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AMPLIFIER RESEARCH 20T4G18 Operating

1. 11 3 4 Front Panel Display and Soft Keys asas 12 3 5 Rear Panel Features ue dte park Rn Id hir e eres 16 3 6 Initial Turn On and Warm up Procedure 16 3 7 Emergency Bypass Operation eene 17 3 8 Remote IEEE 488 Operation nennen 4 18 3 9 TWTA General Considerations ener 23 ESA raro 25 4 1 Safety Warning n unn Alana eed RENS 25 4 2 Unauthorized Repairs i 25 4 3 Preventive Maintenance 25 4 4 Troubleshooting n 26 4 5 Non Repairable ere rente renerne renser nes 27 5 TECHNICAL DOCUMENTATTION 29 Top Level Build 30 5 2 Schematics a sace cech eie AAA ei 31 5 3 Waring ani 33 Sid Parts Tests u nasa ae a ANA OV AVE Imi ed aS 35 5 4 1 Parts List Logic and Control Module 16485 000 36 5 4 2 Parts List Power Supply Short For TWT 5172 23720 099 38 5 4 3 Parts List Emergency Bypass Board A24830 0
2. s N 6 E va 58 A Figure 3 4 Rear Panel Features Table 2 TWTA Rear Panel Features Item Title Function 1 AC POWER IN AC power input connector IEC 320 connector 2 IEEE 488 Remote control connector 24 pin hermaphrodite 3 EXTERNAL INTERLOCK Connector to remote temperature switch protecting the isolator load D sub 15 pin female 4 Cooling air intake 5 Cooling air outlet 6 RF INPUT RF input N female connector 7 FORWARD SAMPLE RF sample type N female 8 REVERSE SAMPLE RF sample type N female OPTIONAL 9 RF OUTPUT RF output TNC female connector 3 6 INITIAL TURN AND WARM UP PROCEDURE Install the TWTA as discussed in section 3 2 Provide an RF generator to the RF input Type N connector Set RF generator level below 50 dBm and set desired frequency in specified range Connect a load suitable for 100 watts continuous operation to the output waveguide The load VSWR should be less than 2 0 1 A power meter and suitable attenuators may be connected to the RF sample port A1J2 Refer to RF sample port calibration factors on the rear of the unit or on the nfo screen in MENU 2 These show the relation between the amplifier output power and the RF sample port power as a function of frequency When only the power of the fundamental frequency is to be measured and when operating near rated power use filters a frequency selective receiver or a spectrum analyzer to reduce the harmonic content of the measured level
3. 20129 000 20130 000 20279 000 20284 000 20476 000 24814 000 J17264 000 J18160 000 Model 20T4G18 DESCRIPTION CABLE RF FLEX 7 SMA MALE TO MALE 20 GHZ 50 OHM BLUE FEP TEFLON DICAR EZ402 2121 07 CABLE RF FLEX 9 SMA MALE TO MALE 20 GHZ 50 0 141 CABLE INSULATED JACKET SRC 150 150 150090 CABLE RF FLEX 12 SMA MALE TO MALE 20 GHZ 50 0 141 CABLE INSULATED JACKET SRC 150 150 150120 CABLE RF FLEX 15 SMA MALE TO MALE 20 GHZ 50 OHM 0 141 CABLE INSULATED JACKET SRC 150 150 150150 CABLE RF FLEX 20 SMA MALE TO MALE 20 GHZ 50 OHM 0 141 CABLE INSULATED JACKET SRC 150 150 150200 SSPA 4 18 GHZ 18DBM 20DB GAIN WITH 35DB VGA CPI CMA40180A XX TWT 4 18 GHZ 25 WATTS ICPI VTM 6196R5 ATTENUATOR 6DB SMA 2W SUB MINIATURE INMET 18A 6 ATTENUATOR 3DB 2W DC 18GHZ MINITURE MIDISCO MDC1065R 3 COUPLER 10DB 4 18GHZ SMA MAC TECHNOLOGIES C4258 10 ADAPTER SMA MALE TO SMA FEMALE RIGHT ANGLE CDI 5490CCSF PASTERNACK PE9262 EQUALIZER 4 18 GHZ 0 20 DB 11 GHZ SMA INMET EQ1734 ZERO BIAS SCHOTTKY DETECTOR 10MHZ 18 5GHZ POSITIVE OUT PUT POLARITY RLC M 3747 RF CABLE 18 LONG 0 290 DIA TNC SP TO SMA RAP STORM 90 1343 018 DUAL COUPLER 4 2 18GHZ PTNC 35DB 35DB MAC TECHNOLOGY CA1158 35B ADAPTER TYPE N FEMALE TO SMA FEMALE PANEL MOUNT ASTROLAB 29047 CONN 1 PIN FEMALE 20KV 10A 0 180 DIA LEAD CONNECTRONICS 11039 02 Parts List Microwave Power Assembly AR A
4. WARNING Service work must be performed only by technicians thoroughly familiar with the high voltages present in microwave tube amplifiers in general and with this eguipment in particular Never handle the TWT leads or the high voltage connectors unless it has been positively established that the high voltage filter capacitors have been discharged to a known safe level CAUTION A malfunctioning power supply can cause damage to the TWT If you are troubleshooting the TWTA remove the TWT and substitute suitable loads to prevent damage to the TWT 4 2 UNAUTHORIZED REPAIRS CAUTION Unauthorized repairs or modification of this product during the warranty A period may void the warranty In the event that the TWTA malfunetions while it is still under warranty always contact an authorized service representative 4 3 PREVENTIVE MAINTENANCE The RF characteristics and power supply voltages and currents of the TWTA should be logged on a regular basis Maintenance should be performed if significant deviations from the logged values appear If the unit is under warranty contact an authorized service representative if impaired performance is suspected If there is accumulated dust on the air intake grill clean it with dry compressed air If significant dust has been noted on the air intake grill it may be desirable to vacuum the dust and debris from inside the enclosure Rev B 25 Model 20T4G18 To open the enclosure 1 Rem
5. 16 Rev B Model 20T4G18 Set keylock to LOCAL Switch on the MAIN POWER circuit breaker The fan will operate The front panel display will show several identification messages and then the MENU 1 screen The third line will indicate that the heater time delay is active Allow the heater warm up delay to expire Line three will indicate OFF READY Push S4 MORE three times to go to MENU 4 Verify that the heater voltage and current are near their nominal levels The values of these parameters at the time the TWTA left the factory are logged on the test data sheet Push the OPERATE push button You will now see the cathode and the collector voltages rise Verify that the collector and cathode voltages are near nominal The helix current should be close to the nominal value for no drive Then push MORE or EXIT to go back to MENU 1 Set the TWTA gain to maximum Adjust the RF generator to slowly increase the RF drive toward 0 dBm to reach the desired FWD PWR on the display and power meter connected to sample port The forward power bar graph will become active with maximum length when peak power output is achieved Best performance is obtained when the input RF drive is set at or just below the level which causes peak power output Do not set input drive above 0 dBm Input drive above 20 dBm may damage the unit The reverse power level should remain below 10 of the forward power assuming that the load is properly matched An alterna
