Rf transmission Link Control Non DAMA The CUDIXS baseband equipment shares a common rf terminal with other subsystems At the shore facilities this terminal is a uhf transceiver AN WSC 5 V Aboard ship NAVMACS uses a uhf transceiver AN WSC 3 V All uhf satellites have 25 kHz wide channels allocated for CUDIXS
195. errr pom TRANSMITTER 4 4 PATCHING 9 4 Annan Me RECEIVER PANEL GROUP v pu pod 83 4 TRANSMITTER XMTR TTY RECEIVER es CONTROL TY set TRANSFER idis YNI SWBD Figure 2 17 Simplex RFCS system 2 19 RFSC SEND In the following paragraphs we will discuss the equipment shown in the RFCS transmit send system in figure 2 18 Teletypewriter Sets The Model 28 family and the AN UGC 143 series are the two tty sets currently used by the Navy Although the AN UGC 143 is not shown in figure we will discuss its characteristics later There are several tty sets included in the Model 28 family with varying weights and sizes They feature high operating speeds quiet operation and are particularly suited for shipboard use under the severe conditions of roll vibration and shock Model 28 tty s may be composed of the following components depending upon their specific function a cabinet keyboard page printer typing perforator transmitter distributor typing reperforator power distribution panels and power supply equipment components are housed in the cabinet Transmissions are initiated through the keyboard or transmitter distributor Received signals are printed on the page printer Monitored transmissions can also be printed on the page printer The typing perforator a
196. ertor are needed to change the rf signal back to dc pulses RADIO ACTUATED TELETYPE RATT SYSTEMS The Navy s two basic RATT systems are the tone modulated system known as audio frequency tone shift AFTS and the carrier frequency shift system known as radio frequency carrier shift RFCS The RFCS sys tem is commonly called frequency shift keying fsk For fsk systems the transmitter provides a source of rf excitation Figure 2 15 illustrates a basic fsk DDIC ANILAR SHIFT SYSTEM TRANSMIT n FREQUEN CARRIER FREQUENCY SHIET MOD ATEA OU WAVE FREQUENCY SHIFT KEYER DIRECT CURRENT a U MARK arg ami NE NM R F OSCILLATOR WAVE gt a 1 hit 5 0 irn 453 iss Las L F XMTR A ee Re ens ge mitti nid FREQUENCY SHIFT CARRIER CARRIER FREQUENCY SHIFT SYSTEM RECEIVE WAVE MARK SPACE r oe IN SIGNALS Revere SJ ELECTRICAL a RECEIVER M IMPULSES TTY Ran Cu ium ETV30027 Figure 2 15 Basic carrier frequency shift RFCS system 2 17 system You will find that the is part of the amplitude modulates the transmitter carrier wave The transmitter in modern systems The keyer shifts the
197. esigned for special intelligence communications lie ORCEXS zs 1 5 3s TACINTEL 4 FLTSATCOM TADIXS equipped surface ships and submarines operate in what mode s 1 Receive only 2 Transmit only 3 Transmit and receive What subsystem is used in conjunction with TADIXS to transmit OTH T data from the fleet to other ships and shore commands Ig sOTCIXS Zu dep 3 TACINTEL 4 FLTSATCOM Because the reception of TADIXS information by a ship does not require an acknowledgement the ship can l operate in what type of environment and still receive message traffic EMSS control Emission quiet control Transmit quiet H CO N FO What system was developed to multiplex several users on one 25 kHz satellite channel MSAS DAMA VINSON NCTAMS A w N e 23394 2500 zc 295 2 539 What term is used to describe ER how the Demand Assigned Multiple Access data stream is formatted 1 Frame 2 Picture gt segment 4 Window 2 40 In the DAMA multiplexed data Stream which slot is used to error le 2e LINK 3 Ranging 4 Return channel What are all DAMA multiplexer pee transmit tames referenced to ls The wontroller 2 The satellite 3 The transmitter 4 The Vocoder Wheeh oft the 261 equipments is used as the DAMA PAN multiplexer le DMSIZITBAU 2 TD 1271B U 3 DM 1271B U 4 TD 1217B U Who performs day to d
198. esubmit failed assignments PASS FAIL ASSIGNMENT PROCEDURES If your overall course score is 3 2 or higher you will pass the course and will not be required to resubmit assignments Once your assignments have been graded you will receive course completion confirmation If you receive less than a 3 2 on any assignment and your overall course score is below 3 2 you will be given the opportunity to resubmit failed assignments You may resubmit failed assignments only once Internet students will receive notification when they have failed an assignment they may then resubmit failed assignments on the web site Internet students may view and print results for failed assignments from the web site Students who submit by mail will receive a failing result letter and a new answer sheet for resubmission of each failed assignment COMPLETION CONFIRMATION After successfully completing this course you will receive a letter of completion ERRATA Errata are used to correct minor errors or delete obsolete information in a course Errata may also be used to provide instructions to the student If a course has an errata it will be included as the first page s after the front cover Errata for all courses can be accessed and viewed downloaded at http www advancement cnet navy mil STUDENT FEEDBACK QUESTIONS We value your suggestions questions and criticisms on our courses If you would like to communicate with us regarding this co
199. fied PU 3 Real time link activity 4 A graphic representation of the power levels of the received Link 11 tones from a single PU 23 Which of the following function keys on the LMS 11 keyboard would the operator depress to select the link monitor mode 1 LM Zu NET Su PECL JEU A PU address of 77 is used by the LMS 11 to indicate which of the following units if any PU 7 NCS Task force flagship None 77 is illegal address Ww N e IN ANSWERING QUESTIONS 4 46 THROUGH REFER TO FIGURE 5 7 IN THE TEXT which of the following colors indicates the preamble on the link monitor screen of the EMS 11 1l Yellow 2 Red c Oyan 4 Green A small cyan line in the middle of the data field indicates the LMS 11 has detected which of the following signals 1 Start code 2 Stop code 3 Phase reference frame 4 Noise Which of the following displays is used to indicate the LMS 11 is listening 1 A thick blue line 2 thin blue line 3 A thick red line 4 thin red line The phase reference frame is 4 53 displayed on the link monitor display in what manner 1 As a small green line between the start code and the data 2 As a small red line between the start code and the data 3 As a small green line between the preamble and the start code 4 As a small red line between 4 54 the preamble and the start code Data frames are represented on the Lznk moniLor display by which of the follo
200. for relative power is also color coded When the relative power of a data tone is dB the bar is green If the power level is in the range of 1 to 2 dB or 1 to 2 dB the bar will be yellow The bar is red if the power level is greater than 2 dB or less than 2 dB The length of the bars plotted on the graph is rounded off to the nearest 1 2 dB PHASE ERROR DEGREES The phase error degrees bar graph shows the mean and the standard deviation of the Link 11 tones The standard deviation of a tone 15 plotted by a color bar on the graph The size of the color bars is plotted to the nearest whole degree of deviation The mean deviation of the tone is indicated by a small white line usually in the center of the standard deviation color bar The mean phase error should fall between 45 degrees and 45 degrees If the data is bad the mean phase error is set to 45 degrees and the standard deviation is set to 90 degrees This causes the bar to be drawn across both quadrants of the graph The standard deviation is represented by a color coded bar for each tone A green bar is displayed if the standard deviation is within 10 degrees Deviations between 10 degrees and 20 degrees are represented by a yellow bar and deviations greater than 20 degrees are red The standard deviation must be a positive value that is less than 45 degrees If the standard deviation is out of range for a given tone the data is bad This condition is indicat
201. g and alarm functions are integral to all microwave communications equipment During system operation the signal from the an tenna passes through a waveguide preselector that eliminates interference from adjacent rf channels The signal then enters a waveguide filter tuned to its fre quency which rejects all other unwanted frequencies Next the signal passes through an isolator that minim izes intermodulation noise and holds the VSWR below 1 2 1 The signal is then mixed with the local oscillator LO output to produce the standard 70 MHz inter mediate frequency IF The IF output is amplitude limited and applied to an automatic frequency control afc discriminator which controls the frequency of the LO The signal is also applied to an IF discrimina tor a de emphasis circuit and a squelch circuit that disconnects the baseband amplifier and demultiplex ing equipment if noise increases above a preset level After the squelch circuit the signal passes through a baseband amplifier and then to the demultiplexing equipment where the original intelligence is retrieved Microwave communications systems operating in the shf portion of the frequency spectrum use the l ll Z gt SELECTOR b ISOL MIX m FILTER di principle that propagation approaches an optical straight line path Propagation takes place in the lower atmosphere and is affected by meteorological factors Communications in this medium ar
202. gure 3 37 Time Division Multiplexer TD 1150 USC multiplexing of several digital data sources over one satellite channel This allows platforms equipped with the TD 1271B U and proper RT equipment to time share the satellite channel Each multiplexer has four I O ports for connecting baseband equipment and four remote request and status display units The TD 1271 B U interfaces with RT equipment on a 70 MHz IF Outputs from the unit also control the frequency and synchronize the transmit and receive timing of the radio A TD 1271B U is shown i TSEC KGV 11 LOCATION if dr Jot iis 2 B T MES 6 fF a 9 v Figure 3 39 Multiplexer Mini DAMA AN USC 4X V prototype Multiplexer Mini DAMA AN USC 42 V 1 V 3 This unit is currently under development with technical and operational evaluation to take place soon Mini DAMA 15 compatible and interoperable with the TD 1271B U and will perform or eliminate all functions of the AN WSC 3 V 2 V 3 A Mini DAMA unit is shown in figure 3 39 Cryptographic Equipment Several different models of cryptographic equipment are used in the FLTSATCOM system Check your command s communications configuration for identification of this equipment Specific information on this equipment is available on a need to know basis Electrical Equipment Rack CY 7597 WSC 3 CY 7597A WSC 3 The CY 7597 WSC 3 fig 3 40 and CY 7597A WSC 3 provide for mo
203. h the net can be easily detected in real time and you can determine the cause of the problems by evaluating the different displays When the cause is determined the operator or technician can take corrective action System Initialization When the LMS 11 is turned on following the correct power up sequence the computer runs a group of self tests and it then boots the disk in drive 0 When the booting is complete the LMS 11 monitor displays the following message BOOTING COMPLETE SWITCH TO RGB At this time the operator should depress the RGB button on the monitor The Initialization display is the first screen displayed after the software is loaded The operator can also recall the Initialization display by pressing the INIT button of the keyboard The Initialization display screen is shown in figure 5 5 During the initialization process the operator 15 required to enter the following Link 11 operating parameters 5 9 DATE and TIME PRINTER Selects which printer if any is being used with the LMS 11 e NET MODE Selects the Link 11 mode Net Sync Net Test Roll Call Broadcast or Short Broadcast The default 1s Roll Call DATA RATE Selects whether the link is operating in the fast or slow data rate FREQ CORR Enables or disables Doppler correction CALL TIMEOUT Allows the operator to specify the number of frames for the missed call timeout Normal link operations is 15 for frame
204. h tone in dB The highest value of the scale is 0 dB and decreases to 40 dB The tone with the greatest amount of power is set to 0 dB on the scale This should be the 605 Hz tone The remaining tones are measured relative to the tone with the greatest power A single blue line is drawn horizontally across the screen at the 6 dB level Ideally all data tones should extend up to this line The 605 Hz tone and the data tones are displayed by solid green vertical lines If the power of a data tone is greater than 6 dB with respect to the 605 Hz tone the area above the 6 dB line is indicated by an open yellow bar on top of the green bar If the power level of a data tone is below the 6 dB threshold an open yellow bar is used to fill in the remaining distance This allows the operator to view the effects of the noise The power of the noise tones is also indicated by open yellow bars To enter the spectrum display depress the SPECT key on the keyboard Several options are available to the operator by entering data into the header fields of the spectrum display The operator may designate the address of the NCS The default address is 77 The Operator can also select a particular sideband USB LSB or DIV for display By using the RESTRICT field the operator can restrict the display to only data frames or only preamble frames or choose no restrictions The PU field allows the operator to designate a particular PU for display If 00 is en
205. he picket station The range entered into these switches causes the DTS to alter the frame timing to compensate for the signal propagation delay between the picket station and NCS The range in miles setting for the NCS is always zero miles Address Control Indicator The address control indicator is used to set the address of the picket stations to be interrogated when a unit is configured to operate as the NCS The address control indicator is shown in figure 4 17 The address control indicator consists of 20 identical address selection modules which are used to address up to 20 stations More than one address control indicator may be installed in a system to provide the ability to interrogate more than 20 stations Each address selector module has two thumb wheel switches in which one of 64 octal addresses may be entered address 00 and 77 octal are invalid Also each address selector module has a power on off switch a power on indicator lamp and a call indicator as shown in figure 4 18 When a unit is configured as the NCS the operator enters all the assigned addresses of the net participating units into the address selector modules and turns on each module with a valid address Once the roll call mode 15 initiated the DTS will check each module sequentially If the power of the module is on and a valid address is entered the address is sent to the DTS for use in an interrogation message If the power switch is in the O
206. he receive signal is picked up by the antenna and fed to the receive side of the transceiver through the antenna coupler The receiver output is connected to an SB 973 SRR receiver transfer switchboard It is then connected to either the nonsecure or secure voice system depending upon the received transmission mode When a nonsecure signal is received the output of the receive transfer switchboard is fed to either the radio set control or to the AM 3729 speaker amplifier or both depending on user preference If a secure voice transmission is received the output of the switchboard is connected to the secure ANTENNA RECEIVER COULER RECEIVER TRANSFER SWITCHBOARD AN SRA 33 AN SRC 20 SB 973 SRR OR OR OA 9123 SRC AN SRC 21 OR AN WSC 3 ETV30021 VOICE EQUIPMENT voice equipment and decrypted This output is fed to the secure voice matrix The secure voice matrix output is fed to the RPU where the signal is converted back to its original form SUPERHIGH FREQUENCY COMMUNICATIONS As we discussed in the previous chapter two primary uses of the superhigh frequency shf band are microwave and satellite communications The AN FSC 79 SHF terminal and satellite com munications will be covered in the next chapter In the following paragraphs we will discuss line of sight and tropospheric scatter microwave communications MICROWAVE COMMUNICATION SYSTEMS Microwave systems such as the AN FRC 84
207. her the problem 15 local or if the entire net is experiencing problems Because of the complexity of link equipment a variety of methods were used over the years to solve link problems If a particular action worked once it was often assumed that it would work in all instances Over the years this led to a type of folklore or mythology on how technicians were to troubleshoot the link Senior link techs would pass these myths 5 1 on to junior link techs and the mythology developed a life of its own In the following paragraphs we examine some of these myths and seek to clarify the real problems that led to the evolution of them Myth Changing the NCS Will Always Solve Net Problems Changing the NCS may solve net problems but only if the current NCS is causing the problem What is the problem If data is not being received from a unit because the current NCS has entered the PU number incorrectly shifting NCS functions to a station with the PU data entered correctly will solve the problem However it would be easier if the current NCS were simply to enter the correct PU numbers When the current NCS is using a radio set with poor receiver sensitivity and is polling on top of picket responses effectively jamming the entire net changing the NCS is imperative Also if several units are not recognizing their interrogations because NCS is out of range or in an RF propagation shadow changing to a unit in a better location should improve net co
208. ibed in chapter 4 of this manual LINK MONITOR SYSTEM LMS 4 The LMS 4 provides stand alone Link 4A monitor and readiness check capabilities and its operation is similar to the LMS 11 covered in the previous chapter The monitor function listens passively to the Link 4A communications between the control station and the controlled aircraft Signal analysis and test message validity are performed on the data The readiness check function tests the readiness of the control station to conduct live two way Link 4A operations Control messages transmitted by the control station are monitored and the LMS 4 generates the reply messages required to maintain two way communications 7 NEW TECHNOLOGY IN DATA COMMUNICATIONS INTRODUCTION The current Link 11 and Link 4A systems are being updated with new equipments The Data Terminal Set AN USQ 125 is currently replacing the older Link 11 data terminals In addition new communications systems such as the Command and Control Processor C2P and the Joint Tactical Information Distribution System JTIDS are quickly becoming commonplace on various platforms in the Navy This chapter will introduce you to some of the changes taking place and the basic features of some of the new systems After completing this chapter you should be able to Describe the various components of the AN USQ 125 Data Terminal Set Describe the operation of the AN USQ 125 in a typical Link 11
209. ic The purpose of those reviews is to refresh your memory in case you have not worked in the area for sometime After completing this chapter you should be able to Identify system equipment configurations and how they link together e Recognize various extremely low frequency through super high frequency naval equipment Compare a simplex relay system with a duplex relay system in microwave communications SHIPBOARD COMMUNICATIONS OVERVIEW Shipboard communications are now highly sophisticated Nearly all the communications requirements for a ship can be met with fewer more versatile pieces of equipment This versatility came about through improved equipment design and installation As communications equipment became more capable and complex the need for an orderly process of identifying equipment by designation became apparent The process that was developed identified equipment from the system level down to the part level The highest level designator system describes 2 1 Identify teletype equipment and portable and pack radio equipment Identify the Communications Link Interface Planning System pieces of equipment that work together for a specific function The lowest level designator part describes one piece like a resistor The following paragraphs describe the various levels in greater detail SYSTEM Recall from chapter 1 that a communications system is a collection of equipment used together to satisf
210. ich the following values 1 Greater than 90 percent 2 Greater than 100 percent 3 Greater than 95 percent but less than 100 percent 4 It must equal 100 percent A multi station POFA as considered successful when the computed receive error factor is less than what percentage 1 3 10 I9 a Np Which of the following buffers is acceptable to be received from an unrecognized station UNREC STA when a multi station POFA is running One buffer of 200 words One buffer of 230 words Two buffers of 200 words Two buffers of 230 words Hm CO DO Fe The heading PARITY STATUS OF CORRECT WORDS lists which of the following error conditions 1 Words determined to be correct by the DTS parity check and found in error by the computer parity check 2 Words determined to have an error and corrected by the DTS 3 Words determined to be correct by both the DTS and the computer parity checks 4 Words determined to be in error by the DTS parity check and found correct by the computer parity check 4 29 dl 4 925 41 334 04 The LMS 11 is designed to i555 perform which of the following EUNCE TONS 1 Isolate problems to the component level in the Link 11 system 2 Provide a history ort lvunk ll net performance 3 Provide a real time visual display of the Link 11 net operations 4 Provide the technician with a visual display of the Link 11 operation of one unit 1550 The LMS 11 is a complex s
211. ier 4 A hull number What is the duration of each time slot in a Link 16 message le 7812 9 msec 2 7 0125 usec em 1 8125 seconds 4 It varies according to the amount of data transmitted During The Transmission OF data exactly how often does Link 16 change frequency Every 13 usec Every 13 msec Daily When the frequency is excessively noisy Hm CO pL 3l Lhank l6 Ts contrigured for a stacked net At any one time what number of nets can a single terminal transmit and receive data 1 One 2 Two 3 Three FOOT A Link 16 data word is comprised of what number of data bits ue 390 Ze 760 TO ds 90 A Link 16 fixed format message is which of the following message types 1 V series 2 R series 3 M series 4 j series Which of the following message types are used for Link 160 voice communications Fixed format Free text Variable format Unformatted Hm CO DL Which of the following message types are used to exchange tactical data Fixed format Free text Variable format Unformatted H Textbook Assignment pal O22 cor 0 29 ASSIGNMENT Compared to Link 11 Link 16 is nodeless for which of the following reasons 1 Once the net is established all units must participate 2 Only one unit controls the net 3 Once the net is established operations can continue regardless of the participar on Of amy parti
212. increase and net efficiency to decrease The idea that the NCS must use dummy PUs for the link to 5 2 operate properly is not generally true It may be true only in infrequent isolated cases Studies have shown that in the old NTDS system CP 642 computer and the AN USQ 36 DTS a dummy PU entered between a live PU and own address was required for NCS data to be output at each NCS report opportunity Since the CP 642 computer and the AN USQ 36 DTS have virtually disappeared dummy PUs should not be used Myth Radio Silence Reduces Net Cycle Time The effect Radio Silence has on net cycle time depends on a number of factors As you saw in the last chapter if a PU does not respond to a call up in 15 frames the PU is interrogated again After another 15 frames if the PU still does not respond then NCS polls the next PU If the PU that goes to Radio Silence was sending reports that exceeded 38 frames then net cycle time would be reduced by the PU going to Radio Silence Effective net management would be to eliminate the PU number of the unit that has to go into Radio Silence until that unit is able to reenter the net As you can see there are several misconceptions on the proper way to manage and troubleshoot the Link 11 system In this chapter we concentrate on the tools available to the technician to aid in the isolation of link problems LINK 11 PROGRAMMED OPERATIONAL AND FUNCTIONAL APPRAISAL POFA Two types of POFAs are used in