6. EF JOHNSON 105 0854 001 TEST JACK BLUE VERTICAL EF JOHNSON 105 0860 001 D SUB 37 PIN FEMALE PCB MOUNT RIGHT ANGLE AMP 745784 4 CONN D SUB 15 PIN MALE STRAIGHT PCB MOUNT POSITRONIC MD15M3000 CONN D SUB 25 PIN MALE RIGHT ANGLE PCB MOUNT AMP 747238 4 SPRING LATCH KIT D SUB AMPHENOL 17 529 RELAY DPDT 5VDC 125V 0 5A 30VDC 1A CONTACTS PCB TERMINALS SEALED OMRON G6H 2 DC5 WIDE BAND CHOKE VK200 10 3B FERROXCUBE TRANSISTOR NPN 2N2222A TO 18 RES 220 OHM 1 4W 5 CC A B RCO7GF221J RES 680 OHM 1 4W 5 CC A B RCO7GF681J RES 200K 1 4W 5 CC A B RCO7GF204J RES 8 2M 1 4W 5 CC A B RCO7GF825J RES 100 OHM 1 2W 1 MF 100PPM DALE RN55D RES 200 OHM 1 2W 1 MF 100PPM DALE RN55D RES 243 OHM 1 2W 1 MF 100PPM DALE RN55D RES 845 OHM 1 2W 1 MF 100PPM DALE RN55D RES 33 2K 1 2W 1 MF 100PPM DALE RN55D TRIMPOT 10K 1 2W 10 CERMET 100PPM 20T TOP ADJ BECKMAN 67W RES 10K 1 8W 1 MF AXIAL 100PPM DALE CMF 50 RN50C1002F RES 1K 1 8W 1 MF 50PPM DALE 50 RES 100K 1 20W 1 FILM AXIAL 100PPM MIL DALE RN50C1003F IC ULTRA LOW NOISE PRECISION OP AMP ANALOG DEVICES OP27GP CONVERTER NO OIL 16BIT A TO D SERIAL OUT BURR BROWN ADS7809PB PB ANALOG DEVICES AD977CN IC INSTRUMENTATION AMP ANALOG DEVICES AD524A SSD IC DUAL 16 BIT DIGITAL TO ANALOG CONVERTER BURR BROWN DAC 725 SSD IC ADJUSTABLE VOLTAGE REGULATOR 15W 1 5A TO 220 NAT LM317T IC 4CH ANALOG MULTIPLEXER
7. deep enough so that it ceases to be a problem To preclude this gassing problem and thus reduce the need for repeating the Operate selection it is recommended that the time in Standby be limited to about one hour Extended periods in Standby may result in an inability to clear the fault by this method In this case service measures may be needed to correct the unit Thus users should reduce the likelihood of occurrence of this problem by limiting the amount of time in the Standby mode The service measures involve pulsing of the tube beam current and gradually increasing the duty of the pulsing until the unit will operate continuously Note that a similar condition can exist for tubes with grids when the TWTA is in the Operate mode high voltage is on but gating control input is set so that the grid turns off the TWT beam current Operational procedures should also limit the time in this mode 24 Rev B 4 MAINTENANCE The TWTA does not reguire routine scheduled maintenance The only moving parts are the elements of switches relays and blowers Preventive maintenance is recommended in Paragraph 4 3 The TWTA is basically a factory repairable unit However since limited logic schematics and partial parts information is supplied in this manual Section V some user service organizations may choose to perform their own corrective maintenance Warnings and Cautions should be observed 4 1 SAFETY WARNING
8. 1 FAILURE KEMET 4 CKRO5 SERIES W V OPTION C3 C9 C10 C13 C14 C17 C31032 000 CAP 0 01MF 200VDC 10 CER 1 FAILURE KEMET 16 C19 C21 C22 C27 C28 CKRO6 SERIES W V OPTION C30 C31 C33 C36 C46 C61 C31033 000 CAP 0 022MF 100VDC 10 CER 1 1 FAILURE KEMET CKR06B223K W V OPTION C24 C60 C31036 000 CAP 0 1MF 100VDC 10 CER 1 FAILURE KEMET 2 CKRO6 SERIES W V OPTION C1 C4 C6 C7 C16 C31040 000 CAP 1MF 50VDC 10 CER 1 FAILURE KEMET 20 C18 C25 C26 C32 CKRO6 SERIES W V OPTION C34 C37 C38 C39 C40 C41 C43 C44 C45 C48 C49 D16 D23 D31 D10965 000 ZENER 15V DIODES INC 1N965B 3 D1 D3 D4 D5 D7 D8 D9 D14454 000 DIODE AXIAL MOTOROLA 1N4454 24 D10 011 012 D13 D17 D18 D19 D21 D22 D25 D26 D28 D30 D35 D37 D36 D14733 000 ZENER 5 1V 1W 10 AXIAL MOTOROLA 1N4733 1 F00010 000 WASHER 2 LOCK SST 3 F10086 000 PHP 2 56 X 3 16SST 3 J2 J10370 000 CONN 37 PIN MALE D SUB PCB RIGHT ANGLE 1 AMP 747252 4 J18075 000 MALE SCREW LOCK FOR D SUBMIN CONN AMP 1 205817 1 J4 J5 J18086 000 CONN SMA JACK RECEPTACLE RIGHT 0 2 18GHZ PC MOUNT JOHNSON COMPONENTS 142 0701 301 J1 N25003 000 HYPERTRONICS CONN 29 PIN MALE RIGHT 1 ANGLE CUT ENDS Q2 Q22907 000 TRANSISTOR PNP 2N2907A TO 18 1 R1 R9 R19 R37 R44 R50 00100 000 RES 10 OHM 1 4W 5 CC A B RCO7GF100J 6 R4 R20 R27 R29 R01100 000 RES 100 OHM 1 4W 5 CC A B RCO7GF101J 4 R5 R17 R18 R28 R34 R45 02100 000 RES 1K 1 4W 5 C
9. 6 which allows entering the desired number of alarm beeps and the desired beep volume S1 SET toggles between parameters and the adjust knob is used to enter the data Setup 7 allows the IEEE 488 address to be set Setup 8 allows selecting between pulsed or CW operation The SET button toggles between the two MORE returns you to SETUP 1 EXIT returns you from any of the setup screens to MENU 2 Sleep Mode The Sleep Mode feature allows the user to selectively shut off the heater module of the power supplies This can be done manually through the front panel or remotely via the computer interface This is typically used during extended periods of remote operation to improve tube life by turning off the filaments Sleep Mode activated This eliminates excessive STANDBY hours on the TWTs while still permitting remote capability to turn on the amplifier To activate Sleep Mode locally Press the MORE soft key to get to MENU 2 At MENU 2 press the SETUP soft key to get to SETUP 1 At SETUP 1 press SET to activate Sleep Mode turn heater and fan off The system will ask are you sure Press SET again After activating the Sleep Mode Screen will display Cooling On while heaters cool down System Off notifies user that the amplifier is in Sleep Mode Rev B 13 Model 20T4G18 To deactivate Sleep Mode locally Press the ON soft key to de activate Sleep Mode Amplifier will return to MENU 1 When de activating the Sleep Mode the h
10. DATEL MXD 409 IC 8 COMMON CATHODE CLAMPIMG DIODES 9 PIN SIP ROHM DAN801 8 COMMON ANODE CLAMPING DIODES 9PIN SIP ROHM DAP801 IC 6 5536MHZ CLOCK OSCILLATOR 1 2 SIZE ECLIPTEK EC1100HS 6 5536MHZ SSD IC VERSALINK TRANSMITTER HORIZONTAL 200UM FIBER HEWLETT PACKARD HFBR 1528 OPTIC RECEIVER HORIZONTAL HFBR 2521 SSD DRIVER OIL DS75451N DUAL AND NATIONAL SEMICONDUCTOR DS75451N QUANTITY 1 1 12 11 Rev B REF DESIG U6 019 034 039 U60 042 051 052 032 035 047 041 048 045 043 022 024 957 04 049 058 044 046 05 013 014 023 U25 033 050 02 031 053 03 012 028 037 038 6 RP1 RP5 U56 U55 Rev B ETM P N U20148 000 U20730 000 U21328 000 U21388 000 U21536 000 U22598 000 U23909 000 U24018 000 U24138 000 U26889 000 U28008 000 U28032 000 U28040 000 U28074 000 U28123 000 U28164 000 U28165 000 U32001 000 U32103 000 U40008 000 U40012 000 Model 20T4G18 DESCRIPTION INVERTER SCHMIDTT TRIGGER 74HC14 SSD IC DUAL J K FLIP FLOP W RESET 7473 SSD IC QUAD 2 INPUT NAND SCHMIDTT TRIGGER 74HC132 SSD IC 3 TO 8 DECODER DEMULTIPLEXER INVERTING 74HC138 SSD IC DUAL 4 INPUT DIGTAL MULTIPLEXER 74F153 SSD IC 8 BIT ADDRESSABLE LATCH W RESET 74HC259 SSD IC DUAL 4 BIT BINARY BIQUINARY COUNTER 74HCT390 SSD IC JOHNSON DECADE COUNTER W 10 DECODED OUTPUTS 74HC4017 SS
11. It is designed to be used in the process of generating controlling and measuring high levels of electromagnetic Radio Freguency RF energy Therefore the output of the amplifier must be connected to an appropriate load such as an antenna or field generating device It is the responsibility of the user to assure that the device is operated in a location which will control the radiated energy such that it will not cause injury and will not violate regulatory levels of electromagnetic interference HAZARDOUS RF VOLTAGES The RF voltages on the center pin of the RF output connector can be hazardous The RF output connector should be connected to a load before AC power is applied to the amplifier Do not come into contact with the center pin of the RF output connector or accessories connected to it Place the eguipment in a non operating condition before disconnecting or connecting the load to the RF output connector SAFETY GROUND This eguipment is provided with a protective earth terminal The main power source to the eguipment must supply an uninterrupted safety ground of sufficient size to the input wiring terminals power cord or supplied power cord set The eguipment MUST NOT BE USED if this protection is impaired PHYSICAL DAMAGE The RF amplifier should not be operated if there is physical damage missing hardware or missing panels MAINTENANCE CAUTION Adjustment maintenance or repair of the eguipment must be performed o
12. SLEEVES SAMTEC 320 SGT XU15 J14281 000 SKT DIP 28 SLEEVES SAMTEC 628 SGT TPO J16210 000 TEST JACK BLACK VERTICAL EF JOHNSON 105 0853 001 TP1 J16211 000 TEST JACK BROWN VERTICAL EF JOHNSON 105 0858 001 TP2 J16212 000 TEST JACK RED VERTICAL EF JOHNSON 105 0852 001 TP3 J16213 000 TEST JACK ORANGE VERTICAL EF JOHNSON 105 Rev 0856 001 QUANTITY 1 1 10 61 44 41 Model 20T4G18 REF DESIG TP4 TP5 TP6 J4 J3 J2 XJ1 XJ4 K1 K6 L1 L4 Q1 Q2 Q3 04 Q5 Q6 Q7 Q8 R2 R41 R1 R4 R7 R6 R8 R58 R57 R11 R16 R59 R3 R5 R9 R12 R15 R22 R35 R36 R40 R44 R17 R19 R20 R21 R23 R25 R28 R31 R42 R43 R46 R18 R13 R14 R24 R26 R27 R29 R32 R37 R38 R39 R47 U7 U8 U26 U17 U15 U1 U9 U10 U18 DP2 DP4 DP5 DP8 DP9 DP1 DP3 DP6 DP7 DP10 U27 U40 U54 U36 42 ETM P N J16214 000 J16215 000 J16216 000 J18167 000 J18180 000 J31013 000 J31014 000 K02009 000 L00200 000 Q22222 000 01220 000 01680 000 04200 000 05820 000 20100 000 20200 000 20243 000 20845 000 22332 000 R30071 000 R30103 000 R30140 000 R31164 000 000027 000 000029 000 000524 000 000725 000 003171 000 004090 000 008010 000 008011 000 011165 000 011528 000 012521 000 017545 000 DESCRIPTION TEST JACK YELLOW VERTICAL EF JOHNSON 105 0857 001 TEST JACK GREEN VERTICAL
13. baseplate temperature C or F MENU 4 Heater voltage Ef Heater current If Collector voltage Eb Cathode voltage Ek Helix current Iw Help Screens On each of the menu screens soft key S3 is labeled HELP If S3 is selected a message describing the functions of that screen will be displayed Use the ADJUST knob to scroll through the message The EXIT key will return you to the screen from which the help screen was called Setup Screens From MENU 2 S1 labeled SETUP selects the first of several setup screens SETUP 1 This allows the user to manually shut off the heater power supply and put the HPA into Sleep Mode see below Pressing 51 SET toggles between and OFF Pressing MORE again brings up the SETUP 2 screen which allows the user to change the Auto Sleep Mode timer setting Pressing SET will change the timer options in half hour increments from 0 5 to 3 0 hours Pressing MORE again will save the timer setting and bring up the SETUP 3 screen which toggles the display of temperature parameters between Fahrenheit and Celsius degrees Pressing S1 SET changes the selection The setting displayed when the screen is exited will be retained Pressing MORE again brings up the SETUP 4 screen which allows a choice of displaying forward power in watts dBm or bar graph Pressing MORE a third time brings up SETUP 5 which allows a choice of watts dBm or of forward power for displaying reverse power MORE brings up SETUP
14. parameter is performed as above MORE brings up WARNINGS 5 identical to the previous screen except that it deals with the maximum TWT collector block temperature If either parameter exceeds the setpoint the audible alarm will sound every 30 seconds if configured and a warning message will appear on line 3 of MENU 1 From WARNINGS 5 MORE brings up WARNINGS 6 which permits setting the maximum helix current Any helix current above this setpoint will result in an audible alarm if configured repeated every 30 seconds and a warning message is displayed on the status line of MENU 1 Pressing MORE again returns display to WARNINGS 1 As before pressing EXIT from any of the warnings screens returns display to MENU 3 Info Screen From MENU 2 S2 labeled INFO selects a screen that displays the RF sample port calibration factors at various frequencies across the band In addition this screen displays the model number serial number and firmware revision information which may be required by a service representative when providing technical assistance The EXIT key returns the display to MENU 2 Event Screen From MENU 4 S2 labeled EVENT provides a display of events logged by the control system These events include AC power up heater warm up change from standby to operate faults and resets The events are stored in a first in first out FIFO software buffer that has room for 100 events as new events are logged the older ones are dis