213. information and how it is displayed These are NCS PU SIDEBAND and SUMMARIZE of the entries are displayed as part of the header of the Net Display screen The NCS PU and SIDEBAND fields are on the left side of the screen and the SUMMARIZE field is on the right side of the screen just below the date and time fields NCS 77 NET DISPLAY DATE 9 29 89 PU 0 RC FAST TIME 0 12 33 SIDEBAND USB LSB DIV SUMMARIZE T CYCLES 66 FRAME REL VAR PHASE ERR PU PWR SWR CNT THRU BER 605 DATA M SD _ 5 NCT 77 0 gt 34 75 100 5 0 6 1 0 3 0 7 0 2 gt 13 100 0 0 6 1 1 2 0 7 0 4 0 gt 34 52 0 0 0 6 1 1 2 0 7 1 6 0 gt 31 11 33 20 6 1 0 2 0 7 0 o el 2 9 100 0 o Q 5 0 0 0 i2 0 5 54 8 18 2 4 0 22 n w 0 0 8 2 5 7 4A TO 5 0 gt 23 15 20 0 23 6 1 2 3 0 70 16 gt 31 11 33 0 20 6 1 4 2 0 7 0 20 51 0 0 0 100 0 0 0 0 0 0 21 0 23 52 0 0 0 6 2 0 6 75 7 0 22 0 23 9 0 0 25 6 1 1 4 15 7 0 23 0 24 62 100 0 0 6 1 3 5 5 7 0 24 0 22 13 100 0 0 6 1 3 5 26 7 0 30 51 0 0 0 100 0 0 0 0 0 0 31 0 3 13 100 0 0 6 1 4 2 0 7 0 32 0 gt 34 14 100 0 0 6 1 2 3 0 70 36 51 0 0 100 0 0 0 0 0 41 0 gt 30 13 100 0 0 7 2 1 2 0 7 0 43 gt 33 41 100 0 y 3 1 2 0 7 1 XMT ADDRS 20 02 24 06 41 22 31 43 12 24 32 36 36 16 10 04 30 23 15 21 77 p
214. ink 4A uses which of the following frequency bands for data exchange HE only 24 Only 3 VHF only 4 Both UHF and VHF ee DT 6 In which of the following Link 4A modes of operation 15 an aircraft directed to a specific location to be at an optumum position xor dnm attack 1 Precision course direction 2 Automatic carrier landing system Ju Boe Craii control 4 Intercept vectoring In which of the following Link 4A modes of operation is used to maintain safe flight patterns and assigns priority for landing approach le Precision JOOUfsSe direction 2 Automatic carrier landing system 3o AIF trario Control 4 Intercept vectoring Which of the following Link 4A modes of operation is used for the remote guidance of bombers reconnaissance aircraft and drones 1 Precision course direction 2 Automatic carrier landing system o AIr control 4 Intercept vectoring In which of the following Link 4A modes of operation is used to land an aircraft on the flight deck of a carrier l Precision course direction 2 Automatic carrier landing system 2e ALL Pe 4 Intercept vectoring The CAINS aircraft alignment data loaded into the navigation computer of the aircraft consists of which of the following types of data 1 The latitude and longitude of the ship only 2 The ship s velocity only 3 The latitude longitude and ship s velocity
215. installed onboard aircraft carriers cruises destroyers and amphibious assault ships Two phases of shipboard installation designated Model 4 and Model 5 are planned Model 4 is being installed on ACDS and AEGIS platforms in conjunction with the installation of the Command and Control Processor C2P Model 4 does not implement any of the expanded data exchange capabilities of Link 16 Instead it supports existing Link 11 and Link 4A with its jam resistant increased capacity waveform Platforms with the Model 4 Link 16 system will retain their original 7 8 Link 11 and Link 4A systems and can use these systems by placing the C2P in bypass Model 4 is being installed on very few ships most of which will be upgraded to Model 5 therefore our discussion of Link 16 equipment will concern the Model 5 system Link 16 Model 5 The major components of the Link 16 system are the Tactical Data System TDS the C2P and the JTIDS terminal as shown in fieure 7 6 The TDS and C2P provide the JTIDS terminal with tactical data to be transmitted The Link 16 Model 5 fully implements all the capabilities of Link 16 For this implementation to take place major software changes must be made to the TDS and C2P programs Also the OJ 663 console replaces the current display x Link 4A lt Link 4A Messages Link 4 DTS Radio MODEL 5 Y uci Link 11 M Niit Messages Link 11 HF UHF VERSION 1 Crypto DTS MODEL 5 AC
216. ion 1s the difference between the maximum and the minimum Under ideal conditions the variation 1s zero The TADIL specification for maximum variation is 1 5 dB PHASE ERR M This is the mean or average phase error of the data tones The intelligenceis stored in the data tones by use of the phase differences that are odd multiples of 45 degrees If the phase difference of a data frame is 50 degrees when the expected difference is 45 degrees the error would be 5 degrees The phase errors for each tone are added up and after the specified number of cycles the sum for each tone is divided by the number of frames to obtain the mean phase error for each tone The mean phase error for all 15 tones is then summed and divided by 15 to obtain the value displayed PHASE ERROR SD This is the standard deviation of the phase error in all 15 tones RFE DS This is the radio frequency error or Doppler shift measured in Hertz If the Doppler correction was enabled during the LMS 11 initialization the value is color coded green If the Doppler correction is turned off this value is color coded cyan NCT This is the net cycle time as measured from phase reference frame to phase reference frame of the reporting unit Note that this measure of net cycle time is different from that used in other NCT calculations PU Display The PU display shows detailed information about the signal received from the specified PU The PU
217. ions centers located strategically throughout the world These SATCOM links are part of the Defense Satellite Communications System DSCS and Fleet Satellite Communications Satellite communications systems are very important to the worldwide military com munications network for two primary reasons First they continue to operate under conditions that cause problems for other methods of communication Second they provide reliable and secure com munications to previously inaccessible areas In many cases these communications requirements can only be satisfied by sophisticated satellite communications systems By satisfying such needs SATCOM makes a significant contribution to the improved reliability of naval communications ADVANTAGES OF SATELLITE COMMUNICATIONS Some of the unique advantages SATCOM has over conventional long distance communications are as follows SATCOM links are unaffected by the propagation problems associated with hf radio communications SATCOM links are free from the high attenuation problems of facilities that use wire or cable for routing communications SATCOM links span long distances The numerous repeater stations required for line of sight and troposcatter systems are not needed As you can see satellite links provide the required flexibility and reliability needed to support military operations In the following paragraphs we will look at SATCOM capacity reliability vulnerability
218. ipment is being tested The configuration in which the POFA was run determines some of the equipment being tested The POFA can be run in two configurations as shown in figure 5 1 In the full configuration the single station POFA will test the following areas e CDS computer I O channel recognition and acceptance interrupt Security device I O path Data terminal transmit and receive registers multiplex and demultiplex and transmit and receive sequence operations Switchboard integrity DYITS to radio and radio to DTS audio path Capability of the HF radio set to develop and accept sidebands both transmit and receive By studying the above list you can see that most normal link operations are tested during a single station POFA Certain functions however are not checked by running a single station POFA The DTS uses the transmit timing as the reference for the entire test therefore the receive timing circuitry is not checked Also certain other functions such as Doppler correction are not checked The printout generated at the end of a single station POFA lists interrupt status illegal interrupts parity and bit by bit word errors A single station POFA should always produce a totally error free printout However when a printout with errors is received the technician needs to be able to analyze the error package effectively The interrupts for example must occur in the following sequence
219. ircraft with this preassigned address will recognize the message and act on the message data Following the address is a five digit label that designates the type of data contained in the message The labels correspond to the modes of operation The last digit designates whether the message is an A both an A and a B type of message are required to transmit all the necessary data type In most modes to the aircraft The remaining data bit time slots contain the various control commands Transmitter Un key Signal The last time slot slot 70 is a 200 usec period allotted for transmitter turn off time and does not contain any data REPLY MESSAGE FORMAT Reply messages are received during the 18 msec receive cycle The reply message contains a total of 56 time slots and occupies a period of 11 2 msec This 11 2 msec reply must be received during the 18 msec receive cycle This allows for a maximum of 4 8 msec for transmission delay The reply message consists of a sync preamble 42 data bit time slots and a guard interval as shown in The sync preamble is identical to the control message sync preamble The information in the 42 data time slots is divided into groups of digits that identify the source and type of message and the message data The last time slot is the guard interval and it allows for transmitter turn off time REPLY MESSAGE Figure 6 3 The Link 4A reply message format INPUT fa 1
220. is the normal position of this switch DATA RATE SWITCH Selects the data rate When the switch is in the DUAL 1200 position the data converter can transmit that the data converter uses and receive two unrelated streams of data at 1200 bps In the 1200 and 2400 positions the data converter transmits and receives a single data stream at 1200 and 2400 bps respectively When the switch is in the TADIL A position the data rate is controlled by the DATA RATE switch on the TADIL control panel The TADIL A position is the normal position for Link 11 SYNC MODE SWITCH The SYNC MODE switch selects the mode of synchronization used by the DTS receive circuitry and is used in conjunction with the TIMING STORED CORRECTED switch on the TADIL control panel The normal operating position for the SYNC MODE switch is in the FAST CONT position When the switch is in the FAST CONT position both the fast and continuous synchronization circuits of the DTS are selected Synchronization is initially obtained during the five frame preamble and maintained continuously during the data portion of the transmission The TIMING switch on the TADIL A control panel must be in the CORRECTED position When the FAST position 15 selected synchronization is only during the five frame preamble If the CONT position of this switch is selected only the continuous synchronization circuits are selected Synchronization is obtained only during the data
221. issile operations Surface ships and submarines operate in a TADIXS receive only mode OTH T data from the fleet destined for shore or other fleet users 15 sent by the afloat Tactical Data Processors TDPs through the TADIXS ON 143 V 6 USQ to the OTCIXS ON 143 V 6 USQ for transmission over the OTCIXS satellite A TADIXS surface ship installation is shown in figure Each OTCIXS equipped surface ship or submarine can enter both out going teletype and TDP traffic simultaneously Rf Transmission Link Control The TADIXS satellite link network operates in a half duplex manner at a data rate of 2400 bps in a permanently assigned time slot of a uhf DAMA channel Control of message traffic transmission is V SSS a ae ATCA IRANOUFIVER TAC CONST Ne AN WSC 3 V DATA PROCESSOR BT WV LV VVI _ NOTE 1 ce i MEM i TADIXS DAMA SATELLITE LINK MULTIPLEXER CONTROL CONTROLLER TD t271B U INDICATOR K 94 0n 143 V 6 USQ 11430 USQ CONTROL MONITOR i Ili i GROUP i H 1 454 5 I YVA i AD I LI pip i OK455 WSC i i AN USQ 64 V 8_ ___________________________ 3 tL g q p 2 2 T i i
222. k Operating Systems 6 14 Open System Interconnection OSI Reference Model R Receivers AM superheterodyne 1 9 characteristics 1 8 FM superheterodyne 1 9 functions 1 7 microwave 2 12 ssb 1 10 Recognizing Link 11 Problems Remote control unit 7 4 Satellites Shipboard Gridlock System 4 3 Single station POFA 5 3 Single tone waveform link 7 2 STARLAN T Tempest black criteria red criteria 2 24 Transmitters microwave 2 10 2 11 AM 1 16 CWI 1 5 FM 1 6 fundamentals 1 4 portable and pack 2 24 ssb 1 6 INDEX 3 Assignment Questions Information The text pages that you are to study are orovided at the beginning of the assignment questions Textbook Assignment IA ped 15955 1 364 ASSIGNMENT 1 Fundamentals chapter 1 Systems Equipment Configurations through 29574 What type of equipment is used Ly to coordinate the activities of fleet units by linking them with each other and shore stations Radio 2 Weather 3 Radar 4 Navigation 1 94 Radio is the transmission and reception of electronic impulses or signals through space by means of what type of waves 1 Pulsed 2 Phased qe 3 Electromagnetic 4 Electrostatic Who is ultimately responsible for safety ls QO Z MC Su CPO LAO 4 Everyone What are the basic requirements of a communications system 1 Transmitter and receiver 2 Teletype and converter 3 Trans
223. kstations is another name for the PCs used on a network The PCs can be of the same brand such as Zenith or they can be a combination of different brands such as IBM Zenith Compaq along with other PC compatible computers clones Each PC can be configured differently Some might have their own hard disk drives others might have expanded memory Still others might NOT even have diskette drives or printer ports of their own Instead these less expensive workstations use the storage and printing resources available through the network Even though a PC may be part of a LAN system you can use it independently as a stand alone PC at any time or you can use it as part of the LAN THE OPEN SYSTEM INTERCONNECTION OSI REFERENCE MODEL Over the past few years a number of network standards or protocols rules to live by have been developed by the International Standards Organization ISO to provide some level of uniformity among computer manufacturers and network vendors ISO is one of several governing organizations in this field that has developed such protocols ISO has defined a five level seven layer architecture These seven layers of standards shown in figure 8 1 define a generalized architecture called the Reference Model of Open Systems Interconnection It is also known as the OSI reference model or OSI model The primary purpose of the OSI model is to provide a basis for coordinating the development of standards that relate to
224. l cease transmission and wait until the line is clear 2 The workstation will continue to transmit data 3 The network server will assign the next open time to the workstation that suffered the collision 4 No action is taken the data Te LOSE In a LAN using a token ring topology the interface and protocols are defined by which of the following IEEE standards ly IEEE 802 2 LEERE 902 23 3 8024 4 IEEE 802 5 Which of the following LAN systems uses a token ring topology and has a data throughput of 4 Mbits and 16 Mbits per second 1 EtherNet 2 STARLAN 3 ARCnet 4 IBM Token Ring 36 A Control Kernel Network interfaces C File systems D File extensions Figure 6B IN ANSWERING QUESTIONS 6 46 THROUGH 0 49 SELECT FROM FIGURE 6B THE NETWORK OPERATING SYSTEM COMPONENT THAT PERFORMS THE FUNCTION DESCRIBED EN THE QUESTION NOF TEMS LN THE LIST ARE USED oed Provides low level subnet protocols and translation or bridging hardware drivers with the network operating system Co ES Pp Controls data organization storage and retrieval on the various storage systems available to the network IONE OU The main subsystem of the network operating software OU D Which of the following network operating systems if any is designed for very few users and light usage Full featured Low cost Zero slo
225. large demands upon the rf spectrum These demands include military and civilian applications such as communications lo cation and ranging identification standard time in dustrial medical and other scientific uses The military has modified the frequency spectrum for its use as shown n table l 1 A few general charac teristics are described in the following paragraphs The extremely low frequency elf very low frequency and low frequency If bands require high power and long antennas for efficient transmis sion antenna length varies inversely with the fre quency Transmission of these frequencies is normally limited to shore stations The commercial broadcast band extends from about 550 kHz to 1700 kHz This limits naval use to the Table 1 1 Frequency Bands AM ANN E Hz extremely high frequency 3 30 GHz super high frequency 300 MHz 3 GHz ultra high frequency 30 300 MHz very high frequency 3 30 MHz high frequency ____ _ medium frequency 30 300 kHz low frequency 3 30 kHz very low frequency ANN TY Z extremely low frequency upper and lower ends of the medium frequency mf communications repeater operation navigation am band phibious and special operations short range line of T sight LOS communications and satellite communi Long range shipboard communications were con ducted exclusively in the high frequen
226. ld be able to e Describe the Describe the Describe the Describe the Describe the Describe the e Describe the modes composition of a typical Link 11 system operation of the Link 11 transmission and receive cycles six operating modes of the Link 11 system function of the Link 11 encryption security device audio tones generated by the Link 11 Data Terminal Set word formats used to transmit Link 11 tactical data message formats used in the various Link 11 operating e Describe the Operation of the Link 11 Data Terminal Set LINK 11 FUNDAMENTALS To monitor the operation of and perform maintenance on the Link 11 system you must understand how the different pieces of equipment interact with each other Let s take a look at a basic Link 11 system LINK 11 SYSTEM OVERVIEW A typical shipboard Link 11 communications system and consists of the following components the CDS digital computer a cryptographic device the Link 11 data terminal set the communications switchboard and the HF or UHF radio set transceivers transmitter receiver an CDS Nr COMPUTER SYSTEM DATA TERMINAL ur or mii FREQUENCY STANDARD antenna coupler and an antenna The data terminal set is the center of the Link 11 system and is covered in detail later in this chapter The communications switchboard is used to select the desired HF or UHF transceiver external frequency standard is also part of ma
227. lexed audio frequency tones Le gt gt Zig d 3 4 30 Bits 4 and 9 of a 230 Dbrrt data word are carried by which of the following audio tone frequencies DO CEDE Zu JUSS He 3e 12609 HZ 1705 Hz 15 3241 3 49 35 905 What is the basic unit of the transmission le BIC 2 Tone 3 Frame 4 Doppler In a single frame the DTS can tolerate what maximum phase shift error without generating an error code 44 degrees only 44 degrees only 44 degrees 135 degrees HA CO DO LE A phase shift error of 105 degrees in any one of the data tones will cause a single bit to be erroneous 1 True 2 False Which of the following Link 1l signals allows the receiving unit to correct errors caused by the relative motion between the sending and receiving nits 1 Sync tone 2 Doppler tone 3 Data carrying tones 4 Motion correct tone During the preamble the 2015 Hz tone sets Which of The following references 1 Frame timing when the DTS is in corrected timing 2 Signal power levels when the DTS 15 in corrected timing 3 Frame timing when the DTS is in stored timing 4 Signal power levels when the DIS se In stored Taming During the reception of the data segment of a Link 11 message the 605 Hz Doppler tone should be at which of the following power levels be 2 SO dB oa SUD SE 4 0 dB 35923 m k 5200 When the DTS is in th
228. lly limited to radios modems crypto devices input output data terminals and packet controllers normally used to establish these radio links 2 29 The CLIPS program is designed for use with IBM PC or compatible computers using MS DOS It is designed to provide solutions to equipment planning and link configuration problems by considering all the factors involved and automatically determining the best system to be used by each participant in the communications link The CLIPS program in corporates the knowledge of experienced com munications personnel equipment specifications circuit planning rules and equipment inventories in a way that makes communications planning straight forward easy and objective 3 SATELLITE COMMUNICATIONS INTRODUCTION In the past the Navy relied upon hf communications as its primacy method of sending messages With the overcrowding of the hf spectrum the need for new and advanced long range communications became apparent Satellite communications SATCOM systems have shown they can provide survivable reliable high capacity secure and cost effective telecommunications for the military In this chapter you will be introduced to satellite communications fundamentals fleet SATCOM sub systems shore terminals current and future satellites and some specific SATCOM equipment and racks SATCOM is a natural outgrowth of modern technology and the continuing demand for greater ca
229. logy Although the technology used in the different models of the Link 11 DTS may be vastly different all of them perform the same function Normally the DTS operates in the half duplex mode meaning it can either receive or transmit data but it cannot do both at the same time An exception is during system test when the DTS operates in full duplex mode and can simultaneously send and receive data DATA TERMINAL SET FUNCTIONS The DTS also performs the following functions Error detection and correction Audio signal generation Link 11 protocol and interface control Error Detection and Correction EDAC The DTS receives data from the CDS computer in the form of 24 bit binary data words The 24 data bits Table 4 1 DTS Parity Bit Status Codes MODE ERROR STATUS Detect and Label BIT POSITION 25 24 No errors detected 0 0 Error s detected no correction attempted 1 0 Detect and Correct No errors detected dS Parity errors detected 0 1 Odd error s detected correction attempted Even errors detected no correction attempted 0 are expanded to 30 bits by adding six bits for error detection and correction EDAC These six bits are also called hamming bits The value of these bits are based on parity checks of specific combinations of the 24 bit data word During the receive cycle the six EDAC or hamming bits are examined for errors The
230. long a common data bus For this reason it is difficult to maintain network security 6 8 mimi 800MB rem D e D eo Lui HARD DISK CAN BE SHARED ALL USERS FILE BASIS 38NP0187 Figure 8 3 A star network topology Tha STAR NETWORK In a star network each component is connected directly to the central computer or network server as shown in figure 8 3 Only one cable is required from the central computer to each PC s network interface card to tie that workstation to the LAN The star is one of the earliest types of network topologies It uses the same approach to sending and receiving messages as our phone system Just as a telephone call from one person to another is handled by a central switching station all messages must go through the central computer or network server that controls the flow of data New workstations can be easily added to the network without interrupting other nodes This is one of the advantages of the star topology Another advantage of star topology is that the network administrator can give selected nodes a higher priority status than others The central computer looks for signals from these higher priority workstations before recognizing other nodes The star topology also permits centralized diagnostics troubleshooting of all functions It can do this because all messages must first go through the central computer This can prove invaluable in making sure that net