15. 0 TRIMPOT 1K 1 2W 10 CERMET 1T SIDE 1 ADJ BECKMAN 72XL R20 R20267 000 RES 267 OHM 1 2W 1 MF 100PPM DALE RN55D 1 R10 R11 R12 R23100 000 RES 100K 1 2W 1 MF 100PPM DALE RN55D 3 R2 R30074 000 TRIMPOT 1K 1 2W 10 CERMET 100PPM 20T TOP 1 ADJ BECKMAN 67W S2 S3 S22004 000 SWITCH TOGGLE DPDT PC MNT AUGAT MTA 2 206 51 522010 000 SWITCH TOGGLE 4PDT ON NONE ON 125V 0 1 6A AUGAT MTA 406N PC U2 U11458 000 IC DUAL LM1458CN 1 U1 U17805 000 IC 5V REGULATOR TO 220 NAT LM340T 5 0 1 Rev B 39 Model 20T4G18 5 4 4 Parts List Emergency Bypass Board A24830 002 REF DESIG ETM P N DESCRIPTION GUANTITY B24830 000 EMERGENCY BYPASS BOARD 1 C3 C5 C04105 000 CAP 0 1MF 100V 20 MON KEMET 3 C331C104M1R5CA C6 C30010 000 CAP 10MF 35V TANT RADIAL NEMCO TB10 35K1 1 C1 C2 C31032 000 CAP 0 01MF 200VDC 1096 CER 196 FAILURE KEMET 2 CKRO06 SERIES W V OPTION C7 C31040 000 CAP 1MF 50VDC 10 CER 1 FAILURE KEMET 1 CKRO06 SERIES W V OPTION D1 D2 D14454 000 DIODE AXIAL MOTOROLA 1N4454 2 D3 D4 D14733 000 ZENER 5 1V 1W 10 AXIAL MOTOROLA 1N4733 2 l4 110096 000 LED GREEN DIFFUSED T1 3 4 XC55G 1 TP2 J16212 000 TEST JACK RED VERTICAL EF JOHNSON 105 0852 1 001 TP3 J16213 000 TEST JACK ORANGE VERTICAL EF JOHNSON 105 1 0856 001 J2 J18086 000 CONN SMA JACK RECEPTACLE RIGHT 0 1 18GHZ PC MOUNT JOHNSON COMPONENTS 142 0701 301 J1 J31055 000 CONN D SUB 15 PIN FEMALE STRAIGH
16. 01 39 5 4 4 Parts List Emergency Bypass Board A24830 002 40 5 4 5 Parts List HPA Interface Board Plastic A25444 000 41 Model 20T4G18 5 4 6 Parts List HPA 20W 4 2 18GHZ AR 28825 300 44 5 4 7 Parts List Microwave Power Assembly AR 28826 000 45 5 5 Recommended Spare Parts rece iia 46 5 6 Sample Program for IEEE 488 Communication essere 47 ILLUSTRATIONS Figure 3 1 Rear View Of HPA ii 9 Figure 3 2 Front Panel Features i 11 Figure 3 3 Front Panel Display Screens i 12 Figure 3 4 TWTA Rear Panel Features eene nnns 15 TABLES Table 1 Front Panel Features 9 Table 2 Rear Panel Features iii 15 Table 3 Catalog of IEEE 488 CommandSs aaa 17 Table 4 Catalog of Status Codes nuansa 18 Table 5 Catalog of Fault Codes n anan 19 Table 6 Catalog of System State Codes 19 Table 7 Catalog of STA Response Codes sassa 20 Table 8 Catalog of STB Response C
17. 28826 000 QUANTITY 1 1 45 Model 20T4G18 5 5 RECOMMENDED SPARE PARTS A16491 000 Auxiliary power supply module low voltage power supply A21455 100 High voltage diode cap assembly A21454 000 High voltage filter assembly A10010 000 Heater power supply module Y10057 000 Spinnaker DC blower Comair Rotron model SPD24B1 part no 032183 46 Rev B Model 20T4G18 5 6 SAMPLE PROGRAM FOR IEEE 488 COMMUNICATION 1000 l K k k K lt lt x lt lt lt k k k lt lt k k k k x lt k lt lt lt k k lt lt k k lt lt k X k k k k k k X X x 1010 x EEE 488 COMMUNICATIONS SOFTWARE 1030 7 24 92 AARON D MCCLURE 1040 psi de di dio dir di di div di dio div dir di div div dio di dir dir dio dio di di dio di di di dir div dio di di dir dio di dir dir dio div dio di dio di di di did 1041 DIM FS 80 1042 DIM AS 80 1050 CLEAR SCREEN 1060 INPUT INPUT COMMAND TO SEND TO POWER SUPPLY EXIT TO QUIT AS 1070 IF AS EXIT THEN 1130 1080 OUTPUT 701 A 1090 IF A 1 2 lt gt RD THEN GOTO 1060 1095 IF AS 1 1 THEN GOTO 1100 1100 ENTER 701 F 110 PRINT OUTPUT FROM COMMAND A IS F 1120 GOTO 1060 130 CLEAR SCREEN 1140 END Rev B 47 Model 20T4G18 48 Rev B WARRAN
18. Assembly A21454 Low voltage interconnects between the power supply modules are through a motherboard It is installed in a finned heat sink assembly to which the modules are bolted The heat sink is cooled by the incoming cabinet air The Heat Sink Motherboard assembly is A23711 000 6 Rev B 3 OPERATION 3 1 WARNINGS AND CAUTIONS Throughout this manual the symbol Rev B A AN WARNING indicates that a hazard exists that may result in personal injury or loss of life CAUTION indicates that failure to follow procedures may result in damage to the equipment WARNING DANGER High Voltage Present Electrical equipment in this TWTA generates and stores high voltage energy that can result in fatal electrocution Do not operate the TWTA with covers or the front panel removed Service work must be performed only by technicians thoroughly familiar with the high voltages present in microwave tube amplifiers in general and with this equipment in particular Never handle the TWT leads or the high voltage connectors unless the unit has been unplugged and it has been positively established that the high voltage filter capacitors have been discharged to a known safe level WARNING Safety Ground Improper grounding of this equipment can result in electric shock The TWTA must be operated only with a line cord with a safety ground wire It is the user s responsibility to ascertain that the power connector is prope
19. C A B RCO7GF102J 12 R49 R53 R54 R59 R71 R88 R6 02270 000 RES 2 7K 1 4W 5 CC A B RCO7GF272J 1 R30 R31 R36 02470 000 RES 4 7K 1 4W 5 CC A B RCO7GF472J 3 R86 R87 02510 000 RES 5 1K 1 4W 5 CC A B RCO7GF512J 2 R75 02560 000 RES 5 6K 1 4W 5 CC A B RCO7GF562J 1 R38 R77 R90 03100 000 RES 10K 1 4W 5 CC A B RCO7GF103J 3 R32 R03470 000 RES 47K 1 4W 5 CC A B RCO7GF473J 1 R35 05820 000 RES 8 2M 1 4W 596 CC A B RCO7GF825J 1 R13 R14 R10002 000 TRIMPOT 5K 1 2W 10 CERMET 20T SIDE 2 ADJ BOURNS 3296X 1 502 R76 R21499 000 RES 4 99K 1 2W 1 MF 100PPM DALE RN55D 1 R10 R21523 000 RES 5 23K 1 2W 1 MF 100PPM DALE RN55D 1 R16 R21866 000 RES 8 66K 1 2W 1 MF 100PPM DALE RN55D 1 R52 R73 R21887 000 RES 8 87K 1 2W 1 MF 100PPM DALE RN55D 2 36 Rev B Model 20T4G18 REF DESIG ETM P N DESCRIPTION GUANTITY R67 R21953 000 RES 9 53K 1 2W 1 MF 100PPM DALE RN55D 1 R47 R48 R22200 000 RES 20K 1 2W 1 MF 100PPM DALE RN55D 2 R79 R80 R22470 000 RES 47K 1 2W 1 MF 100PPM DALE RN55D 2 R42 R60 R61 R89 R23100 000 RES 100K 1 2W 1 MF 100PPM DALE RN55D 4 R33 R55 R23698 000 RES 698K 1 2W 1 MF 100PPM DALE RN55D 2 R41 R23750 000 RES 750K 1 2W 1 MF 100PPM DALE RN55D 1 R21 R23845 000 RES 845K 1 2W 1 MF 100PPM DALE RN55D 1 R66 R23953 000 RES 953K 1 2W 1 MF 100PPM DALE RN55D 1 R12 R15 R32020 000 TRIMPOT 1 2W 10 CERMET 20T SIDE 2 ADJ BECKMAN 67X U4 U5 U6 U02390 000 IC QUAD COMPARATO
20. D 8 BIT BINARY DOWN COUNTER 74HC40103 SSD IC 8 BIT MAGNITUDE COMPARATOR 74HCT688 SSD IC OUAD 2 INPUT AND 74HC08 SSD IC QUAD 2 INPUT OR 74HC32 SSD 12 BIT DECADE COUNTER 74HCT4040 SSD IC DUAL D FLIP FLOP W RESET 74HC74 SSD IC DUAL RETRIGGERABLE 1 SHOT 74HC123 SSD IC 8 BIT SERIAL IN PARALLEL OUT SHIFT REGISTER 74HC164 SSD 8 BIT PARALLEL IN SERIAL OUT SHIFT REGISTER 74HC165 SSD IC 1K FEED THROUGH RES NETWORK 16 PIN DIP A B 316B102 IC 10K FEED THROUGH RES NETWORK 16 DIP A B 316B103 REGULATOR OIL 5V 100MA TO 92 MOTOROLA MC78LO5ABP FLIP FLOP OCTAL D TYPE LATCH WITH RESET NATIONAL MM74HC273N QUANTITY 5 1 1 43 Model 20T4G18 5 4 6 Parts List HPA 20W 4 2 18GHZ AR A28825 300 REF DESIG ETM P N DESCRIPTION GUANTITY A1 A23720 099 POWER SUPPLY SHORT FOR TWT 5172 1 A5 A24830 001 EMERGENCY BYPASS BOARD 1 A11 A24830 002 EMERGENCY BYPASS BOARD 1 A3 A25403 302 TWTA CONTROL ASSY 20 CIJ 50X 1 4 25444 000 HPA INTERFACE BOARD PLASTIC FIBERS 1 A12 A25498 000 WIRING 20W 1 A2 A28826 000 MICROWAVE POWER ASSEMBLY AR 20CIJ 1 AQ A28827 000 CABINET ASSY AR 20CIJ CPI TWT 1 44 Rev B 5 4 7 REF DESIG W3 W6 W5 w2 A1 A2 R1 R2 4 5 D1 D2 W4 A3 J1 J2 Rev B ETM P N 00888 007 00888 009 00888 012 00888 015 00888 020 01122 000 08137 000 20012 000 20064 000
21. ECIAL HEATER POWER SUPPLY MODULE XFMR HEATER FEEDBACK XFMR HEATER POWER FACTORY SELECT PARTS MICROWAVE POWER ASSEMBLY AR 20CIJ TWTA CONTROL ASSY 20 CIJ 50X CPU BOARD W POWERFAIL 20MHZ HPA DISPLAY BOARD GPIB INTERFACE BOARD 3U TWT PRODUCTS HPA INTERFACE BOARD PLASTIC FIBERS EMERGENCY BYPASS BOARD CABINET ASSY AR 20CIJ CPI TWT EMERGENCY BYPASS BOARD WIRING 20W C I J Rev B 5 2 SCHEMATICS 10 16485 000 10 25444 000 10 24830 10 24830 002 10 28825 300 Rev B HPA Logic and Control 16485 000 HPA Interface A22444 000 Emergency Bypass Board A24830 001 Emergency Bypass Board A24830 002 HPA 20T Series A28825 300 Model 20T4G18 31 Model 20T4G18 32 Rev B Model 20T4G18 5 3 WIRING DIAGRAMS 20 23720 099 TWT Power Supply AR 20T Series A23720 099 Rev B 33 Model 20T4G18 34 Rev B 5 4 PARTSLISTS A16485 000 A23720 099 A24830 001 A24830 002 A25444 000 A28825 300 A28826 000 Rev B HPA Logic and Control Assembly Power Supply Short for TWT 5172 Emergency bypass board Emergency bypass board HPA Interface Board Plastic HPA 20W 4 2 18GHZ AR Microwave Power Assembly Model 20T4G18 35 Model 20T4G18 5 4 1 Parts List HPA Logic and Control Module A16485 000 REF DESIG ETM P N DESCRIPTION GUANTITY B16485 000 HPA LOGIC AND CONTROL BOARD 1 11 16333 000 CAP 33MF 25V AERL NICHICON UVX1E330M 1 C2 C5 C15 C58 C31028 000 CAP 1000PF 200VDC 10 CER
22. ICON UVR1C221MEA C47 C67 C17224 000 CAP 220MF 50V AERL ILL 227RAR050A C44 C168 C169 C30066 000 CAP 47 MF 35V SOLID TANT RADIAL KEMET T356M476K035AS C165 C166 C6 C7 C9 C13 C31016 000 CAP 100PF 200VDC 10 CER 1 FAILURE KEMET C16 C39 CKRO5 SERIES W V OPTION 107 108 109 110 111 112 C31036 000 CAP 0 1MF 100VDC 10 CER 1 FAILURE KEMET 113 114 115 116 117 121 CKRO6 SERIES W V OPTION 125 132 167 1 2 3 4 5 10 11 22 23 24 25 26 28 30 33 35 40 41 42 48 49 50 51 53 62 63 64 65 70 71 73 77 79 83 85 87 88 89 91 94 96 97 98 102 C12 C14 C21 C27 C29 C31040 000 CAP 1MF 50VDC 10 CER 1 FAILURE KEMET C31 C34 C36 C38 C17 CKRO6 SERIES W V OPTION C18 C19 C37 C54 C55 C56 C57 C58 C59 C60 C61 C118 C119 C120 C122 C123 C124 C133 C46 C52 C66 C68 C72 C75 C82 C84 C86 C90 C92 C93 C95 C104 C106 D8 D10 D16 D18 D19 D14007 000 DIODE 1000V 1A AXIAL MOTOROLA 1N4007 D1 D7 D14454 000 DIODE AXIAL MOTOROLA 1N4454 D9 D17 D14733 000 ZENER 5 1V 1W 10 AXIAL MOTOROLA 1N4733 11 110074 000 LED GREEN ALGAAS NON DIFFUSED HEWLETT PACKARD HLMP 1540 J5 J10021 000 HEADER 2 PIN MALE RIGHT ANGLE SERIES 7478 MOLEX 22 05 3021 J1 J10371 000 D SUB 37 PIN MALE PCB MOUNT STRAIGHT POSITRONICS MD37M3S000 XU17 J14161 000 SKT DIP 16 SLEEVES AUGAT 516 AG11D XU26 J14202 000 SKT DIP 20
23. Iwz RDTMPTWTF Returns TWT temp F F TWTF F RDTMPTWTC Returns TWT temp C C TWTC C RDTMPPSF Returns power supply temp F F PSF F RDTMPPSC Returns power supply temp C C PSC C RDTWTOTF Returns TWT overtemp warning setpoint F F TWTOTF JF STWTOTF Sets TWT overtemp warning setpoint F F RDTWTOTC Returns TWT overtemp warning setpoint C C TWTOTC C STWTOTC Sets TWT overtemp warning setpoint C C RDPSOTF Returns power supply overtemp warning setpoint F F PSOTF JF SPSOTF Sets p s overtemp warning setpoint F F RDPSOTC Returns p s overtemp warning setpoint C PSOTC C SPSOTC Sets p s overtemp warning setpoint C C RDIWOC Returns helix overcurrent warning setpoint mA IWOC SIWOC Sets helix overcurrent warning setpoint mA RDLOGIC Returns logic state code see Table 6 Sys RDA Returns gain A SA Sets gain 18 Rev B Command RDHTDREM RDPOD RDPOW RDPRD RDPRW RDPOHID SPOHID RDPOLOD SPOLOD RDPOHIW SPOHIW RDPOLOW SPOLOW RDPRHID SPPRHID RDPRHIW SPRHIW SYSTEM ON SYSTEM OFF RDHTRAUTOOFF SHTRAUTOOFF IDN STA STB Function Returns remaining heater time delay Returns forward power out dBm Returns forward power out W Returns reverse power out dBm Returns reverse power out W Returns over forward power warning setpoint dBm Sets over forward power warning setpoint dBm Returns under forward power warning setpoi
24. R NAT LM139J 3 U7 U03240 000 IC LOW POWER OP AMP NAT LM324 1 U9 U10070 000 REFERENCE PRECISION 10V LINEAR TECH 1 LT1031DCH U8 U17805 000 REGULATOR TO 220 NAT LM340T 5 0 1 UT U2 U3 U20148 000 IC HEX INVERTER SCHMIDTT TRIGGER 74HC14 3 SSD RP8 U30106 000 IC 10K RES NETWORK 6 PIN SIP DALE MSPOGA 01 1 103G RP1 2 RP5 7 RP9 U30410 000 1C 10K 296 0 40A 10 PIN ISOLATED RESISTORS 6 DALE MSP10C 03 103G OR BOURNS 4610H 102 103 RP4 U31020 000 IC 1K RES NETWORK SIP BECKMAN L061C102G 1 W3 W8 W12200 000 WIRE 22 AWG BLU 600V TEFLON BELDEN 6 83006 Rev B 37 Model 20T4G18 5 4 2 Parts List Power Supply Short For TWT 5172 A23720 099 REF DESIG ETM P N DESCRIPTION GUANTITY 2 1001000 HEATERPOWERSUPPLYMODULE TT mw 41007 00 PWMBOARD SPECAL 07 A3 A16485 000 HPALOGICANDCONTROLMODUE gt 622 A2485 00 HIGHVOLTAGEDIODE CAPASSYFOR 100WKU gt T CA7 A21457 001 AV FILTERMODULE 1 42368340777 POWER FACTOR MODULE 800W 4 CAM 49367 00 LOW VOLTAGE POWER SUPPLYMODUE gt o 7T 5 49371000 POWERASSEMBLYFORT WKU NT AT A23711 000 MOTHERBOARD AND HEATSINK 1 ao 42451309 FACTORYSELECT PARIS 4 38 Rev B Model 20T4G18 5 4 3 Parts List Emergency Bypass Board A24830 001 REF DESIG ETM P N DESCRIPTION GUANTITY B24830 000 EMERGENCY BYPASS BOARD 1 C3 C5 04105 000 CAP 0 1MF 100V 20 MON KEMET 3 C331C104M1R5CA C6 C30010 000 CAP 10MF 35V