231. lows reports of areas that are limited in size and are circles ellipses squares or rectangles Link 11 does not have the capability to report lines GEODETIC POSITIONING The Link 16 messages use the geodetic coordinate system to report positions This system uses latitude longitude and altitude to report positions anywhere in the world Link 11 uses the Cartesian coordinate system which requires the reporting unit to be within a certain range when reporting positions RELATIVE NAVIGATION The Relative Navigation RELNAV function of the Link 16 system 15 automatically started by every Link 16 participant and is constantly operating The RELNAV function determines the distance between reporting units by measuring the arrival times of transmissions and correlating them with the reported position of the unit This information is required by each terminal in the network to maintain synchronization The RELNAV data can also improve a unit s positional accuracy Also if two or more units have accurate geodetic positions RELNAV can provide all other units with accurate geodetic positions ELECTRONIC WARFARE The Link 16 system increases the types and amount of electronic warfare information that is exchanged between units LAND POINTS AND TRACKS The Link 16 system adds Land as a track category and allows the reporting of land objects such as buildings or vehicles EQUIPMENT CONFIGURATION Currently Link 16 will be
232. ls it is an indication of the degree to which a circuit deviates from the ideal a noise figure of 0 decibels is ideal Selectivity Selectivity is the ability of a receiver to distinguish between a signal at the desired frequency and signals at adjacent frequencies The better the receiver s ability to exclude unwanted signals the better its selectivity The degree of selectivity is determined by the sharp ness of resonance to which the frequency determining components bandpass filters have been engineered oe E A bat sl NPER Home URE AMPLIFIER DEI Reels bes M SPEAKER N Ot M pue LOCAL OSCILLATOR EOE ENVELOPES _ Ni ND gt we RF CARRIER m AMPLIF IF CARRIER CARRIE T OSCILLATOR WAVE f Nh HP AA WY WW AUDIO AMPLIFIED COMPONET AUDIO COMPONET AMPLIFIED IF CARRIER ETVv30007 Figure 1 7 superheterodyne receiver and waveforms and tuned Measurement of selectivity is usually done by taking a series of sensitivity readings in which the input signal is stepped along a band of frequencies above and below resonance of the receiver s circuits As the frequency to which the receiver is tuned is ap proached the input level required to maintain a given output will fall As the tuned frequency is passed the input level will rise Input levels are then plotted against frequency The steepness of the curve
233. m my ji a EXE vier 0 n ity MEX EM v mt rta arte bmg PER ih Figure 3 33 Data Terminal Set AN USQ 69 V Signal Data Recorder Reproducer RD 397 V U The RD 397 V U _figure 3 34 is used in baseband equipment installations with CUDIXS NAVMACS and TACINTEL ship and shore The V 3 version is used at SSIXS shore locations This tape perforator reader can punch tape at 63 3 characters per second and read tape at up to 300 characters per second The equipment is self contained that is complete with control logic buffering and power supplies Navy Standard Teleprinter AN UGC 143 V The Navy Standard Teleprinter NST is the standard teleprinter terminal set for surface platforms The NST is used for netted circuits and for broadcast ship to shore and ship to ship communications circuits The various configurations of the NST provide for information preparation editing printing and receiving of serial data and buffering and storage of information An AN UGC 143A V 4 NST is shown in figure 3 35 ETV30072 Figure 3 34 Signal Data Recorder Reproducer RD 397 VVU ETV30073 Figure 3 35 NST AN UGC 143 V 3 32 Audio Digital Converter CV 3333 U The Audio Digital Converter CV 3333 U is called a vocoder or voice digitizer This unit is a solid state all digital speech processor providing
234. maging and fiber optics INSTRUCTIONS FOR TAKING THE COURSE ASSIGNMENTS The text pages that you are to study are listed at the beginning of each assignment Study these pages carefully before attempting to answer the questions Pay close attention to tables and illustrations and read the learning objectives The learning objectives state what you should be able to do after studying the material Answering the questions correctly helps you accomplish the objectives SELECTING YOUR ANSWERS Read each question carefully then select the BEST answer You may refer freely to the text The answers must be the result of your own work and decisions You are prohibited from referring to or copying the answers of others and from giving answers to anyone else taking the course SUBMITTING YOUR ASSIGNMENTS To have your assignments graded you must be enrolled in the course with the Nonresident Training Course Administration Branch at the Naval Education and Training Professional Development and Technology Center NETPDTC Following enrollment there are two ways of having your assignments graded 1 use the Internet to submit your assignments as you complete them or 2 send all the assignments at one time by mail to NETPDTC Grading on the Internet Advantages to Internet grading are e you may submit your answers as soon as you complete an assignment and e you get your results faster usually by the next working day approximat
235. me visual display of the Link 11 network while it is operating The LMS 11 is capable of measuring and displaying link signal data for the network as a whole as well as for individual units It can be used for periodic equipment checks or for continuous monitoring to determine the condition of all members of the net LMS 11 SYSTEM CONFIGURATION The LMS 11 consists of three groups equipment a data processing group DPG a control display group CDG and an accessory group AG The LMS 11 is shown in figure 5 3 The LMS 11 is designed to be portable and the equipment is installed in three carrying cases The equipment cases that house the electronic units of the DPG and CDG provide isolation from shock and vibration The CDG is designed to be mounted on the DPG cases Four latches fasten the two units together and provide a desk height self contained workstation The system printer which is part of the accessory group is mounted on the top of the CDG equipment case When the LMS 11 15 installed the accessory group case provides storage for the DPG and CDG equipment case covers The LMS 11 is normally located near the data terminal set but it may be installed anywhere near a 600 ohm Link 11 audio signal Data Processing Group the LMS 11 to receive sample and process Link 11 audio signals is contained in the data processing group The DPG also provides power control and distribution to the CDG and accessories The DPG co
236. message to see if it matches its own address Bus topologies allow individual nodes to be out of service or to be moved to new locations without disrupting service to the remaining nodes Because of the way linear bus cabling is laid out this type of network is simple The bus topology is very reliable because if any node on the bus network fails the bus itself is NOT affected and the remaining nodes can continue to operate without interruption Many of the low cost LANs use a bus topology and twisted pair wire cabling NETWORK SERVER PC 3 PC 5 THE BUS OR DATA HIGHWAY i lt lt lt lt lt lt DIRECTION OF DATA FLOW 38NP0186 Figure 8 2 A bus network topology A disadvantage of the bus topology is that generally there must be a minimum distance between workstations to avoid signal interference Another disadvantage is that the nodes must conpete with each other for the use of the bus Simultaneous transmissions by more than one node are NOT permitted This problem however can be solved by using one of several types of systems designed to control access to the bus They are collision detection collision avoidance and token passing which we will cover shortly Also there is no easy way for the network administrator to run diagnostics on the entire network The bus network can be easily compromised by an unauthorized user since all messages are sent a
237. mitter and handset 4 Receiver and handset je AN UCC 1 AN URA 17 and 2460 are examples of what type of shipboard equipment le ano lig 2 Auxillary 3 Special 4 Terminal uec For efficient transmission which of the following frequency bands require s high power and long antennas 1 ELF only 2 VLF only S dE OnLy Z BGR VLE and LE pages 1 1 through 1 15 and chapter 2 pages 2 1 Which of the following frequency bands has limited naval use JL HE 2 MF Ou 4 VHE What does the abbreviation los commonly mean Loss of signal Line of sight losses gh Line of signal HS GO The super high frequency band is used extensively in what of communications 1 Teletype 4 Repeater 3 Microwave 4 Computer Ihe emission class of an rf transmitter is based on what characteristic 1 Modulation 2 Power 2 5ensrtbovlty 4 Frequency An FM signal should remain constant in a what characteristic and change only in b what characteristic a Frequency amplitude 2 a Frequency b modulation 24 a Amplitude b frequency 4 a Amplitude b modulation What type of modulation is especially suited for use in time division multiplexing 1 Amplitude 4 Frequency 3 Phase 4 Pulse pL 15165 For modern communication needs CW is not a preferred method Why is this true CW is slow CW is complicated 15 expensive CW is noisy Hm CO N
238. mmunications Myth Changing Frequency Always Solves Net Problems Here again is a myth that has some basis of fact Changing frequency is a time consuming process When all the procedures are not carefully followed then changing the frequency induces additional problems into the net This myth developed because improperly set switch positions and patch panel configurations were often set to the proper position during the frequency changing process When the problem is connectivity on the current frequency the proper action is to find a better frequency Myth More Power Improves Link Performance This is a myth On the transmit side the idea behind the myth 15 that keeping the link HF transmitter tuned to maximum output power will result in maximum area coverage In fact constantly outputting maximum power can lead to serious RFI EMI problems on the ship doing so and will not significantly increase the signal propagation range The idea behind the myth on the receive side is that by keeping the HF receiver audio output control maximized receive quality improves In fact maximizing the audio output saturates most data terminal sets Saturation generally occurs in the DTS at around 3 dBm Signal inputs above this level actually increase receive data errors Myth Dummy PUs Improve Link Quality A dummy PU is an address insert into the polling sequence by the NCS for which there is no live unit Dummy PUs cause the net cycle time to
239. munication with all units NCS transmits Net Synchronization Net Sync If the NCS is using corrected timing normal mode the Net Sync verifies the communications path between NCS and all picket units If a picket unit cannot receive Net Sync it cannot participate in the net Net Test should follow Net Sync Net Test is used to confirm connectivity between the Link 11 units Units having difficulty in receiving Net Sync or Net Test should report to NCS that they are not able to participate in the net and then begin corrective action When Net Test is completed all picket stations report their status to NCS Then NCS directs all PUs to switch to the Roll Call mode and initiate link operations Net Synchronization and Net Test are used in the initialization of the net The normal mode of operation is Roll Call The above scenario has introduced you to several new terms and modes of operation These are explained in detail in the following paragraphs The following are the six modes of Link 11 operation Net Synchronization Net Test Roll Call Broadcast Short Broadcast Radio Silence Net Synchronization The Net Sync mode of operation is used to establish a uniform time base from which all net data communications normally initiate The Net Sync mode is usually initiated when establishing a link net after all operator entries have been properly completed The Net Sync transmission is manually started by the op
240. muth converter RAM random access memory RC Roll Call RDDS radar data distribution switchboard RELNAV relative navigation RF radio frequency RGB red blue green ROM read only memory ROM BIOS ready only memory basic input output system R SERIES MESSAGES Link 4A messages from the controlled aircraft that are sent in response to a control message SAC sonar azimuth converter SCG sensor converter group SDDS sensor data distribution switchboard SG symbol generator SRAC synchro radar azimuth converter SVGA super video graphics array TDM tactical DITEG module TDS tactical data system TFT thin film transistor TMG test message generator TN track number TQ track quality TSLO third salvo lock out AI 3 TTL transistor transistor logic TVC television converter group TVSC television scan converter UHF ultra high frequency USB upper side band V C word velocity category word VDT video display terminal VFK panel variable function key panel VGA video graphics array V SERIES MESSAGES Link 4A control messages sent from the controlling station to the controlled aircraft VSS video signals simulator XGA extended graphics array APPENDIX II REFERENCES USED TO DEVELOP THE TRAMAN NOTE Although the following references were current when this TRAMAN was published their continued
241. n for Link 11 messages to be transmitted over Link 11 and Link 16 The C2P computer stores the data in a central database called the normalized data base and then formats the data in the proper message format for the link system s being used Messages received by the various data links are processed for errors by the C2P computer and sent to the proper destination Received messages can also be reformatted for retransmission on a different link A Link 11 or Link AA message received by a C2P platform can be reformatted into a Link 16 message and retransmitted on Link 16 SYSTEM CONFIGURATION The hardware block diagram of the equipment used in the C2P system is shown in figure 7 11 The AN UYK 43 V is a general purpose large scale tactical computer used to store and execute the C2P software The C2P configuration of the AN UYK 43 consists of the following major modules Two central processor units Two input output controllers and adapters Six expanded time volatile memory units One embedded memory subsystem EMS with two embedded mass memory storage devices EMMSD A major change in the configuration of the AN UYK 43A V is the EMS and its associated EMMSDs The EMS consists of two 383 megabyte AN UYK 43 38NP0182 Figure 7 11 The system hardware configuration hard drives installed in the AN UYK 43 V cabinet Even though these disk drives are internally installed in
242. n phase shift in respect to the preceding frame the phase reference frame provides the reference for the first frame of data Each succeeding frame becomes the phase reference for the following frame 2915 Hz The PHASE REFERENCE frame transmits all 16 tones at normal power Ase HH Beets PREAMBLE Figure 4 6 The phase reference frame added to the preamble with normal data tone levels Information Segment The information segment of the Link 11 message is composed of control code frames and message data frames Control code frames consist of a start code a stop code and an address code Each control code is two frames in length and performs a specific function Control codes are not sent to the CDS computer PHASE REFERENCE Figure 4 7 The start code added to the Link 11 transmission START CODE The start code is a two frame code that follows the phase reference frame as shown in figure 4 7 When sensed by the DTS the start code 4 8 causes the DTS to send the Prepare to Receive Data interrupt to the CDS computer MESSAGE DATA FRAMES Message data frames contain the tactical data being disseminated and follow the start code as shown in fieure 4 8 The number of message data frames depends on the amount of tactical information the unit transmits The 24 bits of data contained in each frame 15 sent to the CDS computer PHASE REFERENCE FRAME 7 7 uw ad MESS
243. nation Baud By definition the word baud is a unit of modulation rate To find the modulation rate of a signal in bauds divide 1 by the time interval of the shortest unit in the signal For example 22 milliseconds 022 see 1s the time interval of the shortest unit 1n the five unit code at 60 wpm To find the number of bauds equal to 60 wpm divide 1 by 022 Rounding off the results provides the figure 45 5 which is the baud equivalent of 60 wpm You can see that increasing the wpm means the unit time interval has decreased The most common baudot data speeds range from 45 45 to 100 bauds or about 60 to 133 wpm Higher speeds are obtained using the American National Standard Code for Information Exchange This is a seven unit digital code used for the transmission of teleprinter information ASCII is used primarily with computer systems but it is also used in some teletypewriter applications The Defense Communications System standard speed for teletype operation is 100 wpm or 75 baud TIME Figure 2 14 Mark and space signals in the teletypewriter character R 2 16 Words per minute 18 used only when speaking in general terms about an approximation of speed At a speed of 100 wpm 100 five letter words with a space between them can be transmitted in a 60 second period But you can also get this wpm rate by varying the modulation rate or the length of individual characters Because of this the baud method
244. nd can multiplex up to 56 baseband circuits An OK 481 V 2 FSC is shown ir figure 3 42 CHAPTER 4 THE LINK 11 SYSTEM INTRODUCTION Tactical data links are usually limited to a specific area of operation and are used for command and control of specific forces Link 11 15 the U S Navy shipboard version of Tactical Data Information Link A TADIL A The Link 11 system is used to provide high speed computer to computer exchange of digital tactical information among ships aircraft and shore installations as shown in figure 4 1 AIRCRAFT ASW LINK 11 CDS m CARRIER CDS INTERCEPTOR STRIK INTERCEPTOR STRIKE LINK 4A LINK 11 HOSTILE LINK 11 LINK 11 CDS HOSTILE 4 INTECEPTOR STRIKE t CQ 38NP0144 Figure 4 1 Tactical digital information links Link 11 data communications can operate with either high frequency HF or ultra high frequency UHF radios In the HF band Link 11 provides gapless omnidirectional coverage of up to 300 nautical miles from the transmitting site In the band the Link 11 system is capable of line of sight omnidirectional coverage approximately 25 nautical miles between ships and 150 nautical miles for ship to air links To understand the operation of the Link 11 system fully you must be able to identify the hardware components that compose it and the functions they perform 4 1 After completing this chapter you shou
245. nd reperforator are used for preparing tapes that can be stored for future transmission through the transmitter distributor The AN UGC 143A V is also known as the Navy Standard Teleprinter NST and has the following characteristics e Fully automated Accepts Baudot code or ASCII e Bulk storage unit contains tape drives similar to those found in the AN USH 26 e Can be configured to interface with Navy standard personal computers e Fully compatible with current crypto devices Capable of supporting paper tape operations 2 20 Patch Panels Tty panels SB 1203 UG and SB 1210 UGQ are used for interconnection and transfer of shipboard tty equipment The SB 1203 UG is a general use panel and the SB 1210 UGQ is intended for use with crypto In addition tty panels furnish a central point for connecting the dc supply into the teletypewriter circuits So one source of supply can be used for all the circuits passing through a particular panel One procedural note Anyone patching or unpatching circuits from a tty panel must be sure to pull the plug from the looping jack before removing the other plug from the set machine jack Pulling the set jack first interrupts all tty message traffic on that channel IT ALSO PRODUCES A DANGEROUS DC VOLTAGE ON THE EXPOSED PLUG Cryptographic Equipment Cryptographic equipment is used to encode and decode messages that require security handling To do this the crypto equipment must b
246. nd the LMS 11 display are covered in the next few paragraphs Figure 5 14 shows an example of how a PU not responding to call ups would appear on the LMS 11 operating in the Link Monitor mode When a PU does not respond to a call up the reason may be that the incorrect PU number was entered at the NCS or at the DTS of the unit It can also be caused by a poor receiver at the PU causing the PU to not receive its call up A third problem could be a weak transmitter at the PU causing the NCS to not receive the response and therefore repelling the PU 38NP0207 Figure 5 14 A PU not responding to NCS call up Figure 5 15 shows the display that appears when a PU is responding to NCS call ups but the report contains no data Causes of this problem could be the KG 40 has an alarm the CDS program is down or the problem is in the CDS computer to DTS patching 16 44 8S8 _ E l 38NP020 Figure 5 15 A PU responding with no data When NCS fails to receive a stop code from a PU it causes a stoppage of the net as shown inl figure If this condition occurs repeatedly and can be traced to a single PU the NCS should delete the PU until the stop code problem in the DTS 15 corrected 54 52 P 9 a 38NP0209 52 Figure 5 16 A net stoppage caused by NCS not receiving a stop code Figure 5 17 shows several PUs not responding to call ups S
247. nderstand and be familiar with both RED and BLACK designated systems and equipment The RED and BLACK designations are explained in the following paragraphs RED CRITERIA The RED designation applies to all crypto equipment subscriber terminal equipment and interconnecting conductors involved in processing classified plain language information It also applies 1 ANTENNA MULTICOUPLER TRANSCEIVER RECEIVER TRANSMITTER TRANSFER TRANSFER SWITCHBOARD SWITCHBOARD en TERMINAL SET COMMUNICATION PATCHING PANEL 5 XMTR TTY EY CONTROL UNIT Figure 2 20 Half duplex AFTS teletype system ETV30032 to primary power circuits dc circuits control wiring and ground conductors serving cryptographic equipment and subscriber terminal equipment that are designated RED The RED designation also applies to junction boxes distribution frames terminal boxes conduit ducts cable racks and hangers patching and switching panels cabinets power distribution panels both ac and dc and other ancillary equipment serving the conductors and equipment mentioned above Primary Red Any conductor intended to carry classified plain language terminating in RED equipment or the RED side of crypto equipment is designated PRIMARY RED Secondary Red Any conductor other than PRIMARY RED that connects to RED equipment the RED side of crypto equipment or the RED side of isolation devices and
248. ne is shifted with respect to the previous frame The amount of this phase change or phase difference determines the value of a two bit number Two data bits yield the following four possible combinations 00 01 10 and 11 Each combination is associated with a phase difference of one of four values 45 degrees 135 degrees 225 degrees or 315 degrees from the previous position Table 4 2 Tone Library Manann Nanana h n ue Trannancy H DNeccrintio 1 1NUIIIDUCI ELCYUCHMLY UEL eaves soo 1 QUI a nA Nata A anA 1 2 9353 Data U and 1 A 14 3 1045 Data 2 and 3 4 1155 Data 4 and 5 5 1265 Data 6 7 Pa 1274 Q and Q 12 2 17 aliu 7 4 Mata 13 11 1462 pata 1U and it 8 1595 Data 12 and 13 9 1705 Data 14 and 15 10 1Q15 Data 16 and 17 LU A 4064 11 1925 Data 18 and 19 1A ANAL IN ate nA any 31 12 Z033 Vata ZU ana 21 13 2145 Data 22 and 23 14 2255 Data 24 and 25 15 2365 Data 26 and 27 oad 17 NATE Nyata QunrX 20 and 30 10 721 Lata DO 7 ARE There is no bit location associated with the
249. nition Any errors detected will cause the LOOPBACK FAIL indicator to be displayed LOOPBACK TEST 4 Loopback test 4 is used to check the operation of the computer interface the crypto device and the data terminal interface circuitry When this test 1s selected the audio circuits are disabled and the data from the computer is sent to the memory in the data terminal Upon receipt of the end of transmit signal the data in memory is sent back to the computer for evaluation DTS FAULT ISOLATION TESTS The DTS fault isolation tests are built in tests BIT designed to test and isolate a fault to a particular circuit board REMOTE CONTROL UNIT The C 12428 USQ 125 remote control unit CU enables the operator to control the data terminal from a remote location The control unit used with the data terminal forms the data terminal set DTS The control unit is used by the operator to enter operating parameters start and stop link operations and change figure 7 4 link modes One model shown 1 consists of a 486DX2 66 MHz AT compatible personal computer in a rugged chassis for shipboard operation The keyboard trackball unit is in a special detachable enclosure that also serves as a front cover for the CU A 386 or better personal computer maybe substituted for the control unit when loaded with the proper software and connected to the data terminal FRONT PANEL ASSEMBLY TN i KEYBOARD TR CKBALL 2687 l