25. S RF Susceptibility testing Antenna and component testing Equipment calibration General laboratory instrumentation 1 3 SPECIFICATIONS Refer to the Amplifier Research Data Sheet on the following pages for detailed specifications 1 4 ACCESSORIES Amplifier Research offers a number of accessories for use with this amplifier including e Directional coupler e Antenna e Flexible transmission line Refer to a current Amplifier Research catalogue for Microwave Accessories Rev 1 Model 20T4G18 1 5 TEST DATA SHEET A Test Data Sheet for a specific unit is prepared at the time of manufacture and is included with the unit s copy of this manual Rev B af AMPLIFIER RESEARCH MODEL 20T4G18 160 School House Road Souderton PA 18964 9990 USA 1 M2 Phone 215 723 8181 FAX 215 723 5688 20 WATTS CW 4 2 18 GHz The Model 20T4G18 is a self contained forced air cooled broadband traveling wave tube TWT microwave amplifier designed for applications where wide instantaneous bandwidth high gain and moderate power output are required A reliable micro TWT provides a conservative 20 watts minimum at the amplifier output connector Stated power specifications are at fundamental frequency The amplifier s front panel digital display shows forward and reflected output plus extensive system status information accessed through a series of menus via soft keys Status indicators include power on warm up standby operate faul
26. T PCB 1 MOUNT AMPHENOL 17D A15S U Q4 Q5 Q22907 000 TRANSISTOR PNP 2N2907A TO 18 2 R18 R23 R01100 000 RES 100 OHM 1 4W 5 CC A B 076 101 2 R21 R01514 000 RES 510 OHM 1W 5 CC A B RC20GF511J 1 R19 02100 000 RES 1K 1 4W 5 CC A B RCO7GF102J 1 R22 02330 000 RES 3 3K 1 4W 5 CC A B RCO7GF332J 1 R16 R17 02470 000 RES 4 7K 1 4W 5 CC A B RCO7GF472J 2 R9 R13 R15 R03100 000 RES 10K 1 4W 5 CC A B RCO7GF103J 3 R20 R20267 000 RES 267 OHM 1 2W 1 MF 100PPM DALE RN55D 1 R10 R11 R12 R23100 000 RES 100K 1 2W 1 MF 100PPM DALE RN55D 3 R2 R30074 000 TRIMPOT 1K 1 2W 10 CERMET 100PPM 20T TOP 1 ADJ BECKMAN 67W U2 U11458 000 IC DUAL OP AMP NAT LM1458CN 1 U1 U17808 000 IC 8V REGULATOR TO 220 NAT LM340T 8 0 OR 1 LM7808 40 Rev B Model 20T4G18 5 4 5 Parts List HPA Interface Board Plastic A25444 000 REF DESIG ETM P N DESCRIPTION B25444 000 HPA INTERFACE BOARD C161 C03105 000 CAP 0 01MF 100V CER 10 RADIAL AVX SR201C103KAA C171 C04223 000 CAP 0 22MF 35V TANT RADIAL JAMCO 33507 C20 C32 C100 C05153 000 CAP 1 5MF 35V TANT RADIAL AVAX 155 0355 5 129 163 C05223 000 CAP 2 2MF 35V 10 SOLID SEALED TANT RADIAL SPRAGUE 199D225X9035BA1 C80 C81 C164 C06103 000 CAP 10MF 25V 20 SOLID TANT RADIAL AVX TAP106M025HSB C15 C06220 000 CAP 22MF 16V SOLID TANT RADIAL AVX 226 0165 5 C99 C16103 000 CAP 10MF 35V AERL NICHICON UVR1V100MDA C101 C17222 000 CAP 220MF 16V AERL NICH
27. TANT RADIAL NEMCO TB10 35K1 1 C2 C31028 000 CAP 1000PF 200VDC 1096 CER 196 FAILURE KEMET 1 CKRO5 SERIES W V OPTION C1 C31032 000 CAP 0 01MF 200VDC 1096 CER 196 FAILURE KEMET 1 CKRO06 SERIES W V OPTION C7 C31040 000 CAP 1MF 50VDC 1096 CER 196 FAILURE KEMET 1 CKRO06 SERIES W V OPTION D1 D2 D14454 000 DIODE AXIAL MOTOROLA 1N4454 2 D3 D4 D14733 000 ZENER 5 1V 1W 10 AXIAL MOTOROLA 1N4733 2 12 13 110066 000 LED RED HIGH EFFICIENCY HIGH BRIGHTNESS 2 11 14 110096 000 LED GREEN DIFFUSED T1 3 4 XC55G 2 TP2 J16212 000 TEST JACK RED VERTICAL EF JOHNSON 105 0852 1 001 TP3 J16213 000 TEST JACK ORANGE VERTICAL EF JOHNSON 105 1 0856 001 J2 J18086 000 CONN SMA JACK RECEPTACLE RIGHT 0 1 18GHZ PC MOUNT JOHNSON COMPONENTS 142 0701 301 J1 J18180 000 CONN D SUB 15 PIN MALE STRAIGHT PCB MOUNT 1 POSITRONIC MD15M3000 01 03 Q22222 000 TRANSISTOR NPN 2N2222A TO 18 3 Q4 Q5 Q22907 000 TRANSISTOR PNP 2N2907A TO 18 2 R18 R23 R01100 000 RES 100 OHM 1 4W 5 CC A B RCO7GF101J 2 R21 R01150 000 RES 150 OHM 1 4W 5 CC A B RCO7GF151J 1 R19 02100 000 RES 1K 1 4W 5 CC A B RCO7GF102J 1 R3 R5 R7 02220 000 RES 2 2K 1 4W 5 CC A B RCO7GF222J 3 R22 02330 000 RES 3 3K 1 4W 5 CC A B RCO7GF332J 1 R16 R17 02470 000 RES 4 7K 1 4W 5 CC A B RCO7GF472J 2 R24 02510 000 RES 5 1K 1 4W 596 CC A B RCO7GF512J 1 R4 R6 R8 R9 R13 R15 R03100 000 RES 10K 1 4W 5 CC A B RCO7GF103J 6 R1 R12107 00
28. TIES LIMITATION OF LIABILITY Seller warrants 1 that seller has title to the goods sold and 11 that Amplifiers Antennas Pre compliance Test Systems Transient Generators Power Meters Directional Couplers and Tripods will be free from defects in material and workmanship for a period of three 3 years from date of shipment shown on Amplifier Research invoice Field Monitoring Equipment Teseo Fiberoptic Systems and Traveling Wave Tubes in the 200T1G3A 200T2G8A and 200T8G18A will be free from defects in material and workmanship for a period of two 2 years from date of shipment Vacuum tubes traveling wave tubes in models not previously listed and power heads will be free from defects in material and workmanship for a period of one 1 year Contact Amplifier Research for warranty information regarding items not listed Seller s sole responsibility in fulfilling these warranties shall be to repair or replace any goods which do not conform to the foregoing warranties or at seller s option to give buyer credit for defective goods The warranty is valid only when used in the country specified at time of order Warranty service must be obtained from the repair facility designated at that time If warranty service is not available in the country where the equipment is to be used it must be returned to Amplifier Research Warranty service will be provided only for defective goods which are returned within the warranty period freight costs prepai
29. always 1 power on 2 Standby status 0 if not in standby 1 if in standby 3 Operate status 0 if not in operate 1 if in operate 4 Fault status 0 if no fault 1 if fault exists Table 9 Catalog of Heater Auto Off Time Delay Codes Argument Meaning 0 0 5 hour heater auto off time delay 1 1 0 hour heater auto off time delay 2 1 5 hour heater auto off time delay 3 2 0 hour heater auto off time delay 4 2 5 hour heater auto off time delay 5 3 0 hour heater auto off time delay Command syntax is in this form lt command mnemonic gt lt parameter gt lt carriage return gt where lt command mnemonic gt consists of one of any valid command found in Table 3 lt parameter gt as applicable consists of one ASCII space character followed by a number lt carriage return gt consists of an ASCII carriage return All commands are case sensitive The system will return parameter values fault codes and status codes regardless of whether remote is enabled The parameter value is returned as a string of 20 characters or less consisting of a label and a value For example outputting the command RDEF to the TWTA would result in the TWTA sending back the string Ef 6 03 assuming the heater voltage is 6 03 volts Units are usually not returned see table 3 for the units If remote is not enabled set commands and commands to the system logic i e OPERATE or STANDBY or RESET will not be accepted It is recom
30. anyone other than the manufacturer without its written consent and that no right is granted to disclose or so use any information in this document Model 20T4G18 TABLE OF CONTENTS TABLE OF CONTENTS anali i 1 DESCRIPTION AND SPECIFICATION S 1 1 1 eli 1 1 2 Suggested Applications cuta ee th od cease ae eh 1 1 35 Specifications a na 1 124 ACCESOS alia laine 1 1 52 Test Data Sheet e la 2 2 THEORY OF OPERATION 5 2 1 Design of the amplifter eene nennen enne 5 2 2 Description of the RF CIircUit shah unay lt 5 2 3 Description of the Power Supply 4 6 3 OPERATION acia 7 3 Wammngs and Gautfons u L ete erre 7 3 27 Tostadas 8 3 2 1 Unpaid 8 32 27 2Mountifig tee irt eei EM cdots eode 8 3 23 Cooling Requirements rrr ero gr 9 3 2 4 AC Line Power Connections 10 3 252 RE Output Connections de e ne ee Pee detis haya iii 10 3 2 6 External Interlock Connector erne renser snes 10 3 3 Front Panel Features ect ener ta eee deer
31. carded System Shutdown Screen In the event of a system shutdown due to a latched fault 1 e a fault such as body overcurrent or power low line that requires a reset the MENU screen is replaced by a screen indicating the nature of the fault Softkey S4 labeled OK is implemented as a reset key pressing S4 brings back the MENU screens Line 3 of MENU 1 which normally displays the operational state of the TWTA is used as a fault display line until the fault is cleared When the fault clears the system will automatically resume the standby state and high voltage on will be enabled once again 14 Rev B Model 20T4G18 Factory Service Screens A number of screens intended for factory service and calibration are behind passwords and are not accessible to the user System Malfunction Screens A number of screens are reserved to display error messages These messages are not normally seen and indicate a malfunction of the TWTA System malfunction messages include the following Database corrupt Communication failure Cannot restore CU line voltage too low to operate System shutdown In the event that one of these appears shut off the TWTA and contact an authorized service representative before proceeding CAUTION Attempts to operate the TWTA despite control unit problems may result in loss of the static RAM database and calibration information Rev B 15 Model 20T4G18 3 5 REAR PANEL FEATURES See Figure 3 4 below
32. ctronic equipment are best stored in a benign environment at reasonably constant temperature Service life is not improved by periodic operation Availability For critical missions and after long periods of storage it is recommended that TWTA operation be checked sufficiently in advance of the mission to permit repair if required Though service life is not improved by periodic operation users experiencing amplifier trip due to body over current may benefit by periodically operating a unit with high voltage and grid on but no RF drive Such operation for about one hour on a weekly basis should effectively reduce nuisance tripping Since the cathode structure has finite life extended periods of non functional operation of TWTAs is not recommended An alternate approach if periodic trip off has been observed is to operate the unit without RF input for 1 2 hours before planned functional operation resetting the unit after occasional trip off Cooling during Operate Mode AR TWTAs have their air outlets and inlets on the rear panels It is important to prevent the heated air which is expelled from the TWTA s air outlets from being recycled into the air inlets Applications should have a clearance behind the TWTA of at least two feet for single bench top units and at least three feet for the higher power units or the heated air should be ducted away Operation in Standby Mode Standby mode for TWTAs readies the unit for operation In this mode th
33. d to Amplifier Research or its designated repair facility There are no other warranties express or implied including any warranty of merchantability or fitness Seller shall not be responsible for any incidental or consequential damages arising from any breach of warranty No person other than an officer of Amplifier Research Corporation has any authority to bind seller to any affirmation representation or warranty except as specifically included in the preceding terms and conditions 0701
34. downs Model 20T4G18 ADDITIONAL WARNINGS 8 NOTES WARNING This eguipment operates at potentially lethal voltages Only trained gualified personnel should operate maintain or service it Hazardous energy may be present while protective covers are removed from the eguipment even if disconnected from the power source Contact may result in personal injury CAUTION Adjustment maintenance or repair of the eguipment must be performed only by gualified personnel CAUTION A Replacement fuses are required to be of specific type and current rating CAUTION The information in this document was obtained from reliable sources and was believed to be accurate at the time of publication Since subsequent modifications to the machine may have been made use this information only as a guide Carefully compare the unit s actual configuration and operation to the descriptions in this manual before you undertake to operate service or modify this machine Any variance or modification should be noted dated and initialed in the discrepant part of all manuals on hand for future reference If you have technical or editorial comments you wish to make to the manufacturer please write them on photocopies of the relevant sheets NOTE The contents of this document are the property of the manufacturer and this document is delivered on the express condition that it not be disclosed reproduced in whole or in part or used for manufacture for