250. not just a vhf transmitter or receiver What is the name given to a piece of equipment that performs both Ino 5505 1 Transducer 2 Multiplexer 3 Retransmitted 4 Transceiver During UHF secure voice transmission the operator uses a secure voice remote phone unit What is the common term Lor CRIS Unit RES RPU SVP SPU H w Fe which of the following combinations of radio relay systems provides a one way communications and b two way communications Simplex b multiplex ve a Duplex b multiplex Du a Simplex b duplex 4 a Duplex 0 simplex What term is normally used for microwave transmitter input signal 1 Baseband signal 2 Emphasis signal 3 Insertion signal 4 Linear signal In a microwave transmitter the linearize couples a portion of the output power back to the klysbron This allows modulation densities as high as 1200 channels and compensates for what klystron deficiency 1 Nonlinearity 2 OsociLlatrons 3 Overheating 4 Selectivity In a typical microwave receiver what is the standard intermediate frequency 1 40 MHz 2 50 MHz 35 60 MHz 4 70 MHz Which of the following methods are usually used for microwave communications Los and troposcatter Los and satcom Troposcatter and satcom Troposcatter and shortwave Hm CO BRO pm 1237 15 252 By which of the following methods can you increase the maximum number of intelligible
251. nsists of the following equipment The equipment required The control processing unit The audio interface unit The dual 3 5 inch floppy disk drive unit e The power control unit CONTROL PROCESSING UNIT The control processing unit consists of the HP9920U 5 7 PART OF ACCESSORY PRINTER CONTROL DISPLAY GROUP KEYBOARD amp DISK DRIVE U AUDIO INTERFACE NIT DATA PROCESSING CONTROL UNIT CONTROL PROCESSING ed I J Figure 5 3 The LMS 11 computer with an additional 2 MB of ram and associated circuit card assemblies CCA These circuit cards include the following Color output CCA Composite Video CCA Data communications interface interface bus HP IB Analog to digital converter assembly Fast Fourier Transform FFT processor The color output CCA and the composite video CCA provide the necessary signals to drive the color monitor The data communications interface provides an RS 232C asynchronous serial interface for the color printer The HPIB is used to interface the system keyboard and the dual disk drives to the computer gt c AJ o 2 Oo Q j A r ST R Ne l7 Q Ww E R T Y U PRINT f FREEZ ST AT A A Y ae V eee V que eB gem ME A 5
252. ny Link 11 systems Additionally the Shipboard Gridlock System SGS is installed on many ships On SGS equipped ships an AN UYK 20 is placed in the line between the CDS computer and the crypto device CDS Computer The central processor of the Combat Direction System 15 the CDS computer Keeping a data base of tracks is among the many functions of the operational ANTENNA RADIO Figure 4 2 The Link 11 communications system 4 2 program The information about these tracks can be transmitted to other units over the Link 11 net The computer sends data to the data terminal set using 24 bit data words The computer also receives information about remote tracks from other units in the net and displays these tracks through the display system Shipboard Gridlock System Gridlock is the matching of track positions held by other ships with the tracks held by your own ship Gridlock is a procedure for determining data registration correction by comparing remote tracks received from a designated reference unit to local data Ideally tracks received from remote units that are also displayed by onboard sensors should be transparent that is in the exact same position on the CRT If the gridlock system does not provide correlation between local and remote tracks the remote tracks may be painted twice and overlap each other as shown in figure 4 3 S8NPO1 45 ha AN Figure 4 3
253. o 40 of these DEOBs After the initial data is loaded the aircraft 1s disconnected from the DEOB but it continues to receive alignment data until the launch Then the aircraft system reverts to its original tactical condition LINK 4A MESSAGE FORMATS The following are the three types of messages used in the Link 4A system control messages reply messages and test messages These messages use two basic formats Control messages are transmitted from the controlling ship to the aircraft Reply messages are transmitted from the aircraft to the control station The timing for Link 4A communications is determined from the duration of the transmit and receive cycles The standard CDS control messages are 14 msec in duration while the receive cycle for reply messages is 18 msec in duration The CAINS system does not use reply messages therefore a 2 msec receive cycle is substituted to allow time for the Link 4A data terminal set to initialize the next message Thus we have the following two timing cycles 14 18 control message 14 msec receive cycle 18 msec and 14 2 control message 14 msec receive cycle 2 msec 6 3 CONTROL MESSAGE FORMAT Control messages are assembled and transmitted during the 14 msec transmit frame shows the standard structure of a Link 4A control message During the transmit frame the transmit key signal and the control message pulse train are sent to the radio set transmitter The transmit frame is divided
254. of bits that have to be transmitted Provides data encryption for privacy and authentication APPLICATION LEVEL LAYER The final level is the application level which consists of the application layer The application layer serves as the window for the application process to access the OSI environment This layer represents the services that directly support users and application tasks It contains a variety of commonly needed protocols for the following items Network virtual terminals e File transfers Remote file access Electronic mail Network management USING THE OSI MODEL A communications system that does not use a layered architecture can be designed A specifically designed communications system is faster more efficient requires less software code and eliminates redundant functions and activities Why then is the OSI reference model considered the standard in designing networks and writing software It 18 considered the standard primarily because the use of a layered architecture such as the OSI reference model provides the network with flexibility and migration The greatest advantage of your using layer architecture in a network is hardware independence As advances in technology continue it is not necessary to scrap a network completely because one component has been superseded For example if you have a network and need to upgrade the cable to a type that can handle increased data at
255. of sight 2 12 modulation 1 4 multiplexing 2 13 radio communications 1 1 safety 1 1 satellite 3 1 space diversity 2 19 syncros servos 1 13 system 2 1 transceivers tropospheric scatter 2 13 TTY facsimile INDEX Communications Link Interface Planning System Communications Systems Equipment Coniiguratiom AFTS 2 23 Fleet Satellite 3 4 hf 2 5 if 2 4 microwave 2 10 RFCS 2 22 SAS 2 14 Shf 2 9 uhf 2 8 Vhf 2 7 vif 2 3 CP 2205 P V USQ 125 Data Terminal 7 1 E Enhanced Link Quality Analysis 7 2 Equipment ancillary frequency standards portable and pack radios 2 24 SATCOMI 3 23 TTY sets 2 20 EtherNet F FLTSATCOM INDEX I control subsystem 3 16 CUDIXS subsystem 3 6 DAMA subsystem 3 15 Fleet Broadcast subsystem 3 4 NAVMACS subsystem 3 6 OTCIXS subsystem 3 14 Secure Voice subsystem 3 10 FLTSATCOM Continued SSIXS subsystem 3 9 TACINTEL subsystem 3 11 TADIXS subsystem 3 13 teletypewriter subsystem 3 13 FLTSATCOM shorebased terminals 3 3 I IBM Token Ring J Joint Tactical Information Distribution System LINK 1 6 7 4 Link 16 data exchange 7 6 Link 16 nets 7 6 JTIDS terminal 7 9 JTIDS architecture 7 6 JTIDS 7 4 L LAN topologies 8 7 Distributed star network 8 9 Linear bus network 8 7 Ring network 8 9 LAN protocols 8 10 LAN access methods 8 10 Contention 8 10 Token pas
256. ogated If a start code is not received after another 15 frame intervals the address control unit will advance to the next active picket address and the interrogation process is repeated The other major difference is when the net control station has completed its own tactical data transmission a control stop code followed by the next station address is transmitted Again if a start code 15 not received within 15 frame intervals a This interrogation is a normal interrogation message second interrogation is sent second consisting of the preamble phase reference frame and address code Modulator Demodulator The modulator demodulator function of the DTS provides the digital to analog and analog to digital conversion During data transmission the 24 bit binary data word 1s expanded to 30 bits by adding the six bits for error detection and correction The 30 bits are then examined in pairs to determine the required phase angle shift for each of the 15 data carrying tones in the audio package At the frame boundary the phase of each data tone is shifted with respect to the previous Figure 4 19 shows the four possible phase shifts A sixteenth tone the 605 Hz Doppler correction tone is added to the tone package The Doppler tone is not phase modulated and is used to correct for Doppler shifts caused by the relative motion between the transmitting station and the receiving station The 16 tones are combined into a c
257. olor graphics adapter CIGARS console internally generated and refreshed symbols CIU computer interface unit CONICS circles and ellipses CP clock pulse CPS cycles per second CRO TV monitor CRT cathode ray tube CTRL control dB decibels DCC display control console DCI direct computer interface DDEU digital data entry unit DDI 1 digital data indicator 2 digital display indicator DITEG digital television graphics generator DIV diversity DLRP Data Link Reference Point DMU display multiplexer unit DRAC digital radar azimuth converter DSC digital scan converter DTS data terminal set EDAC error detection and correction EF word external function word EGA enhanced graphics adapter EMI RFI electromagnetic interference radio frequency interference EPROM cerasable programmable read only memory ESC key escape key FM frequency modulation GUI graphic user interface HF high frequency HVPS high voltage power supply HZ hertz input output IFF SIF identification friend foe selective identification feature JTIDS Joint Tactical Information Distribution System J SERIES MESSAGE tThe fixed format messages containing tactical data and commands that are used to exchange information over the JTIDS system JU JTDS Unit LCD liquid crystal display LCL
258. ome across all of them Now that we have identified the satellite communications subsystems we need to provide you with a basic understanding of how they operate But first we need to discuss FLTSATCOM Shorebased Terminals FLTSATCOM SHOREBASED TERMINALS SATCOM installations at shore terminals operate from existing naval communications centers and certain command operations centers Four Naval Computer and Telecommunications Area Master Stations NCTAMS have primary responsibility for naval communications via satellite They are NCTAMS LANT Norfolk Virginia NCTAMS MED Naples Italy e NCTAMS WESTPAC Finegayan Guam e NCTAMS EASTPAC Wahiawa Hawaii The Naval Computer and Telecommunications Station NCTS San Diego California as part of TADIXS provides connectivity between NCTAMS EASTPAC and NCTAMS LANT Ten NCTSs are used to retransmit Fleet Broadcast message traffic via hf links In addition an rf terminal at Yokosuka Japan transmits SSIXS and Secure Voice communications to the western Pacific and Indian Oceans Also there is landline connection between Japan and NCTAMS WESTPAC to support TADIXS and OTCIXS transmissions Within these facilities each subsystem consists of two parts the baseband equipment used to collect and control the transmitted or received communications and the rf terminal used by the baseband system to transmit and receive via satellite link Some subsystems have the baseband e
259. ome of the causes for this condition could be the following NCS having an incorrect PU address entered in the DTS low transmitter power out from NCS an excessively noisy frequency or weak PU receivers 5 19 52 52 54 a 54 72 72 06 6 opm pt 0 _ 38NP0210 Figure 5 17 Several PUs not responding to NCS call ups The LMS 11 also has several off line modes that allow you to save data onto a disk and analyze the data in detail The off line modes include a frame by frame display to analyze each frame of a transmission This allows you to analyze the data of a particular PU and shows the status of each bit position Remember that when you are doing a frame by frame analysis the data has not been decrypted More information on all modes of the LMS 11 can be found the System Operation and Maintenance Instructions Organization Level Link Monitor System AN TSQ 162 V 1 EE 190 AB OMI 010 TSQ 162 V 1 CHAPTER 6 LINK 4A INTRODUCTION The Link 4A system is a fully automatic high speed data transmission system used for aircraft control The system provides controlling information to the aircraft using radio transmission between the controlling ship and the controlled aircraft The Carrier Aircraft Inertial Navigation System CAINS is also a part of the Link 4A system The CAINS system is used to load alignment and way point data into the aircraft on the flight deck or the hangar deck
260. omposite audio signal and sent to the radio set The radio composite tone package on the carrier frequency in independent sideband form set transmits the 225 SHIFT T SHIFT 38NP0162 Figure 4 19 Link 11 frame boundary phase shifts During receive operations the tone package is received from the radio set The 30 bits of data are extracted from the tone package by determining the phase shift of each data tone with respect to the previous frame The 30 bits which contain 24 data bits and six EDAC bits are examined for errors The six EDAC bits allow for the detection of errors and provide enough redundancy to allow for correcting a single bit error The operator can select whether or not the DTS attempts to correct detected errors as explained earlier in this chapter In the error detect label mode a detected error is identified and labeled before it 1s sent to the CDS computer In the error correction correct mode the DTS attempts to correct a detected error labels the error and sends the data word to the CDS computer The DTS is capable of receiving and processing both the upper sideband and the lower sideband when using a HF radio depending on the position of the sideband select switch When you are using a UHF radio only the upper sideband is received and processed If the sideband select switch is in the USB or the LBS position only the designated sideband is processed In the diversity DIV mode th
261. on interface cables Line discipline full or half duplex Pin assignments Data Link Layer The data link layer provides error free transmission of information over the physical medium This allows the next higher layer to assume virtually error free transmission over the link The data link layer is responsible forgetting data packaged and onto the network cable It manages the flow of the data bit stream into and out of each network node as follows Creates and recognizes frame boundaries Checks received messages for integrity Manages channel access and flow control Ensures correct sequence of transmitted data The data link layer detects and when possible corrects errors that occur in the physical layer without using the functions of the upper layers It also provides flow control techniques to ensure link buffer capacity is not exceeded TRANSPORT LEVEL The next three layers of the OSI reference model make up the transport level also known as the subnet The transport level defines the software protocols necessary to exchange data on the network The three layers of the transport level are the network layer the transport layer and the session layer Network Layer The network layer decides which physical pathway the data should take based on network conditions priorities of service and other factors Software on the network interface card must build the data packet so the network laye
262. on Jw Gyro 4 Compass When you use subdivisions to assign reference designators to equipment what is the designator of the a largest subdivision and b smallest subdivision ie a System b set 21 a Set b unit e a System b part 4 a Unit b assembly Extremely low frequency transmission is primarily directed at which of the following users l IAlrcGratt 2 Shore installations 3 Submarines 4 Surface ships 1 29 I A 19295 1 29 The very low frequency receive system is designed to receive what types of signals 1 AM and FM 2 FSK and CW FOK vane Cw 4 SSB and FSK The AN FRT 72 if transmitter is used to provide a how many channels of frequency division ioe multiplex rtty traffic over b what type of fleet broadcast system at c what type of power a EIGNE Co multrenannel c eg 2 a Eight b singlechannel GO Airgh SM a Four b multichannel c low 15335 4 Four b multichannel c mpg HF communications from shore based transmitters to ships at sea using frequency and space diversity is an example of which of the following types of Systems 1 54 1 Fleet broadcast De POING CO COLNE 35 Ground to ailr 4 ship to shore Which one of the following equipment would you use to match a transmitter s output impedance to an antenna s input impedance l V 24290 2v GB 9989 79RI 393 3 AN UCC 1 4 AN URA 38 The AN VRC 80 is
263. on The keyboard provides the operator interface with the LMS 11 COLOR DISPLAY MONITOR The color display monitor is capable of displaying both composite and RGB video The computer generates composite video during the start up and testing of the LMS 11 The RGB input with an external sync is used for displaying graphics during normal LMS 11 operations The monitor is also equipped with a speaker and audio input to provide the operator with the capability of monitoring the Link 11 audio signal KEYBOARD The keyboard is mounted on a tray under the monitor Under the tray there is a storage slot for the LMS 11 technical manual The functional keys on the keyboard are color coded to facilitate operator selections and entries The LMS 11 keyboard is shown in figure 5 4 Many of the keys on the LMS 11 keyboard are not used and the software does not recognize these keys The actual functions of the keys are covered later in this chapter Accessory Group AG The accessory group contains a color graphics printer and spare parts and supplies for the LMS 11 The shipping container is also used to store the DPG and CDG container covers when the printer is removed and mounted on the LMS 11 The color graphics printer is used to provide hard copy printouts of the display screen on plain paper or clear transparency material LMS 11 OPERATION AND DISPLAYS The LMS 11 provides real time monitoring of Link 11 operations Problems wit
264. on control panel the mode control panel the TADIL A control panel and the address control panel TADIL A Control Panel The TADIL control panel provides the control switches and indicators required to control and monitor Link 11 operations Figure 4 16 shows the AN USQ 59 TADIL control panel XMT DATA ERROR INDICATOR This indicator is lighted when the DTS detects an error while transmitting data in the TADIL or Link 11 mode RCV DATA ERROR INDICATOR This indicator is lighted when the DTS detects an error in received data being sent to the CDS computer CODE ERROR INDICATOR The CODE ERROR indicator is lighted when the DTS detects an error in the received or sidetone transmit control codes during TADIL A operations NET BUSY INDICATOR The NET BUSY indicator is lighted when the DTS detects that the communications net 15 busy It is activated when signal called signal presence is generated by the DTS SYNC COMPT INDICATOR The SYNC COMPT indicator is lighted continuously or flashes when the DTS has achieved synchronization with the NCS data terminal TIMING STORED CORRECTED SWITCH The TIMING STORED CORRECTED switch determines how the DTS is synchronized When the switch is in the CORRECTED position the fast synchronization and or the continuous synchronization circuitry in the DTS is used The position of the sync mode switch on the mode control panel determines whether the fast
265. on of power in the Link 11 data tones H CO BRO LE CO p rn The PU display of the LMS 11 presents a graphic representation of the relative power and phase error of the Link 11 signal received from a specified unit 1 True 2 False What information is displayed on the relative power bar graph of the PU display 1 The power of the 605 Hz tone only 2 The relative power of the data tones with respect to the 605 Hz tone 3 The relative power of each data tone with respect to the average power of all the data tones 4 The relative power of each data tone with respect to an internal standard When the relative power bar graph is read a data tone that is 2 dB greater than the average will be displayed in which of the following colors Cyan Green Yellow Red H CO N I The phase error bar graph of the LMS 11 display what information about the Link 11 signal 1 Relative power 2 Mean deviation of the phase error only 3 Standard deviation of the phase error only 4 Both the mean and standard deviations of the phase error 26 4 71 A12 wee oe 4 14 A standard phase deviation of 15 degrees for a data tone will be represented on the bar graph in which of the following GOODS Lc Son 2 Green 3 Yellow 4 Red The LMS 11 will indicate that the data received is bad if the standard deviation falls in which of the following ranges 1 A positive value less than 45 degrees 2 A p
266. on the up link It has two antenna beams 1 a dual frequency spot beam steerable by ground command and 2 an earth coverage beam that uses separate horn antennas for transmit and receive LEASAT SATELLITE The LEASAT satellite has seven 25 kHz uhf down link channels one 500 kHz wide band channel and five 5 kHz channels One of the seven 25 kHz down link channels is used for Fleet Broadcast The broadcast up link is shf with translation to uhf taking place in the satellite The remaining six channels function as direct relay channels with separate repeaters A LEASAT satellite 1s shown in figure 3 18 Compared to FLSATCOM satellites LEASAT satellites have a reduced number of 25 kHz channels However they can still serve expanding Navy SATCOM requirements by using the groundbased DAMA technique effectively using each satellite channel more efficiently UHF FOLLOW ON SATELLITE The purpose of the Ultra High Frequency Follow On Satellite System F O is to provide satellite communications for DOD and other government agencies through satellites in geosynchronous orbit The current satellites GAPFILLER FLTSATCOM and LEASAT are approaching the end of their normal mission life F O will provide the needed replenishment satellites The strategy for replacement is to use existing FLTSATCOM and LEASAT assets fully while deploying the UHF F O satellites to minimize communications disruptions as the FLTSATCOM and LEAS
267. ons 1 Depress the history mode key on the keyboard 2 Enter a zero into the SUMMARIZE field of the Net Display header 2 Enter the PU number Of the unit to be monitored in the PU field 4 Both 2 and 3 above hs On the Net Display screen which of the following values indicates an unacceptable SNR dB 2 do HB 2e 20208 4 34 dB When the LMS 11 is in the Net Display summarize mode which of the following conditions will cause the FRAME CNT value of a picket to be displayed in yellow and followed by a 1 The average number of frames per transmission exceeds seven 2 The average number of frames per transmission is six or less 3 The average signal to noise level per transmission exceeds 20 dB 4 The average signal to noise level per transmission is less than 20 dB The sTHRU column of the Net Display screen displays which of the following values 1 The percentage of data received by the listed PU that is error free 2 The percentage of message data frames received by the LMS 11 that contains errors 3 The percentage of message data frames received by the LMS 11 that are error free 4 The percentage of control code frames received Which of the following power levels listed in the REL 605 column of the Net Display Screen indicates normal operation of the link hr sar dD Zu 608 Se S AB 4 6 dB 1606 Using TADIL A specifications what is the maximum allowable variati
268. ons will enable you to say with complete confidence this communications suite is operational SAFETY Hazards encountered in servicing electronic equipment and the precautions to be taken against them are covered thoroughly in Electronics Techni cian Volume 1 Safety NAVEDTRA 12411 and the General Handbook NAVSHIPS 0967 000 0100 of the EIMB series Safety 15 everyone s responsibility Observance of safety precautions will keep your equipment operat ing help your career in the Navy and possibly deter mine whether or not you survive Always follow the appropriate safety precautions Note Equipment that we cover in this other chapters is intended to be merely repre sentative of equipment that you may encounter on board your command We will not attempt to include all the possible equipment or equipment configurations BASIC SYSTEM REQUIREMENTS Radio equipment can be divided into three broad categories transmitting equipment receiving equipment and terminal equipment Transmitting MEDIUM EARTH S ATMOSPHERE PORTION OF RADIO WAVE INTERCEPTED BY oA RECEIVING ANTENNA TRANSMITTING RECEIVING ANTENNA ANTENNA TRANSMISSION TRANSMISSION LINE LINE RECEIVER ETV30001 Figure 1 1 Basic radio communication system 1 2 equipment generates amplifies and modulates a transmitted signal Receiving equipment receives a radio wave then amplifies and demodulates it to e
269. ophisticated systems the network interfaces can also provide for bridging a new network into an operating network without having to rebuild the Operating system File Systems The file system controls the way the data 15 organized stored and retrieved from the storage systems available to the network The files may be stored on hard drives RAM disks or optical storage devices such as CD ROM write once read many WORM drives File systems are generally designed to provide universal applicability This means that the file system can be compatible with any application program s expectation of file input output protocol When adaptable interfaces are used the file system can appear to emulate a number of different file systems System Extensions The system extensions define the openness of the network operating system and are used by third party developers to produce add on products The extensions are usually high level protocol handlers that perform operations such as file access protocol translations required by different operating systems The extensions available also include network management system tools and data base services 8 13 System Services Network system services contain all services that are not easily defined by any of the other areas of the network Examples of network services are security system reliability features error conditions and access violations NETWORK OPERATING SYSTEMS SOFTWA
270. orbital parameters are the main limitations to a satellite communications system Two additional limiting factors for active satellites are transmitter power and receiver sensitivity Energy for electricity 1s limited to whatever can be produced by the solar cells which limits the satellite s output power This problem is made worse by users who increase their output power to the satellite causing the satellite to try to retransmit at the new power level at the expense of reducing signals to other users FLEET SATELLITE COMMUNICATIONS The Fleet Satellite Communications FLTSATCOM System provides communications via satellites between designated mobile units and shore sites These links provide worldwide coverage between the latitudes of 70 degrees north and 70 degrees south Three satellites are currently in use with a fourth to come online soon GAPFILLER LEASAT FLTSATCOM and Follow on UFO System installations are located on ships submarines mobile vans aircraft and shore stations Though these installations could operate separately integrating the system provides message traffic and voice communications to all DOD long range communications networks In addition certain shore stations provide a back up capability to other users in case of an outage of any kind which maintains net connectivity The Navy SATCOM system consists of information exchange subsystems that use the satellites as 1 relays for communica
271. ormula 2 Comparison of the raw analog signal with the preceding frame 3 Phase shift signal from the DIS 4 Digital data from the crypto device The control display group consists of which of the following units 1 Composite video and color Output Card assemblies 2 Data communications interface and HP interface bus 3 Color monitor and keyboard 4 Color printer and interconnecting cables 4 39 The color display monitor of 4 44 the LMS 11 uses composite video when it performs which of the following operations 1 Normal LMS 11 operations 2 Start up Operations only 3 Testing operations only la Both start up and testing operations 4 45 The functional keys on the LMS 11 keyboard are color coded to facilitate operator selections and entries 1 True 2 False D ring of the LMS 11 which of the following operator entries is NOT a 4 15 required entry 4 46 1 Date and time 2 Own ship PU number 3 Net mode 4 Data rate When initializing the LMS 11 the operator enters 127 frames as the CALL TIMEOUT value What type of Link 11 operation is indicated by this entry 4 47 lx NEI TESI 2 Normal roll call mode 3 Satellite link operation 4 NET SYNC The link monitor mode of the LMS 11 displays what information 4 48 1 Quantitative information concerning the operation of a maximum of 21 PUs 2 Detailed characteristics of the received signal from a speci
272. ositive value greater than 45 degrees 3 A negative value less than 45 degrees 4 Both 2 and 3 above Ihe incidence of bit errors will increase as the signal to noise ratio increases 1 True 2 False Which of the following tones are graphically displayed by the LMS 11 Spectrum Display 1 30 tones that are the harmonics Ob 55 AZ 2 30 tones that are the even harmonics of 55 Hz 3 The 605 Hz tone and the noise tone only 4 The 15 data tones only Under ideal conditions at what level should the data tones be displayed on the bar graph of the spectrum display 1 0 dB 2 FO dB 3 02088 4 4 dB Textbook Assignment Sela Des gs Seu ASSIGNMENT 129 6 6 pages 7 1 through 7 6 continued When the operator enters PU 00 o into the PU address field of the spectrum display what effect if any will it have on the operation of the LMS 11 1 00 is an illegal address therefore no data will be displayed 2 The LMS 11 will continuously update the display for each unit in the net 3 The LMS 11 will update the display for NCS only a Os 4 No effect the LMS 11 will continue to update the last legal address entered Carrier suppression can only be tested when the Link 11 system is operating in which of the following modes 1 Net Test eet 2 Net Sync 3 Roll call 4 Broadcast When reading the LMS 11 spectrum display the technician notices that only the
273. ot be included in the multi station POFA The multi station POFA should be run using the same frequency as the current operational frequency After running the single station POFA NCS should direct all participants to go to Radio Silence During this time all stations should monitor the assigned frequency for noise The frequency can be monitored through the headphones or by using a frequency analyzer A noisy frequency can cause errors in the multi station POFA If the frequency is too noisy consider using an alternate frequency Once the frequency has been checked NCS will tell all participants to prepare to receive POFA After all stations report that they are ready NCS initiates the POFA stations monitor the POFA and check 5 5 the control panel of the DTS for errors After a minimum of 5 minutes NCS terminates the POFA When the POFA is terminated a printout is generated The final step in running a multi station POFA is the analysis of the printout Analyzing Multi Station Results Running a multi station POFA closely approximates actual link operating conditions To analyze the printout fully the technician needs to be aware of some of the factors that can affect link operations When the printout is completed the analysis is easier to complete if the technician records the following information on the printout Which station is NCS e Distance and relative bearing of all participating units
274. oward acceptance and conformance to these standards Ideally if the hardware network software application software and cabling were all supplied by the same manufacturer there would be relatively few problems for users to contend with when designing and implementing a network Everything would work together rather smoothly However a computer manufacturer s architecture can make it difficult to interconnect hardware offered by other competing manufacturers or vendors The protocols used by communications devices are also highly complex and are often completely different from one manufacturer to another Then there is the network software Usually the network software from one LAN vendor will not work with that of a competitor neither will the application programs Even the cabling must be selected for a specific local area network HARDWARE LEVEL The hardware level contains the first two layers of the OSI reference model They are the physical layer 8 5 and the data link layer These are concerned primarily with the actual hardware used in a network Physical Layer The physical layer is concerned with the transmission of the unstructured raw bit stream over a physical medium It describes the electrical mechanical and functional interfaces to the carrier The physical layer carries the signals for all the higher layers as follows Voltages and pulse encoding of bits Media and media connectors NIC and so
275. p AMPLIFIER YN N ETV30005 Figure 1 5 FM transmitter block diagram We can make ssb even more efficient by removing one of the sidebands By filtering out one of the side bands before it reaches the power amplifier all the transmitter energy is concentrated into one side band instead of being split between the carrier and two sidebands This allows us to use less power for transmission Other advantages are a narrower re ceiver bandpass and the ability to place more signals in a small portion of the frequency spectrum is a block diagram of a ssb transmitter RECEIVERS Earlier you were introduced to one link in a com munications system the transmitter All that is needed to complete the system is a radio receiver receiver A A A M 1 Uil processes modulated signals and delivers as an output a reproduction of the original intelligence The signal can then be applied to a reproducing device such as a loudspeaker or a teletypewriter RECEIVER FUNCTIONS To be useful a receiver must perform certain basic functions These functions are reception selection de tection and reproduction Reception Reception occurs when a transmitted electromag netic wave passes through the receiver antenna and in duces a voltage in the antenna N T AAAA NNN L jJUUU IIl VV YV Area r s poen sen fte eese ces nutu VU VV mt QA
276. pacity and high quality communications This information will be crucial to you in understanding the communications technology of both today and the future After completing this chapter you should be able to Recognize satellite communications fundamentals e Identify fleet SATCOM subsystems and shore terminals e Evaluate specific SATCOM equipment and racks SATELLITE COMMUNICATIONS A passive satellite simply reflects radio signals back FUNDAMENTALS to earth One station transmits to the satellite on the uplink frequency The satellite translates the signal to A typical SATCOM link uses an active satellite the downlink frequency amplifies the signal then that receives and retransmits and two earth terminals transmits it to the receiving terminal Figure 3 1 shows oO N nr AIRCRAFT iN BN CQ TERMINAL g INN i 7 N N LE Ld N FIXED REE Tre 2 4 2 N bm semane __ gt 9 Pi SHIP TERMINAL d NAP va i C ETV3039 dp gt Figure 3 1 Satellite communications system 3 some of the various earth terminals and how they interface The end use or purpose determines the system s complexity and how the system is used ROLE OF SATELLITE COMMUNICATIONS SATCOM links one of several kinds of long distance communications links interconnect com municat
277. pment and racks Identify the composition of the Link 11 system and problems in Link 11 communications Recognize the functions of the Link 4 A systems new technology in data communications and local area networks THE COURSE This self study course is organized into subject matter areas each containing learning objectives to help you determine what you should learn along with text and illustrations to help you understand the information The subject matter reflects day to day requirements and experiences of personnel in the rating or skill area It also reflects guidance provided by Enlisted Community Managers ECMs and other senior personnel technical references instructions etc and either the occupational or naval standards which are listed in the Manual of Navy Enlisted Manpower Personnel Classifications and Occupational Standards NAVPERS 18068 THE QUESTIONS The questions that appear in this course are designed to help you understand the material in the text VALUE In completing this course you will improve your military and professional knowledge Importantly it can also help you study for the Navy wide advancement in rate examination If you are studying and discover a reference in the text to another publication for further information look it up 1997 Edition Prepared by DSCS SW AW Robert M Maynard Published by NAVAL EDUCATION AND TRAINING PROFESSIONAL DEVELOPMENT AND TECHNOLOGY CENTER NAVSUP Logistics Tracking Num
278. properly strict adherence to the correct message format and net protocol are required Every Link 11 message has a specific format and function Each Link 11 message generated by the DTS begins with a header consisting of the preamble five frames and the phase reference frame one frame Control codes such as the start code the picket stop code and the control stop code are also required Preamble The preamble as previously covered consists of a two tone signal The two tones are the 605 Hz Doppler tone and the 2 915 Hz sync tone The preamble is five frames long and is transmitted at four times the normal power as shown in figure 4 5 Normal power for the 605 Hz Doppler tone is 6 dB and the data tones including the 2 915 Hz tone is 0 dB During the preamble the 605 Hz tone is transmitted at 12 dB and the 2 915 Hz sync tone is transmitted at 6 dB The sync tone is shifted 180 degrees for each frame to allow the receiving DTS to detect frame transitions 605 Hz The preamble is transmitted at 4X normal power FRAME 1 2 3 4 5 PREAMBLE Figure 4 5 The Link 11 preamble power levels and frame count Phase Reference Frame The phase reference frame follows the preamble and is shown in figure 4 6 This frame is composed of the normal 16 tone composite signal with the data tones transmitted at 0 dB and the Doppler tone transmitted at 6 dB Since the two bits of data stored in a tone is based on a certai
279. quipment and rf terminals in the same building while others have the baseband equipment installed at a remote facility located some distance from the rf terminal Most subsystems use a common rf terminal However the Fleet Broadcast has an rf terminal specifically designed for that subsystem FLEET SATELLITE BROADCAST SUBSYSTEM The Fleet Satellite Broadcast Subsystem provides the capability to transmit Fleet Broadcast message traffic in a high level jamming en vironment The subsystem has 15 subchannels of encrypted message traffic at an input data rate of 75 bps per channel These subchannels are time 3 4 division multiplexed and are transmitted in a one way rf transmission at 1200 bps The shore terminal transmits this data on a direct sequence spread spectrum shf signal to the satellite where the signal is translated to uhf and down linked to the subscriber Figure 3 2 shows block diagram of the Fleet Satellite Broadcast Subsystem The High Speed Fleet Broadcast HSFB is a planned upgrade to the Fleet Satellite Broadcast Subsystem This upgrade will improve broadcast transmission speed information through put capabil ity of equipment to process or transmit data during a specific period of time and flexibility Message Traffic Input The Fleet Satellite Broadcast message traffic is queued and or channel selected by two processor controlled message switching systems before transmission These systems are the
280. r Se W Link 11 is designated as which of the following types of tactical data informatio Link 1 TADIL A 2v TADE C LADLE a 4 Teletype Link ll communications can operate with which of the following radios 1l 2 only 3 Either HF or UHF 4 VHF only When Link 11 is operated with UHF radio it is capable of overethe horrz9on8 communications 1 True 2 False QOnpu er Cryptographic Device Data Terminal Set Communications Switchboard Radio Set Figure 3A IN ANSWERING QUESTIONS 3 4 THROUGH g ie SELECT FROM FIGURE THE EQUIPMENT THAT PERFORMS THE FUNCTION DESCRIBED IN THE OUESIION ITEMS IN IHE LIST MAY BE USED THAN ONCE Seng Selects the HF or the UHF transceiver wN ES m E OQ W 11 355 3594 S rue 3 9 S eue Encrypts parallel data from the CDS computer and passes the encrypted data to the data terminal set B Ww gt Correlates reported positions of local and remote tracks GND Outputs 24 bit data words to the security equipment via the COMDUTEr S OU Pp Multiplexes and modulates parallel data into audio tones 1 Zo 3B Du VG 4 D Receives the audio tone package from the data terminal set and transmits the tones D CO he H OO Demodulates the audio tones and checks the six hamming bits for transmission errors gt
281. r 7 8125 milliseconds in duration When a JU transmits data the frequency that the data is transmitted on is changed every 13 microseconds usec according to a predetermined pseudo random pattern Link 16 uses 51 different frequencies for data exchange This frequency hopping adds to the security and integrity of the system by making it nearly impossible to jam Link 16 Nets Link 16 has the capability to handle multiple nets A Link 16 net is a group of participants sharing 7 5 mutually beneficial tactical information For example using the Link 11 system a net is formed by a group of participants These participants operate on the same frequency A separate net is formed when another group of participants operates on a different frequency The second net would be used by participants involved in a fleet exercise that wouldn t want the exercise data to interfere with the normal tactical net The controlling station and aircraft using Link 4A is also a net Link 16 has the ability to form multiple nets The Link 16 system has 128 numbers used to designate particular nets 00 127 Net number 127 is reserved to indicate a stacked net A stacked net is formed by setting up the time slots so that they have the same set initial slot number and recurrence rate When the system is initialized the use of net number 127 indicates a stacked net is to be used and the operator can then specify locally which net to use for operations
282. r at shore installations It performs differential phase shift keying DPSK modulation and demodulation of a C 9219A USC MD 905A USC 6200 6 Figure 3 28 Modem Group OM 43A USC 3 29 serial data stream at data rates of 75 300 1200 2400 4800 and 9600 bits per second This modem can be operated in fill duplex although normal operation is half duplex Modulator Demodulator OM 51A FR This modem is an integral part of the Fleet Satellite Broadcast subsystem It is a spread spectrum wide bandwidth with frequency modulation of a transmitter and receiver in exact synchronization type modem used with the AN FSC 79 satellite communications terminal to provide rf transmission capability in a high level jamming environment Shown in figure 3 29 its basic function is to provide rf analog and digital conditioning circuits and frequency synthesizing for dual redundant transmission and reception It interfaces with the AN FSC 79 terminal and the AM 6534 SSR 1 amplifier convertor 9 n re ee e RR D 5 oo T3 ETV30067 Figure 3 29 Modulator Demodulator Group OM 51A FR ee gt Em m e a es un un M e T r3 This installation consists of standard cabinet containing seven assemblies a summary control pan
283. r can recognize and route the data to the correct destination address It relieves the upper layers of the need to know anything about the data transmission and switching technologies used to connect the systems It is responsible for establishing and terminating connections across the intervening maintaining communications facility as follows Addresses messages e Sets up the path between communicating nodes on possibly different networks Routes messages among networks Is concerned with the sequence delivery of data packets Controls congestion if too many packets are on the network Translates logical addresses or names into physical addresses Has accounting functions to count packets or bits sent by users to produce billing information Transport Layer The transport layer makes sure data units are delivered error free in sequence without losses or 8 6 duplications It relieves higher layer protocols from any concern with the transportation of data between them as follows Message segmentation Accepts data from the session layer splits it up into smaller units and passes the units down to the network layer Establishes and deletes host to host connections across the network Multiplexes several message streams onto one channel and keeps track of which message belongs to which connection Provides reliable end to end delivery with acknowledgment Provides end
284. ransmission request must be sent by message to the Secure Voice controller A small ship uses the CUDIXS NAVMACS network for the message The submarine may transmit a voice channel request during a random access time period in the SSIXS In both cases the request is passed from the reception point ashore to the voice controller The voice controller coordinates the voice transmission by assigning a voice channel contacting the unit that will receive the voice transmission and following through with the transmission Radio Wireline Interface The Radio Wireline Interface RWI was developed to access and interconnect existing and future Secure Voice subsystems and equipment It pro vides the capability to connect shorebased worldwide _ sanean A cHsn NV ASW VIN A 2Z HSN NV 7189 7 JONHINOO uiajs sqns TALNIOVL paoms3guoo VjNVq 8 amsn S3uvdS JOVANI t EW A m B9 881 269 99798581 ANA QU IS gib vua url KNIE LUN SIVU TSNNVHS TSLNIOVL S1O9Ild30 LINSWdINOS JHL ALON i A o u o j gt iO 0 fm O iO 5 LM osn t N erino RET ae 41089 A OZ HAN ee ee ee ee HOSS32O0Hd
285. re 2 8 On the transmit side of the nonsecure voice system the operator at a remote location talks into the handset The handset 15 connected to a C 1138 radio set control The radio set control is connected to an SB 988 SRT transmitter transfer switchboard which is connected to the transmitter On the transmit side of the secure voice system the operator talks into the secure voice remote phone unit RPU The RPU is connected to the secure voice matrix which is the tie point for the connection of multiple remote phone units The matrix output is fed to the secure voice equipment that encrypts the information This encrypted information is then fed to an SB 988 SRT transmitter transfer switchboard The transmitter switchboard performs the same function we described for previous systems The switchboard output is connected to the transmit side of the AN SRC 20 21 or AN WSC 3 which 1s connected TY mansmmer __ ANTENNA AN SRC 20 AN SRA 33 OR OR AN SRC 21 OA 9123 SRC OR AN WSC 3 ETV30020 Figure 2 8 Uhf transmit to AN SRA 33 OA 9123 antenna coupler The coupler output is then fed to an antenna Uhf Receive A basic block diagram of a uhf receive system is shown figure 2 9 Most of the components are the same as those used in the transmit function We will therefore identify by specific designator only the components that are unique to the receive function T
286. re equipment is tested The multi station POFA is run in the Roll Call mode using a set of known data words Figure 5 2 shows the data flow for a multi station POFA A designated unit transmits a block of 230 data words that are received by the other platforms involved in the multi station POFA The receiving computer s compare s the data against the known pattern count s the words in error and send s this count back to the original ship This transmission is known as the error status report Ideally the multi station POFA should run error free No 3 Picket Ship No 1 NCS Shi 8 195 Figure 5 2 Link 11 multi station data flow Multi Station Procedures The procedures for running a multi station POFA require coordination of all participating units For this to be a good test all units must be positioned within 25 miles of each other This is usually coordinated by the Link 11 manager in conjunction with the battle group commander Just before the time the multi station POFA is to be conducted NCS should end the operational link and direct all stations to run a single station POFA The picket station reports back to NCS when the single station POFA has been completed The picket station will also report the status of the single station error printout Any errors noted during single station POFA should be corrected before the multi station POFA or the station experiencing errors should n
287. re is enough redundancy in the EDAC to allow for correction of a single bit error The operator can control the selection of the error correction mode If the data word is not a control word the word is examined to determine if it is error free contains a correctable error or contains uncorrectable errors If the DTS is in the error detection and label mode a detected error is identified and labeled before the data word is sent to the CDS computer In the error detection and correct mode the DTS attempts to correct an error before sending the data word to the CDS computer In both modes the six EDAC bits are deleted and replaced with two parity error status bits These status bits are defined in table 4 1 Audio Tone Generation and Characteristics The DTS converts the 24 bit data word along with the six EDAC bits into a composite audio signal consisting of 16 tones This composite 16 tone signal is the data frame The tones range in frequency from 605 Hz to 2 915 Hz and are the odd harmonics of 55 Hz The specific frequencies of the tones are shown in The 605 Hz tone is used for Doppler correction and the 2 915 Hz tone is used for data and synchronization Each of the data subcarrier tones tones 2 through 16 in table 4 2 represents two binary bits of differential quadrature phase shift modulated data The Doppler tone 605 Hz is not phase modulated It is used to correct for Doppler shifts in the received tones caused by the rela
288. receiver demodulates this signal separating the audio signal below or above the assigned frequency corresponding to the mark or space required for tty transmission Usually the keyer is adjusted for 850 Hz In both the RFCS and AFTS systems the tty 425 Hz above and 425 Hz below the assigned frequency A space will be 425 Hz above and a mark will be 425 Hz below the operating frequency signal from the carrier signals pass through the panel that controls looping current Looping current is the current supplied by the tty solid state power supply The tty panel integrates AFTS systems use amplitude modulation to the tone modulated and carrier frequency shift change dc mark and space pulses into audio A basic tone modulated system is shown 1 The audio conversion is done by an audio oscillator in the tone convertor Varying the tone according to the Operators maximum operational flexibility with the characters transmitted from the tty equipment least amount of circuitry and equipment systems By allowing the tty equipment to be set up in any configuration desired this panel gives the TONE MODULATED SYSTEM TRANSMIT TIN WN NW AUDIO 4 7 NN cra gt 2 oos 3 9s T ELECTRICAL TERMINAL j 2 IMPULSES BEY ODULATED CORRESPONDING BI CARRIER 2 THE MARK AND SPACE ads SIGNALS USE eg GP a MARK AND SPACE SIGNALS TONE MODULATED SYSTEM TONE CONVER
289. rinter If an emergency or Flash precedence message on a first run is received it is printed completely regardless of whether or not a match is found For nonmatches of messages with precedence lower than Flash only the heading of the message is printed Together CUDIXS and NAVMACS provide improved ship to shore and shore to ship operational TELEPRINTER NOTE THE CUDIXS CONFIGURATION SHOWN DOES NOT REFLECT THE DELETION OF SEVEN MAGNETIC TAPE UNITS AND ONE RECORDER REPRODUCER NOT SHOWN ARE THE ADDITIONAL VIDEO DISPLAY TERMINAL TELEPRINTER AND CRYPTOGRAPHIC Figure 3 3 CUDIXS equipment configuration HDUX HIGH DATA RATE SHIP SHORE SHIP _ r 4 Y 4 AXN Y ONAN n6 cupxs Pa ee SST yy e LL d Roan Z NNG T U N Nu 5 88 Fo Ec NEN e N I n NAVCOMPARS JQ ONS oe e Lo SO 510 OO WE ZU A 51 SVP KK Vv rc Nge A ry l Ko 14 P ddp V T 4 4 2 75 2400 BAUD E PRINTERS READER PUNCH rend NEMPE Se RR SN muero vcl 75 BAUD PAPER CONTROL TE YPE TAPE PUNCH ee MAGNETIC CARTRIDGE Lo LEGEND ASC AUTOMATIC SWITCHING CENTER HDUX HALF DUPLEX
290. rminal is placed in full duplex mode This option is selected when a single station POFA is run with the radio and checks the operation of the computer interface the crypto device the data terminal and the radio LOOPBACK TEST 1 selected when running a single station POFA without the radio When you select this test option the audio Loopback test 1l 15 lines are internally disconnected from the radio and the audio outputs are connected to the audio inputs Full duplex operation is also enabled This test checks the operation of the computer interface the crypto device and the data terminal LOOPBACK TEST 2 Loopback test 2 configures the data terminal for an off line self test The audio lines are disconnected from the radio and the audio output lines are internally jumpered to the A test message is internally The receiver output is monitored for data errors parity audio input lines generated and sent through the audio circuits errors control code errors and preamble recognition Any errors detected will cause the LOOPBACK FAIL indicator to be displayed LOOPBACK TEST 3 Normal audio connections Loopback test 3 is a data terminal to radio test are maintained while the computer interface is disabled A test message is internally generated and repeatedly sent through the radio As with loopback test 2 the receiver output is monitored for data errors parity errors control code errors and preamble recog
291. rne and oceangoing terminals We will discuss the FEP and its purpose irl chapter 3 Infrared devices and lasers use even higher fre quency ranges Information on equipment using these frequencies can be found in Electro Optics volume 9 of this training series RADIO EMISSIONS The emission class of an rf transmitter is deter mined by the type of modulation used The interna tional designation system for AM and FM emissions is shown in table 1 2 It designates the rf emission by type mode and supplemental characteristics We will now discuss the basic equipment required for communications TRANSMITTERS For rf communications to take place a signal has to be generated Generating the signal 15 the job of the transmitter The following paragraphs will very briefly discuss basic transmitters and transmitter fundamen tals TRANSMITTER FUNDAMENTALS Equipment used for generating amplifying and transmitting an rf carrier is collectively called a radio transmitter Transmitters may be simple low power units for sending voice messages a short distance or highly sophisticated using thousands of watts of power for sending many channels of data voice tele type telemetry t v etc over long distances Basic transmitters are identified by their method of modulation continuous wave CW amplitude modu lation AM frequency modulation FM or single sideband ssb We will first describe the types of modulation W
292. roduce a dangerous dc voltage on the exposed plug Set How many rotary switch positions will you find on a remote transmitter CODnLbroc 1 Ze TWO os ENTOG 4 Four In AFTS to what does the term half duplex refer send only Receive only Send or receive All of the above A CO BO LE Textbook Assignment zs 2 5 25195 ASSIGNMENT 29535 pages through 3 35 Which of the following methods 2e should you use to transmit printed text 1 Facsimile 2 Single tone 3 Multiplexing 4 Sequencing In which of the following 2 1 publtrcatoone can you Lnrormatron om TEMPEST requirements MIL SIDSL650 MIESSTD lIO660 MIL SID L670 MIT SID L690 WS GO La What is the designator of any conductor intended to carry classified plain language terminating in RED equipment or the RED side of crypto equipment Coded red Primary red secondary red Terminal red Hm CO BO Of the following radios which 15 popularly known as the OLOSE Gar 1 AN CRT 3A 2 AN PRC 77 3 AN PRC 96 4 AN PRC 117 Which of the following radios provides homing and two way voice communications between liferafts and searching ships 1 AN CRT 3A 2 AN PRC 77 3 96 4 AN PRC 104 Systems Equipment Configurations Satellite Communications 2 chapter 2 pages 2
293. rolled from various locations like the bridge or combat information center TRANSMITTER TRANSFER SWITCHBOARD The transmitter transfer switchboard allows the re mote control station functions and signals to be trans ferred selectively to the transmitters shows a transfer switchboard that allows the functions and controls of anyone or all of 10 remote control sta tion functions and signals to be transferred selectively to any one of six transmitters Each knob corresponds Figure 1 11 1 12 Bo z io 9 OO 40 ETV30011 Figure 1 11 Transmitter Transfer Switchboard SB 988 SRT to a remote control station and has 8 operating posi tions Positions 1 through 6 correspond to attached transmitters The seventh position X allows for switching of the transmitters to another switchboard The eighth position OFF removes the remote from the system RECEIVER TRANSFER SWITCHBOARD The receiver switchboard allows the audio outputs from the receivers to be transferred to remote control station audio circuits A representative receiver trans fer switchboard is shown in This switch board contains 10 seven position switches Each switch corresponds to a remote control station and each switch position 1 through 5 represents a re ceiver Position X allows the circuits attached to the switch to be transferred to another switchboard ANTENNAS An antenna is a conductor or system of conductors that radiates
294. s x z oma lt c S z 4 lt coz yd ug aos S lt Qao NE NAS AB RA 42 m c lan C T gt gt gt gt gt ey New en 24 sf ul a Q Q Q 2 N 0 2 0 e 2 2 x 2 Qe v e NO E oen oO en o en 2 ay Ww Ot m OO wa uU rac Se OD CHO CHO CSO gt gt 7 gt gt DU gt op CSM ccn CSR oon zS lt 50 ico SSE FoF FOE TSE Foe M g c Oo Oo m OSs O c a Oc 22H Aza vu la gt aaa v vue Y 6 2 pO z ELO FN gt gt gt gt Pu cz I cp Z Z me 4 a O Z U a m O a 1 Modified for use with re 13 r eT che PP PU Tarr control modulation select handset control RT i T d ontains preset channel C for RT 1107 17 1 Remote control for RT e e o A a S ic n r S W 1 V teletype circuit control requires 28 volts dc for indicator A1 10 3 27 me L 471 4 A CN IN G Y Lal ISS By WN Ps SUF AVE BOE gt gt LS e gt x lt A nm C 4L POO RSS gt T nex CG te CN AMPUFIER CONVERTER FA EN ROS N nots pa y
295. s but is increased to 127 frames satellite link operations When all the required data is entered the operator should select the desired mode of operation for the LMS 11 The five on line modes are as follows LINK MONITOR NET PU SPECTRUM and CARRIER SUPPRESSION Each mode has a unique display screen AII display screens consist of the following three parts the header the link signal or information area and the status display The header is at the top of the screen and indicates the mode being displayed information area is the middle section of the display and the status display is at the bottom of the screen The status display is the same for all on line modes Link Monitor Mode The link monitor mode display reflects link activity in real time This display allows the operator or technician to monitor link operations and detect problems as they occur To select the link monitor mode the operator presses the function key labeled LM The link monitor mode display is shown in 4 HON DATE 01 15 96 0 1 19 PRINTER DATA RATE FREQ CORR CALL TIMEOUT NSYNC NTST RC FAST SLOW ON OFF 15 RC SRC 38NP0198 Figure 5 5 The LMS 11 Initialization display screen The top lines of the link monitor display screen contain the header information The LMS 11 mode is in the top center The link mode is c
296. s vice 25 kHz Provide 34 995 channels vice 7000 Similar to V 6 with AJ capability Similar to V 7 with AJ capability Similar to V 3 but modified for Trident SSBN IRR Blower flow altered Similar to V 2 Modified to operate from 400 Hz primary power Table 3 1 AN WSC 3 Variations Continued a a PN SR SP SE o 7 55 2 E E ar gt gt gt 22 oH 69 50 5 cS es 5 V 2 U s amp 8 5 d e ae gt S 28 et e cm UV Jo 2 984 gt Z 5 lt 9 u c 5 d 5 Sen 82 5 2 lt 13 0 r 7 TZ o 2 Un 5 lt 5 8 5 a e 9 ZS 8 g lt lt Be 89 85 0 V Q A Qt U Q C m 1 BSE ST ES z 1 e I 9 m 3 d oe 5 dz Da S cS gt cn pus 8 T 194 B 584 5 3 2 2 w 6 D m Un a Na g E oN e oN z m gt o p gt gt UO gt gt Sout ee m w 9 f 9 5 lt SSS uod 58 ZE E 39 2 dane Wo d o q d lt w p y e Ln 9 uL c o s
297. set AN PSC 3 components are shown in figure 2 26 One important feature of the AN PSC 3 1s its ability to interface directly with the AN PRC 70 AN PRC 77 and other vhf capable radios which provides a satellite link for vhf tactical equipment This provides away to retransmit vhf information from one of these radios by 1 converting vhf to uhf 2 transmitting through a satellite to another AN PRC 3 3 demodulating it and passing it directly to another a BATTERY BOX WITH BATTERIES INSTALLED WHIP MEDIUM GAIN ANTENNA ANTENNA AND CARRYING CASE ETV30038 Figure 2 26 Radio Set AN PSC 3 2 28 AN PRC 70 77 which could then 4 retransmit the information as vhf This greatly enhances com munications capability and extends the com munications range A basic retransmission setup is shown in figure 2 27 DIGITAL MESSAGE DEVICE GROUP DMDG The DMDG is part of the Special Forces Burst Communications System It is used with radio sets AN PRC 70 74 and AN PSC 3 to send and receive messages Messages are typed on the KY 879 P keyboard shown in figure 2 28 which displays the message as it 1s being typed and stored in memory When the message is ready to be sent the operator selects the proper mode and the device converts the message to digital information The digital in formation is sent to one of the above radios for transmission After the information 15 received at the other end it 15 sent to
298. shf and in the future ehf and hf radio links TACTICAL INTELLIGENCE SUBSYSTEM The Tactical Intelligence subsystem TACINTEL is used to transmit special intelligence communica tions A link control protocol has been adapted to a for mat required for communication across a DAMA supported channel using a polling scheme that can sup port a net membership of 23 subscribers A portion of a DAMA 25 kHz channel on each of the FLTSATCOM satellites has been allocated for TACINTEL A TACIN TEL subsystem is shown in figure 3 8 TACINTEL also processes time sensitive sensor data and other data essential to Indications and Warnings and OTH Targeting In addition this system unlike CUDIXS NAVMACS can be used for direct ship to ship interchange of this data Rf Transmission TACINTEL baseband equipment uses an rf terminal in common with other subsystems at both Shore facilities and subscriber terminals Shore facilities use an AN WSC 5 V subscribers use an SUBSCRIBER TERMINAL r EE poca TELETYPEWRITER PSK AN EXISTING TRANSCEIVER TSEC KW 7 MODEM AN WSC 3 SINGLE AN WSC 3 NOCERE eee OK 367 WSC 3 CONTROL INDICATOR OR C 9899 WSC 3 OK 326 WSC 3 AN WSC 3 V The TACINTEL channel operates as a half duplex uhf link at 1200 2400 or 4800 bps Modulation is DPSK Subscriber Reception Each subscriber has an identification number recognized by the subscriber processor
299. signal The voice frequencies about 110 3 000 Hz are contained in the audio frequency spectrum 10 20 000 Hz In val communications the terms voice communications and audio communications are sometimes used inter changeably The audio signal is impressed upon the rf carrier because it is impractical to transmit frequen cies in the audio range due to their excessive wave length Three characteristics of the carrier wave may be varied or modulated at an external signal rate ampli tude frequency and phase The following paragraphs discuss each type of modulation Amplitude Modulation AM Amplitude modulations the process of combining audio frequency and radio frequency signals so that the amplitude of the radio frequency waves varies at an audio frequency rate Frequency Modulation FM Frequency modulation is a process in which the frequency of the carrier wave is made to vary An FM signal should remain constant in amplitude and change only in frequency Frequency Shift Keying FSK Frequency shift keying is considered a form of FM It is a digital mode of transmission commonly used in radioteletype applications In FSK the carrier 18 present all the time In a keyed condition the carrier frequency changes by a predetermined amount called KEY Ee KEY i the mark frequency The unkeyed state is called a space Phase Shift Keying PSK Phase shift keying is similar to FSK except that the phase not the
300. sing 8 10 Link 11 Data Terminal Set 4 4 4 1 1 Audio tone generation and characteristics 4 1 1 Controls and indicators Mode control panel 4 13 TADIL A control panel 4 15 Error detection and correction 4 10 Link 11 message formats 4 8 Broadcast mode message 4 9 Call up interrogation message 4 9 Link 11 message formats Continued NCS report and call up 4 9 Picket reply message 4 9 Roll call message 4 8 Short broadcast message 4 9 Link 11 Monitoring System LMS 1 1 5 6 Carrier suppression display 5 17 Link monitor mode 5 9 Net 5 12 Operation and displays 5 9 PU display 5 16 Spectrum display 5 18 Status display 5 11 System initializationj5 9 System configuration 5 7 Link 11 Net operating modes 4 5 Broadcast 4 6 Net test 4 6 Net synchronization 4 6 Radio silence 4 7 Roll 4 6 Short broadcast 4 7 Link 11 system overview 4 2 Link 16 new capabilities 7 6 Link 4A CDS systemj 6 1 Link 4A message formats 6 3 Control messages 6 4 Reply messages 6 4 Test messages 6 4 Link 11 message 4 7 Information segment 4 8 Phase reference frame 4 7 Preamble 4 7 Start code 4 8 Stop code 4 8 Link 11 security device 4 3 INDEX 2 Link Monitor System LMS 4 6 6 Local area network hardware 8 3 M Maximum useable frequency MUF 7 3 Multi frequency link 7 3 Multi tone waveform link 7 2 Multi station POFA 5 5 N Networ
301. sing the radio set keyline and passes the audio tones via the communications switchboard to the transmitter for modulation to the RF carrier signal The radio set keyline is a signal that switches the radio to transmit mode when the set and receive mode when clear When you are using the HF band the radio frequency signal modulation uses amplitude modulation independent sideband that is the upper sideband USB and lower sideband LSB are transmitted independently in an effort to overcome propagation caused signal losses The radio FORMAT INTO MESSAGES OUTPUT IIS BUFFER 1 1 0 KG 40 38NPO148 Figure 4 4 Link 11 data flow for the transmit cycle wa m eA fit Modulate Nc AMAAN Transmit f Se transmitted independently in an effort to overcome propagation caused signal losses The UHF radio uses frequency modulation therefore only the USB is used Receive Cycle When a transmitted signal is received the receiver demodulates the audio tones from the RF carrier and passes them via the communications switchboard to the DTS The DTS demodulates and demultiplexes the audio tones into digital data The digital data is sent to the cryptographic device where it is decrypted and sent to the CDS computer for processing LINK 11 NET OPERATING MODES Before we look into the actual operation of the data terminal set you need
302. single sideband transmit ter or ssb Let s look at some of the advantages of ssb transmitters SINGLE SIDEBAND TRANSMITTER In ssb communications the carrier is suppressed eliminated and the sideband frequencies produced by the carrier are reduced to a minimum This means no carrier is present in the transmitted signal It is re moved after the signal is modulated and reinserted at the receiver during demodulation Since there is no carrier all the energy is concentrated in the side band s IGNAL 1 V Wn ANTENNA i MIS Al m mmy mm HAAT A T ATA ll 4101 ATH PT ne Eee errr SIGNAL PUT MT AV AMV Ya Alita i1 AAAA Viv BUFER POWER INI RF OSCILLATOR PMP 1 11 don eee UU Lo 5 1 4 9 MV 6 17 m ee A AE IN SPEECH We _ TUV 242 AMPLIFIER gt gt DRIVER FHP MODULATOR MICROPHONE Nl DC MA REM a ranc AUDIO FREQUENCY WL SIGNAL POWER SUPPLY ETV30004 Figure 1 4 AM transmitter block diagram CONTROLLED OSCILLATOR RADIOFREQUENCY F N FM WAVE OF LOW FM WAVE OF HIGH L RADIOFREQUENCY RADIOFREQUENCY FIRST SECOND A AF MICROPHONE AMPLIFIER
303. sion handshaking and for the transmission itself Transmission is conducted subject to the line discipline The line discipline is the sequence of operations that actually transmits and receives the data handles the error control procedures handles the sequencing of message blocks and provides for validation for information received correctly Two representative protocols which control line discipline are the Binary Synchronous communications Protocol Bisync and the Synchronous Data Link Control SDLC Bisync Bisync is a half duplex protocol that transmits strings of characters at lower speeds over dial up circuits The information movement is in one direction at a time with each data transfer being answered by an acknowledgement SDLC SDLC is a control procedure that sends multiple blocks of data and returns a single acknowledgement for many blocks thereby increasing the amount of time spent transmitting data The bits that are put before and after the message at the transmitting end are removed at the receiving end so only the message is presented to the user 3 gt gt gt gt gt gt gt gt gt gt gt NETWORK Im al 15A C NODE PC 2 HAS PC 2 POD 5 DATA SEND DATA TO SEND 1 TO MODE 1 Ill TO MODE PC 4 PC 4 PC 3 ani I J 38NP0191 Figure 8 7 A ring network using the token passing access method
304. sions of the AN SSW used in shipboard Link 4A systems the AN SSW 1A IB IC ID and IE The AN SSW 1A IB and IC are operationally and functionally identical as are the AN SSW 1D and 1E The major difference between the two groupings of versions is the single channel capability of the AN SSW IA B C and the dual channel capability of the AN SSW ID E Each of the dual channels is capable of the link operations of the single channel AN SSW The dual channel AN SSW ID E is also capable of transmitting CAINS data For purposes of this lesson we use the AN SSW ID E The AN SSW ID E shown in figure 6 4 consists of the following eight major subassemblies one coordinate data transfer control two digital to digital converters two monitor test panels two INTERLOCK REMOTE RADIO POWER O j OFF RADIO POWER REMOTE RADIO POWER ON SEE DDC B POWER CONTROL El RADIO POWER PEN pp DATA El 2 S NAVAL SHIP SYSTEM COMMAND 38NP0169 Figure 6 5 The coordinate data transfer control assembly AN SSW 1D E pulse amplifier assemblies and power supply assembly There are two independent equipment groups in the AN SSW 1D E Each group is capable of simultaneous operations with separate and dedicated computer input output channels and dedicated radio sets Coordinate Data Transfer Control The coordinate data transfer control assembly
305. speech output at a data rate of 2400 bps It is capable of fill duplex or half duplex operation figure 3 36 It can be used to provide a single digitized voice circuit or have its output multiplexed with other data bit streams to provide simultaneous voice and data transmission It is used primarily as an analog to digital converter in Fleet Satellite Secure Voice communications Switching Unit SA 1704 UG The Switching Unit SA 1704 UG is used in baseband equipment shore installations of SSIXS CUDIXS and TACINTEL subsystems It is a passive patch panel that shows the equipment configuration in use Each subsystem unit is slightly different In CUDIXS the switching unit maybe used to switch in equipment from the spare system whereas in SSIXS it is used to switch in standby equipment The SB 4333 U Patching Switchboard is the planned replacement for this unit Time Division Multiplexer TD 1150 USC The TD 1150 USC time division multiplexer is installed at broadcast keying stations ashore It is used in the Fleet Satellite Broadcast subsystem and consists of two units one online and the other in standby It accepts up to fifteen 75 bps data channels and multiplexes this information into a single 1200 bps output data stream A TD 1150 USC is shown i Multiplexer DAMA TD 1271B U The Multiplexer DAMA TD 1271B U is used in the DAMA subsystem and provides time division Figure 3 36 Audio Digital Converter CV 3333 U Fi
306. stening blue Figure 5 7 The link monitor display pattern Ines REPORT ees s PHASE ems REF PREAMBLES CODE MESSAGE DATA VARIABLE LENGTH PICKE PICKET REPLY ee STOP Ll T VU TUA Ron iom f NCS CALL UP bones SE Net We Ll Le PREAMBLES Figure 5 8 Link 11 messages as displayed by the LMS 11 link monitor mode N status display consists of the status box and two lines of information just above the status box The top line with the heading XMT ADDRS displays the addresses of all PUs in the order they are being polled The operator can monitor the polling in real time The displayed addresses change colors to indicate their status If the address is yellow it is currently being interrogated The yellow address turns green when the start code is received The yellow address turns red when the PU has been interrogated twice and no response is received The line under the XMT ADDRS is used to display system messages and LMS 11 alerts Alerts are displayed on the left side of this line System messages are displayed on the right side of the line The status box provides the operator with information about signal processing link activity and raw recording of link data Just below each of the frame types a small green box or light appears to indicate the type of frame being processed These signal processing
307. stions etc Privacy Act Statement Under authority of Title 5 USC 301 information regarding your military status is requested in processing your comments and in preparing a reply This information will not be divulged without written authorization to anyone other than those within DOD for official use in determining performance NETPDTC 1550 41 Rev 4 00 Vil 1 FUNDAMENTALS INTRODUCTION Communications in general and especially in systems covers a broad spectrum from a simple single channel voice circuit to the fastest growing field of electronics satellite communications This training manual will provide you with knowledge applicable to questions and situations that arise on the job Chapter 1lis a refresher course in basic communications systems and terminology Chapters 2 and 3 will lead you through many of the systems and equipments in use today Chapter 4 will discuss the Link 11 system chapter 5 will cover the Link 11 Fault Isolation chapter 6 lwill discuss Link 4 A chapter 7 will introduce you to the new technology in data communications and the Link 16 system and chapter 8 will discuss local area networks The Electronics Technician rating is extremely diverse Many ETs never get the opportunity to work in the communications field Those who do are often locked into one particular system for many years This assignment pattern sometimes causes ETs to feel overwhelmed or lost in their career
308. submarine message traffic is input via the teletypewriter or tape reader equipment SSN submarines that have the Data Link Control System DLCS installed have an additional input output capability via the sensor interface unit SIU for over the horizon targeting OTH T messages Rf Transmission Link Control Ashore the SSIXS subsystem shares access to the same satellite rf terminal equipment as the other uhf SATCOM subsystems with the exception of COMSUBGRU SEVEN Yokosuka Japan which is equipped with dedicated AN WSC 3 transceivers Since each BCA 15 located some distance away from the Naval Computer and Telecommunications Area Master Station NCTAMS line modems and land lines are required for interconnection The submarine uhf rf terminal is the single channel half duplex AN WSC 3 SSIXS transmissions are at 4800 bps The capability to operate SSIXS in the DAMA net see the section on DAMA has been successfully demonstrated and will be used in the future Each subscriber to a SSIXS network is assigned a unique identification number that is used in all transmissions to or from the subscriber The identification numbers are stored within the shore station and subscriber processors and are used for the following purposes e At the shore stations the subscriber iden tification number when combined with broadcasts determines the number of times message traffic 15 transmitted to the subscriber When a subscriber makes a
309. t Figure 7 4 C 12428 USQ 125 Control Unit 7 4 THE JOINT TACTICAL INFORMATION DISTRIBUTION SYSTEM LINK 16 The Joint Tactical Information Distribution System Link 16 is a new tactical data link that was introduced to the fleet in 1994 Link 16 has been referred to by several names and acronyms The Tactical Digital Information Link TADIL is a term used by the U S Joint Services The TADIL designation for Link 16 is TADIL J The Joint Tactical Information Distribution System JTIDS refers to the communications component of Link 16 The communications component includes the terminal software hardware RF equipments and the waveforms they generate The NATO terms for JTIDS is the Multifunctional Information Distribution System MIDS For our purposes we will use the term Link 16 when referring to this system FEATURES OF LINK 16 Link 16 allows for the exchange of real time tactical information between units of the Navy the Joint Services and the members of NATO Although some of the functions are identical to the functions of Link 11 and Link 4A Link 16 also provides data exchange elements that the other link systems lack These include the following Nodelessness resistance Flexibility of communication operations Separate transmission and data security features Increased numbers of participants Increased data capacity Network navigation features
310. t None of the above ry GO D pL
311. t is received error free the percentage is found by comparing the number of error free message data frames with the total number of message data frames received CF This is a percentage of control code failures A PU with strong signals that never misses a call will have a 0 code failure A PU that never answers such as a dummy PU will have a 100 code failure NCS 77 PU DISPLAY PU 0 RC FAST SIDEBAND USB LSB DIV XMT ADDRS 21 16 65 70 61 LMS LSN PRE PHA En RELATIVE POWER dB 66 77 0 CC1 CC2 EOT NOIS DATA REC DATA 29 NCT 35 eee DATE 9 29 89 TIME 14 18 53 SUMMARIZE 1CYCLES PHASE ERROR DEGREES 12 39 38NP0205 Figure 5 12 The LMS 11 PU Display mode Values between 1 and 100 could be due to noise or weak equipment or an equipment malfunction BER This is the bit error rate measured as the number of bit errors per 1 000 Bit errors increase as the signal to noise ratio decreases A bit error rate that exceeds a theoretical value for a given SNR 15 indicated by displaying both the BER and SNR in yellow REL 605 This column indicates the relative power of the 605 Hz tone with respect to the average power of the 15 data tones measured in dB It should be 6 dB VAR DATA This is the variation of power in the data tones in dB The relative power of each of the data tones with respect to the average power of the data tones 1s determined The variat
312. t of status information Transmission of status data from the NCTAMS NCTS and USAF Satellite Operations Center is via teletypewriter order wire The Naval Computer and Telecommunications Command maintains a substantial quantity of updated status data in computer files A diagram of the Control Subsystem is shown in figure 3 15 5 15 S VINAVN SXIIQO Pensguoo VjNV I T ams SINSWAYINDSY WSodivdd OL SNIGHOOOV SWA1SAS JHL JO JNO HLIM S3OV3iH3lNI 2 ETV30051 3QON VINVO NI Q3Sf LON SOVINAVN 31 39 BL SdQo i ONIHOLIMS XX A v9 OSn NV 1 NV sxiano 4 OuvwoLnv l e l N ez Hn I NV SI vo osniverwo 1 99M A 90 OVW LINN TOULNOD PEON eS NOLLVOINNWNOD KI maura 83980589 i eran I i N S 29 11 i M3INRId3T31 SuVdNOOAVN 99 051 811 uOIVOIIN NE i TOULNOD senses cc CE 97 1 9351 9N S A 79 11 m E OSM 9ZE HO er YSINIddST1AL I A 2 HSN NV OHNO i ee nM 9 97 OSL NOLLVOINNWNOD lI tCoSM NY SIHdVESOLAAYD 430NODSY NSOSM 1 LL O9N NV usAmosN L 11 1 3131 li cosminy i T pisci Pa 9n Y0LIAS A 0 NV YOSSIIONd f 4 oss3oONd
313. te which of the following 1 The address of the NCS 2 The next picket address in the roll call 3 The end of the NCS message 4 The last address interrogated A picket reply message is sent in which of the following sequences 1 Preamble phase reference data stop code 2 Preamble phase reference start code data control stop code 3 Preamble phase reference start code data picket stop code 4 Phase reference start code data preamble stop code The DTS operates in full duplex when it performs which of the following operations System testing Net Test Normal operations Short Broadcast Hm CO DO Fe 3544 The DTS performs which of the following functions le Data encryption 24 Error detection and correction So Track gridlock 4 Transmitting data tones ona carrier frequency The six hamming bits added to the data word enables the DTS to correct what maximum number of data bits One Two Three Four CGO Lm The DTS 1S operating in the detect and correct mode A data word is received by the CDS computer with bit 24 0 and bit 25 l Which of the following conditions is indicated by this bit combination 1 No errors detected 2 Parity error s detected 3 Odd bit error s detected correction attempted 4 Even errors detected no correction attempted The DTS develops a composite Signal consisting of what total number of frequency division multip
314. ted in turn by NCS 4 Preamble frames diac A 3 27 When the stored sync mode is B operating the picket station Suec uses which of the following 4 D signals to establish a time base 3 22 What Link 11 operating mode provides an overall evaluation 1 An external frequency of net and equipment standard performance 2 The internal frequency standard in the DTS i iB 3 The sync signal received Zur XU fron NCS Ss D 4 The sync signal received 4 E from another picket Se In what Link 11 operating mode 3 28 Which of the following will one participating unit functions is NOT tested when transmit data continuously to Net Test is running all other net members 1 DTS to radio interface Ls C 2 CDS computer to DIS rec interface De d 3 Radio to antenna interface 4 4 Radio receiver function 3 24 In what Link 11 operating mode 3 29 The preamble of a Link 11 are the radlo set key dine message consists of a total of data terminal audio output how many frames inhibited 1 Five dac 2 OU 2 D 3 Seven Od 4 Eight 4 F 3 30 During transmission orf the ike preamble the 605 Hz tone is transmitted at which of the following power levels to 2 94 12 0B T l2 dB 3 91 Ses 35599 35 940 20598 To enable the DTS to detect 05904 frame transitions during the preamble the 2915 HZ sync tone 15 phase shifted how many degrees at each frame im 90 Be 50 Z 4 360 The phase
315. tered into the PU field then the data display is continuously updated with samples from the entire net Carrier Suppression Display The carrier suppression display measures how successfully the carrier frequency is suppressed The carrier suppression measurements can only be made during Net Sync To measure the carrier suppression the radio must be off tuned by 500 Hz for the upper sideband and 500 Hz for the lower sideband This off tuning allows the program to measure and compare the relative power of the carrier frequency and the 605 Hz tone of the preamble XMT ADDRS 2002 14 06 41 22 31 43 12 24 32 36 36 16 10 04 30 23 15 21 11 LMS LSN PRE PHA _ 1 CC2 EOT NOIS DATA REC DATA 12 6 9 NI E NCS 11 SPECTRUM DISPLAY DATE 4 3 87 RC FAST TIME 8 21 23 SIDEBAND USB LSB DIV RESTRICT NONE PREAMBLE DATA PU 2 REL POWER 00 mm 5 E TTT IMS Nl T IHE dl i 3 E FRR 0 NEN 3 11 nin 01 03 05 07 09 11 13 15 17 19 21 23 25 27 29 TONES RECOGNIZING LINK 11 NET PROBLEMS The LMS 11 is very useful in evaluating Link 11 net quality As you have seen the various on line modes can help you determine various problems These include a station that is consistently missing call ups poor signal to noise ratio and low power from a unit Some common Link 11 problems a
316. the OWN STATION ADDRESS switches perform which of the following DTS functions 1 Transmits the entered address to all other members of the net 2 Transmits the entered address to NCS only 3 Receives messages that match the entered address 4 Transmits tactical data when the interrogation message address matches the entered address On the NCS platform operating in a Link 11 net where the units are approximately 100 miles apart which of the following values should be entered into the RANGE IN MILES Switches 0 miles 2 25 miles R 50 miles 4 100 miles With a single address control Sas indicator dn plattorm control what maximum number of participating Unies due uj 2 00 D SO 4 20 Data exchange between the DiS and Ehe CDS computer is controlled by the Od 93 DTS using which of the Following control signal protocols 1 External interrupts 2 External functions 3 Input data requests 4 Output data requests During a receive data cycle the DTS performs which of the following actions when frame two of the stop code 15 3 74 detected 1 The frame is processed as a data frame and sent to the computer 2 The DTS processes the stop code and resets itself only 3 The DTS sends the end of receive external interrupt to the computer 4 The computer processes the stop code and closes the input data buffer Which of the following actions Sea or is performed by the DTS when a control
317. the computer the software accesses them as if they were external disk drives The AN USQ 69 V data terminal set 15 used to provide the man machine interface MMI It is installed next to the Track Supervisor in CIC Several equipments are shared between the ACDS system and the C2P system These include the magnetic tape unit a teleprinter and a second AN USQ 69 V data terminal set The magnetic tape unit is used for initial program loading to EMS data extraction and reading and writing JTIDS information to and from tape It 1s also a backup load device when the EMS is down The teleprinter provides hard copy printouts of C2P system status error codes and data dumps The second AN USQ 69 V is used as a backup Shared equipments are switched to the desired systems through the Combat Systems Switchboard The switchboard also provides switches to connect Link 4A and Link 11 directly to the CDS computer bypassing the C2P system CHAPTER 8 LOCAL AREA NETWORKS INTRODUCTION A local area network LAN is a communications system designed to transmit and receive digital information between computers A LAN consists of nodes that are interconnected by links Nodes are the hardware connected to the network such as personal or microcomputers printers large capacity hard drives and so on Links are the communications media such as twisted pair wire coaxial or fiber optic cables that connect the nodes In most applications the LA
318. tion is obtained by which of the following methods 1 Use of the frame timing reference stored during Net oync 2 Use of the frame timing reference obtained from the preamble of the current message only 3 Use of the frame timing reference obtained at each data frame of the current message only 4 Use of both the frame timing reference obtained during the preamble and the frame timing of each frame of the currenur message The NET BUSY indicator of the TADIL A control panel is activated by which of the following signals Signal presence Receive mode Transmit mode Start code detected gt CO Ihe SYNC COMPT andicator 1s lighted after the DTS has achieved which of the following conditions 1 It is in sync with the radio 2 It is using stored SVHhoOhromizocqgom Signals Jb XS Xn Syne with NCS 4 It is testing the internal Sync Circuits 9e ds The TIMING STORED CORRECTED 3 64 switch is set to the STORED position Which of the following signals will the DTS use for frame timing synohronizatlone 1 The frame timing reference stored during Net Sync 2 The frame timing reference obtained from the preamble of the current message only 3 The frame timing reference obtained at each data frame of the current message only 4 Both the frame timing reference obtained during the preamble and the frame IOI timing of each frame of the message When the ERROR CORRECT LABEL
319. tions and control and 2 quality monitoring subsystems that provide data required to manage satellite resources Each subsystem is structured for specific naval communications requirements The following subsystems make up most of the Navy s FLTSATCOM system Fleet Satellite Broadcast Subsystem This is an expansion of the Fleet Broadcast which has been the central communications medium for operating naval units Common User Digital Information Exchange Subsystem CUDIXS and Navy Modular Automated Communications Subsystem NAVMACS These two installations form a communications network for transmitting general service message traffic between ships and shore installations Submarine Satellite Information Exchange Subsystem SSIXS This subsystem compliments other communications links between SSBN and SSN submarines and shore terminals e Secure Voice Subsystem This is a narrowband uhf subsystem that links voice communications between ships and connects with wide area shore voice networks 3 3 Tactical Intelligence Subsystem TACINTEL This subsystem is specifically designed for special intelligence communications Teletypewriter Subsystem This subsystem is an extension of terrestrial teletypewriter transmission networks Tactical Data Information Exchange Subsystem TADIXS This is a one way broadcast of tactical information from command centers ashore to afloat units primarily in support of
320. tions refers to com munications over a distance and includes any 1 1 transmission emission or reception of signals writing images and sounds Intelligence produced by visual or oral means or by wire radio or other electro magnetic systems is also included Electrical visual and sound telecommunications are all used by the Navy In this volume we will discuss electrical types of telecommunications COMMUNICATIONS SYSTEMS A communications system consists of two or more units each having its own separate identity arranged and interconnected to perform a circuit operation that cannot be performed by one of the individual units alone Navy communications systems vary from sim ple to very complex depending upon the circuit opera tions involved Each system requires the integrated use of various types of equipment so flexibility is of the ut most importance This flexibility 15 provided through complex arrangement of interconnections that allow the physically separated sets groups and units to be selectively switched patched into the different circuit configurations Most shipboard communication equipments do not operate independently A particular piece of elec tronic gear may be designated primary and still be used in many different system operations You need to understand all the associated equipment in a system to identify problems correctly and to make repairs promptly Thorough knowledge of system operati
321. tive motion between the transmitter and the receiver It 15 also used to correct for the Doppler shift that may occur because of differences between the transmitter and receiver frequency standards The 2 915 Hz tone has two separate uses During the transmission of the preamble and Net Sync the 2 915 Hz tone is used to identify frame timing This tone is phase shifted 180 degrees at the end of each frame When detected by the receiving DTS the phase shift indicates the start of a new frame When the DTS is in corrected timing this information is used to set the timing for the data frames that follow When stored timing is used the frame timing that was set during Net Sync 15 used The Doppler and sync tones vary from each other and the other data carrying tones in amplitude The Doppler tone is 6 dB greater than the other tones During the Net Sync and preamble frames the Doppler tone is transmitted at 12 dB and the sync tone is transmitted at 6 dB The Doppler tone is transmitted at 6 dB during the transmission of data frames and the sync tone is used as a data tone Data tones are transmitted at O dB The audio tones are divided into data frames to identify the separate parallel groupings of 30 bits It is the phase angle shift of each of the 15 data tones that conveys the digital information contained in the tone During each frame each data tone frequency has a particular phase At each frame boundary the phase of each data to
322. tones are the same as described i Message formats and modes are also the same Single Tone Waveform Link Single tone waveform link updates the 1960 s technology used in data communications The single ton waveform is a 1 800 Hz phase modulated waveform containing the Link 11 data in a serial bit stream The single tone waveform is most commonly used with the wire line option of the USQ 125 data terminal The CP 2205 P V USQ 125 data terminal wire line option provides an interface port that can be used with a standard wire line or a satellite modem Using this option expands the means in which Link 11 data can be exchanged overcoming the limitations of the traditional UHF and HF radio links Enhanced Link Quality Analysis ELQA The Enhanced Link Quality Analysis option of the data terminal incorporates almost all of the functions of the LMS 11 This allows the operator to monitor and evaluate the performance of the link net Information that can be displayed includes the following sideband power error rate and percentage of interrogations answered Maximum Useable Frequency MUF Option The maximum useable frequency option is a routine that calculates the optimum frequency for Link 11 operations This routine calculates frequency for each hour of the day based on geographic location the range of other participants in the net and sunspot activity Multi Frequency Link The multi frequency link option improves curr
323. transmission to the shore station the identification number is included The shore station will not acknowledge a transmission without receiving the identification number e The subscriber uses the number to screen incoming message traffic Any data that is not addressed to that particular subscriber is discarded SECURE VOICE SUBSYSTEM The Secure Voice subsystem enables the transmission of ship to ship ship to shore and shore to ship voice communications via satellite relay Figure 3 7 shows a Secure Voice subsystem AUTOSEVOCOM has been replaced by radio wireline interface RWI at all NCTAMS shore activities The subsystem transmits and or receives secure voice communications via a half duplex push to talk satellite link Channels on each of the four FLTSATCOM satellites have been allocated for use by the Secure Voice subsystem Control of the voice channels is maintained by the Secure Voice controller at the responsible NCTAMS NCTS The subsystem uses digitized voice at a data rate low enough to be compatible with a 3 kHz voice channel and is considered narrowband The sound of Narrowband Secure Voice is very distinctive Once you hear it you won t forget it The system uses special analog to digital processing of the speech signal at the handset terminal and the rf transmission rate 1s 2400 bps The Secure Voice subsystem has dedicated rf channels on the uhf SATCOM satellites as well as dedicated DAMA time slots where
324. transmit side of the transceiver through the transmitter transfer switchboard The audio tone shift signals are then used to modulate the rf carrier for transmission AFTS Receive The rf tone modulated signals are received at the antenna and then patched via the multicoupler to the receive side of the transceiver where demodulation to audio tone shift signals takes place The signals are then patched to the tone terminal set through the re ceiver transfer switchboard where they are converted back to dc signals The dc signals are then patched through the communication patch panel to the tty FACSIMILE Facsimile FAX is a method of transmitting still images over a communications system The images may be weather maps photographs sketches typewritten or printed text or handwriting Military 2 23 use of FAS is primarily limited to transmission and reception of weather maps Because of long transmission times its tactical uses are limited TEMPEST Compromising emanations generally called TEMPEST are unintentional data related or intelligence bearing signals which if intercepted or analyzed can disclose the classified information transmitted received handled or otherwise processed by electrical information processing equipment or systems The Navy uses MIL STD 1680 SHIPS Installation Criteria for Shipboard Secure Electrical Processing Systems as the guide for TEMPEST Within communications centers ETs must u
325. tware and the central processing and storage point of the application software and data files of the network The file server has a hard disk with a very large storage capacity The file server manages the hard disk and ensures that multiple requests for the same file do not conflict with each other In the disk server environment each PC workstation manages its I O with the disk through low level sector calls In the file server environment each workstation communicates with the central disk through the use of high level calls to the file server A high level call can be a request to open a particular file or to store a file while a low level call maybe to write this file to sector xyz on the disk The file server converts the high level calls from the users to low level disk commands thus providing effective disk management The file server maintains the list of privileges and authorizations for each user This protects the data files from unauthorized access and protects the data An example of this is that one user may be authorized total access to a data base file to update the file while another user may be authorized read only access to the information Still a third user may be denied access to the file altogether A network file server is a special purpose unit that can reside in either a dedicated computer or one of the workstations a PC that has a hard disk containing the software of the network When the network server is
326. uadrature phase shift modulation 2 Frequency modulation 3 Phase modulation 4 Amplitude modulation independent sideband Which of the following individuals is responsible for assigning primary and secondary Link 11 frequencies before the deployment of a task force 1 The aircraft carrier commanding officer 2 The net control station track supervisor 3 The task force commander 4 The fleet CinC When a Link 11 net is established which of the following sequences of operations should be followed to determine readiness of all units to enter the net 1 Net Test Net Sync roll call 2 Net Sync Net Test roll 3 Net Sync Net Test Broadcast 4 Roll call Net Test Net sync Net Synchronization Short Broadcast Radio Silence A Ds Net Test Us ROLL Call Broadcast E F Figure 3B IN ANSWERING QUESTIONS 3 20 THROUGH 3 25 In what Link 11 operating mode 3 259 SELECT EROM PIGUBE OB THE is a single data transmission OPERATING MODE DESCRIBED IN THE sent only when the operator QUESTION depresses the TRANSMIT START button 3 20 What Link 11 operating mode establishes a uniform time base Ls B from which all net Bo C communications are normally 3u D initiated 4 E 1 3 26 Net Sync continuously 2 B broadcasts which of the 6 following signals a D 1 Phase reference frames 3 21 In what Link 11 operating mode codes is each picket unit 3 Stop code interroga
327. ual 200 watts It s important to understand that no matter how much power is involved a loss or gain of 3 dB always represents a halving or doubling of the output power Technically the dB level of a signal is a logarith mic comparison between the input and output signals shows the common logarithms used to calcu late dB Normally the input signal is used as a refer ence However sometimes a standard reference signal is used The most widely used reference level is a 1 milliwatt signal Decibels measured in reference to 1 milliwatt are abbreviated dBm A signal level of 3 dBm is 3 dB above 1 milliwatt and a level of 3dBm is 3 dB below 1 milliwatt The formula for dBm is a varia tion of the dB power formula dim i0log actual power P2 001 watt P1 As a Navy technician you will use the dBm system of measurement often to perform receiver sensitivity tests For example a receiver rated at 110 dBm will detect a signal 110 dB below 1 milliwatt Suppose the LI L R AA YID IF STRIP ALININ AMPLIFIER MIXER DETECTOR gt A FILTERS p LL B ERN JD LOCAL HF AFC CARRIER La OSCILLATOR IRCUITS REINSERTION OSCILLATOR ETV30000 Figure 1 9 Basic ssb receiver 1 10 Table 1 3 Decibel to Power Ratio DB Loss or Gain Power Ratio Loss or Gain e UO O C C
328. unications relay between locations in congested areas and antenna farms TROPOSPHERIC SCATTER SYSTEM At microwave frequencies the atmosphere has a scattering effect on electromagnetic fields that allows for over the horizon communications This type of communications is called tropospheric scatter or troposcatter for short Troposcatter takes place mostly at low altitudes but some effect takes place at altitudes of up to 10 miles Under the right conditions troposcatter can take place over hundreds of miles A tropospheric scatter microwave system consists of one or more point to point hops or sections Each hop is designed so it can be integrated into the worldwide communications network of the Defense Communications System DCS Troposcatter links have the following characteristics e Propagation Free space as affected by the tro posphere e Communications capacity bandwidth Up to 600 4 kHz voice channels wideband can accept TV e Range Up to 800 km 500 statute miles e RF Power High up to 75 kilowatts depending upon bandwidth quality and range Coverage Point to point only e Antennas Both transmitting and receiving antennas are horn driven paraboloids providing high gain and narrow beam widths e Reliability Designed to be operational more than 99 of the time including periods of poor propa gation 2 13 e Countermeasures Extremely difficult to jam Should not be suscepti
329. unit 1 One aS NCS unm s 2 Two net to improve net 3 Five communications 4 Six 1 The current NCS has one PU 4 4 The EDAC bits enable the DTS to address entered wrong correct a total of how many 2 Ine current NCS has received bit errors receiver sensitivity and 15 POLI EG Om Top o mU responses 2 Two 3 Several PUs are a 3 Three propagation shadow 4 Four 4 Several PUS are out of range of the current NCS unit 4 9 Changing frequencies will always solve Link 11 problems 1 True 2 False t9 When you keep the radio set 4 14 tuned to output maximum power it causes which of the following problems 1 Increases RFI EMI on transmitting unit 2 Increases receive data errors on receiving units by saturating the data terminal sets only 4 15 3 Increases RFI EMI on the transmitting unit and increases receive data errors by DTS saturation 4 Decreases RFI EMI on the receiving units When the NCS enters dummy PUs which of the following net condicions will eGxrst Xf any 4 16 1 Net efficiency increases 2 Net cycle time decreases 3 Net cycle time increases 4 None dummy PUs have no effect on the net What following NCS action is the most effective net management technique when a PU is having trouble maintaining Link 11 Communications Iy Continuing normal 4 17 operations the trouble PU 2 Directing the PU to go to radio silence
330. unting of one C 9597 WSC 1 V antenna control one C 10232 WSC 3 and up to four RT 1107 WSC 3s These racks contain all the wiring required to interconnect these items Connectors installed on the top panel provide system interface connections for baseband teletype frequency standard external modem and control indicator equipment The C 9597 WSC 1 V antenna controller provides a means of controlling the antennas in the OE 82 dual 535 e IE Oo e D 3 C 9597 WSC 1 V Jm 4 x T T mo x 4 2 C 10232 NSC 3 RT 1107AVSC 3 qe T b toe B RT 1107AVSC 3 m dovete C RT 1107AVSC 3 E A o RT 1107ANSC 3 ETV30078 Figure 3 40 Electrical Equipment Rack CY 7597 WSC 3 shipboard system The control indicator 3 34 can switch the AN WSC 3s for LOS or SATCOM use monitor rf output power and provide power on off switching Electrical Equipment Cabinet CY 7971 WSC The CY 7971 WSC fig 3 41 provides for mounting one MX 10342 WSC two SB 4124 WSCs and two TD 1271B U multiplexer The cabinet contains all wiring required to interconnect these pieces of equipment Connectors installed on the top panel provide system interface connections for baseband teletype frequency standard AN WSC 3 and control indicator equipment The MX 103
331. urse we encourage you if possible to use e mail If you write or fax please use a copy of the Student Comment form that follows this page For subject matter questions E mail n315 products cnet navy mil Phone Comm 850 452 1001 Ext 1713 DSN 922 1001 Ext 1713 FAX 850 452 1370 Do not fax answer sheets Address COMMANDING OFFICER NETPDTC N315 6490 SAUFLEY FIELD ROAD PENSACOLA FL 32509 5237 For enrollment shipping grading or completion letter questions E mail fleetservices cnet navy mil Phone Toll Free 877 264 8583 Comm 850 452 1511 1181 1859 DSN 922 1511 1181 1859 FAX 850 452 1370 Do not fax answer sheets Address COMMANDING OFFICER NETPDTC N331 6490 SAUFLEY FIELD ROAD PENSACOLA FL 32559 5000 NAVAL RESERVE RETIREMENT CREDIT If you are a member of the Naval Reserve you may earn retirement points for successfully completing this course if authorized under current directives governing retirement of Naval Reserve personnel For Naval Reserve retire ment this course is evaluated at 9 points Refer to Administrative Procedures for Naval Reservists on Inactive Duty BUPERSINST 1001 39 for more information about retirement points Student Comments Course Title Electronics Technician Volume 3 Communications Systems NAVEDTRA 14088 Date We need some information about you Rate Rank and Name SSN Command Unit Street Address City State FPO Zip Your comments sugge
332. ver twisted pair cable If buildings are already wired with twisted pair cable meeting AT amp T premise cabling specifications STARLAN can be installed easily It is considered to be a low cost per user network and its star topology makes it a flexible network ARCnet ARCnet is a distributed star topology that uses a token passing protocol and either twisted pair or coaxial cabling Its throughput speed is 2 5Mb per second Although ARCnet does not conform to an IEEE standard it closely resembles the 802 4 standard for a token bus system It can easily handle up to 75 users If user demand is low it can handle additional users It is considered an extremely reliable network and it 1s easy to install expand and modify IBM Token Ring Network The IBM Token Ring Network uses a star ring topology and is defined by the IEEE 802 5 specification It has a throughput speed of 4 Mbits per second and 16 Mbit per second This allows for flexible expansion of very large networks Because of its speed and token passing protocol it is a good choice to meet high volume requirements It is a sophisticated LAN technology developed by IBM to be used with an IBM cabling system and it 1s currently the fastest growing installed network base The star ring topology also makes use of redundant circuits and loopbacks to handle breaks in the ring and results in high fault tolerance on the network NETWORK OPERATING SYSTEMS Network operating system softw
333. we have seen the operation and maintenance of a high quality link can be affected by many factors For years operators and technicians commonly blamed each other for poor link operations Some typical Link 11 problems are as follows Participating units PUs not responding to call ups Garbled data The link goes completely dead normal Operation ceases Inability to establish a net Excessive net cycle time When such a problem occurred the Link 11 technician would run a single station POFA and declare that the DTS was sound and it must be the other ship a poor frequency or an operator error The operator would blame the frequency or NCS Other units would say the problem was another platform jamming the entire net Typical strategies used to solve link problems usually began with a recommendation to change frequency When this strategy failed to solve the problem the next step was to change NCS If the problem still existed then NCS would eliminate PUs from the net one at a time until the problem unit was identified All of these actions took time and were hit and miss techniques This tendency of trial and error troubleshooting and pointing fingers defined the need for a reliable visual system of monitoring the Link 11 network This need was filled with the development of the Link Monitoring System AN TSQ 162 V 1 commonly called the LMS 11 The LMS 11 provides an operator or a technician with a real ti
334. wing colors 1 Yellow 2 Red yan 4 Green 4 55 An NCS report can be easily identified on the link monitor display by which of the following features 1 A two digit address at the end of a report only 2 No call up message between the end of the preceding report and the NCS report OnLy 3 Both a two digit address at the end of the report and no call up message between the preceding report and the NCS report 4 A call message to the NCS 4 56 address An address shown in red on the XMT ADDRS line of the status display indicates which of the Following Conditions 1 The addressed unit is being interrogated 2 The addressed unit failed to answer two interrogations 3 The addressed unit has replied to an interrogation 4 The unit indicated is the next address in the polling sequence 24 When the LMS 11 is operating in the link monitor mode and a phase reference frame is detected which of the FOLLOWING 9 active CCa PHA PRE EOT A w N e When the LMS 11 is operating in the link monitor mode and the first frame of a picket stop code is detected which of the following status indicators is active b iC 2 PHA PRE 4 EOT Im Che status oox The number in the DATA indicates which of the following quantities 1 The total percentage of data in the last message received 2 The percentage of data that 15 error free in the last message received 3 The total per
335. wing them to overcome the problem ANCILLARY EQUIPMENT Now that we have looked at the basic components of a communications system let s identify some of the ancillary equipment required to make a transmitter and receiver useful HANDSET A handset converts acoustical sound energy into electrical energy which is used to modulate a transmit ter It also converts electrical energy into acoustical en ergy for the reproduction of the received signal To key a transmitter the push to talk button is de pressed closing the dc keying circuit which places the transmitter on the air The handset is normally con nected to a radio set control but can be used locally at the transmitter Using the local option is a good way to determine whether a problem exists in the transmit ter or remote equipment RADIO SET CONTROL The radio set control provides the capability to control certain transmitter functions and the receiver output from a remote location Some control units con tain circuits for turning the transmitter on and off voice modulating the transmission keying when using CW controlling receiver output and muting the re ceiver when transmitting A representative radio set control unit is shown in figure 1 10 As many as four of these units maybe par alleled to a single transmitter receiver group to provide additional operating positions This setup is often found aboard ship when a transmitter or receiver 15 cont
336. work security has not been breached The main disadvantage of the star topology is its reliance on the central computer for performing almost all the functions of the network When the central computer fails all nodes also stop functioning resulting in failure of the entire network DISTRIBUTED STAR The distributed star or tree topology is shown in It provides many of the advantages of both bus and star topologies It connects workstations to a central point called a hub This hub can support several workstations or hubs which in turn can support other workstations Distributed star topologies can be easily adapted to the physical arrangement of the facility site If the site has a high concentration of workstations in a given area the system can be configured to more closely resemble a star topology If the workstations are widely dispersed the system can use inexpensive hubs with long runs of shared cable between hubs similar to the bus topology RING NETWORK In a ring network all the components or nodes are connected to the main cable and the cable forms a ring as shown in This topology allows a node to send a message to another node on the ring NETWORK SERVER 38NP0189 Figure 8 5 A ring network topology However the message must be transmitted through each node until it reaches its destination Messages proceed from node to node in one direction only Should a node fail on the network data can no long
337. xamples of low cost systems are STARLAN ARCnet 10Net and LANtastic Zero Slot Network Operating Systems Zero slot network operating systems are appropriate only for networks with very few users and Light usage They are an inexpensive and simple alternative to the NOSs that require expensive network interface cards Rather than requiring each workstation computer to have a NIC the computer s RS 232 serial communications port twisted pair cables are used Because of this they are very slow and offer limited file transfer abilities They may not provide disk sharing An example of a zero slot system is LANLink APPENDIX LIST OF ACRONYMS ACDS advanced combat direction system ACRO or CRO auxiliary cathode readout ALT key alternate key A N alphanumeric APA all points addressable AM amplitude modulation ASCII American Standard Code for Information Interchange ASTAB automated board status ASW antisubmarine warfare BC broadcast BDU basic display unit BER bit error rate BITE built in test equipment BPS bits per second C2P Command and Control Processor CAG central automated status board generator CCAEP computer controlled action entry panel CDB central data buffer C DITEG common digital television graphics generator CDS combat direction system CED console electronic drawer CEG central equipment group CGA c
338. xtract the original intelligence Terminal equipment is used primarily to convert the audio signals of encoded or data transmission into the original intelligence A basic radio communications system may consist of only a transmitter and a receiver connected by the medium through which the electromagnetic waves travel see figure 1 1 The transmitting equipment creates a radio frequency rf carrier and modulates it with audio intelligence to produce an rf signal This rf signal is amplified and fed to the transmitting antenna which converts it to electromagnetic energy for propa gation The receiving antenna converts the portion of the electromagnetic wave it receives into a flow of alter nating rf currents The receiver then converts these currents into the intelligence that was contained in the transmission Terminal equipment is used primarily where coded transmissions are employed to convert the modulated signal into the original intelligence Sys tems you will encounter in the fleet use terminal equip ment such as AN URA 17 and CV 2460 THE FREQUENCY SPECTRUM Figure 1 2 shows the overall electromagnetic fre quency spectrum as defined by the International Tele communications Union Pay particular attention to the part used for communications Rapid growth in the quantity and complexity of communications equip ment and increased worldwide international require ments for radio frequencies have placed
339. y PU 04 s of line two Next PU 56 is called and responds with reply PU response on the left side a picket reply Upon completion of PU 56 s 64 is called After 15 frame times without a response PU 64 is called again PU 64 appears to have responded to the second call but the LMS 11 only recognized the five preamble frames By using the link monitor display the operator or technician can make sure the connectivity has been established and that all the correct PUs are being polled and are responding Figure 5 6 also shows several problems that commonly occur during Link 11 operations Notice that PU 64 sometimes responds to the first call up sometimes to the second call up and sometimes PU 64 does not respond at all PU 56 responds all the time except for the call up at the end of line two and beginning of line three On line six there is a double response or echo from PU 04 If you were to examine this particular sequence using the frame by frame analysis you would find the PU 04 was called again This indicates the NCS did not receive the report from PU 04 and repeated the call up during the middle of the response Status Display As shown in figure 5 9 the status display is at the bottom of each of the LMS 11 display screens The Level 0 Listening blue 1 Preamble yellow 2 Phase Ref green 3 Control Code start red 3 Control Code stop red 3 Control Code address red 6 PU Number red 0 Li
340. y a specific communications requirement Further as the following paragraphs explain a system is a combination of sets units assemblies subassemblies and parts The requirement placed on the system could be to send or receive voice cw or teletype information Figure 2 1 illustrates the equipment included in a typical system to meet these communication requirements SET A SET consists of a unit or units and the assemblies subassemblies and parts connected to perform a specific function Two examples are radio receiving sets and radio transmitting sets GROUP A GROUP 15 a collection of units assemblies subassemblies and parts that 1 is a subdivision of a set or system and 2 cannot perform a complete operational function A good example is an antenna coupler group UNIT A UNIT is a combination of parts subassemblies and assemblies mounted together that can normally TELETYPE POWER SUPPLY QUT d TELETYPE N7 PATCH PANEL Y TELETYPEWRITER SERN HEADSET 6 TRANSMITTER SWITCHBOARD operate independently of other equipment An example of a unit is the power supply ASSEMBLY SUBASSEMBLY An ASSEMBLY is a combination of two or more subassemblies joined to perform a specific function A SUBASSEMBLY consists of two or more parts that form a portion of an assembly It can be replaced as a whole but some of its parts can be replaced individually The distinction between an assembly and a
341. ying limiter FM receivers have some advantages over AM re ceivers During normal reception FM signals are static free while AM is subject to cracking noise and whistles Also FM provides a much more realistic reproduction of sound because of the increased number of sidebands WIDE BAND ETV30008 DISCRIM F 24 INATOR Figure 1 8 FM superheterodyne receiver and waveforms SINGLE SIDEBAND SSB Figure 1 9 is a block diagram of a basic ssb re ceiver Though the ssb receiver is not significantly dif ferent from a conventional AM superheterodyne receiver it must use a special type of detector and rier reinsertion oscillator The oscillators in a ssb re ceiver must be extremely stable In some cases a frequency stability of plus or minus 2 hertz is required You can see that frequency stability is the most impor tant factor of ssb equipment Ssb receivers may use additional circuits that en hance frequency stability improve image rejection provide automatic gain control age However the circuits shown in figure l 5 will be found in all single sideband receivers AMPLIFICATION Because the incoming signal may be weak and be cause a certain minimum voltage level 15 required for the auxiliary equipment to operate considerable am plification must take place before the receiver output 1s used to drive speakers headphones or terminal equip ment This is usually called the gain of the r
342. ystem designed to be permanently installed 1 True 2 False The DPG and CDG equipment cases of the LMS 11 provide isolation from which of the following 4 31 environmental forces 1 Shock only 2v Vibration only je Shock and vibration 4 Power surges The LMS 11 system printer is part of which of the following equipment groups 1 Accessory 2 7 sp ley 3 Data processing ie DUDDOEL 4 38 Which of the following components is NOT part of the LMS 11 data processing group l processing Unit 2 Wiel drisk drive unit 3 Audio interface unit 4 Power control unit The HP9920U computer of the LMS 11 contains what amount of random access memory RAM 1 2 MB 2 4 MB 3 8 MB 4 12 MB 22 The data communications interface of the LMS 11 provides which of the following tunctrons 1 Parallel synchronous interface with the Link 11 data terminal 4 Parallel asynchronous interface with the printer 3 Serial synchronous interface with the Link 11 data terminal 4 Serial asynchronous interface with the printer Ihe audio interface unit of the LMS 11 connects which of the following signals USB from HE radios only LSB from HF radios only USB from UHF radios only USB and LSB from radios and USB from UHF radios H CG N Fe To determine the phase shift of the Link 11 audio tones the LMS 11 uses which of the following methods Fast Fourier Transform f

Download Pdf Manuals

Related Search

Related Contents

User Manual Windows - Mind Map with iMindQ  Philips PET721C/12 User's Manual  Chapter 11, Programmable Timers and I/O Ports    Manuale dell`utente Ammortizzatori posteriori 2002  ARCTIC SOUND P131  exquis mots 4  CL2Y8- TP1C2V CC- Link/ LT Remote I/ O Module User`s Manual  Frigidaire FFFH17F4QT Wiring diagram  BoConcept Seca Assembly Instruction  

Copyright © All rights reserved. Failed to retrieve file