35. e filaments are on but the high voltage is off TWTAs should not be left in this Standby mode for extended periods Where practical operational procedures should limit the time on Standby mode to less than approximately one hour See Explanation of below Operate Turn on When selecting the Operate mode when high voltage is first turned on there may be some internal TWT arcing which can cause protective circuits to deselect the Operate mode thereby returning the unit to the Standby mode There may be a report of body over current fault In either case if there is no other contraindication the Operate mode may be selected again This procedure maybe repeated if needed up to 25 times until the Operate mode is actually set If this condition persists contact Amplifier Research Service for additional assistance See Explanation of below Noise Power Density NPD TWTAs produce rf noise over their operating frequency range as specified by the Noise Power Density NPD This noise is significantly higher than the noise produced by typical solid Rev B 23 Model 20T4G18 state amplifiers and is inherent in present TWTAs The noise may surprise users new to TWTAs when it accumulates and results in a significant indication in a broadband measurement device such as a power meter or field probe The error produced by this indication is not significant when operating near rated TWTA power levels but may cause difficulty when trying to o
36. eaters will reguire approximately a 5 minute heater time delay Wait the full 5 minutes prior to selecting OPERATE For remote activation of Sleep Mode or to set the Auto Sleep Mode timer remotely see Table 3 in Section 3 8 Warnings Screens From MENU 3 SI labeled WARNINGS selects WARNINGS 1 which allows the operator to enter the maximum forward power The existing value is between brackets pressing SET puts arrows gt lt around the value indicating that the adjust knob is active The effect of the warning setpoint is as follows if the forward power exceeds the setpoint the audible alarm will sound if configured in SETUP 3 This warning will be repeated every thirty seconds until the over forward power condition is cleared In addition a warning message will appear on line 3 the status line of MENU 1 In the event that the alarm is heard the operator should go to MENU 1 to determine the cause Pressing more brings up WARNINGS 2 which allows the under forward power setpoint to be entered Adjusting this to the minimum value causes OFF to be selected disabling this alarm In WARNINGS 3 the maximum reverse power level is set Note that these are warning levels at which the beep sounds the actual maximum reverse power level that generates a system fault is set in hardware in the TWT power supply HPA Logic and Control module 416485 MORE brings up WARNINGS 4 which allows input of the maximum cabinet temperature Entering this
37. f a load If an external isolator is installed at the output of the TWTA either the isolator should have a load capable of dissipating the full output of the TWTA or the isolator load should be provided with a temperature sensing switch The temperature switch should be normally closed self resetting and with a temperature rating such that there is no possibility of damaging the load by overheating before the switch opens The TWTA may be interlocked with the switch by connecting it between pins 3 and 4 of the external interlock connector J2 If no external isolator is used install a jumper between pins 3 and 4 See section 3 2 6 External Interlock Connector below 3 2 6 External Interlock Connector The TWTA is provided with an external interlock capability via a 15 pin female D sub connector J2 To enable the high voltage power supply it is necessary to provide continuity between J2 pins 3 and 4 If the amplifier shuts down because the interlock was opened it will be necessary to reset the system to return to standby see System shutdown screen in Section 3 4 There is an internal jumper between J2 pins 1 and 2 a continuity check through these pins can be used to verify the presence of the amplifier in the instrumentation system Users may adopt this interlock feature to disable the RF output for either equipment protection or as a backup for personnel protection CAUTION Do not rely on the external interlock for personnel protection T
38. f the coupler protrudes through the rear panel of the TWTA to function as the RF output connector The reverse port on the directional coupler is connected to a crystal detector whose output is used for VSWR protection by the power supply logic board for VSWR measurement in the leveling loop and for reverse power measurement on the HPA interface board The forward port output is split by a 10 dB coupler The direct output is connected to a crystal detector via a pad The output of the crystal detector 1s used on the HPA interface board to measure forward power The side port of the coupler is connected to the RF sample port on the rear panel With an optional reverse power sample port on the rear panel an additional 10 dB coupler is connected to the reverse port of the system s dual directional coupler The output port of the 10 dB coupler is connected to a detector diode whose output is used on the HPA interface board to measure reflected power and for VSWR foldback and protection The coupled port of the 10 dB coupler is connected to the reverse power sample port on the rear panel Rev B 5 Model 20T4G18 Amplifier gain is determined by the solid state preamp SSA which has a voltage controlled attenuator The control head determines the output of a digital to analog converter DAC on the HPA interface board The output of the DAC controls the SSA attenuator The emergency bypass board A24830 mounted behind the front panel is prov
39. g the Operate mode In this state the cathode end of the TWT is heating up but the electron Beam is off In other words there is no cathode current As the cathode heats up gas trapped in the structure of the tube can be released thus corrupting the vacuum of the tube If the tube become too gassy arcing may occur when the high voltage is fully applied in the Operate mode Another possible failure mode is a body over current fault when the beam is turned on and the tube is gassy Occasional arcing is normal fora TWT The support components are designed to handle this protecting both the TWT and its support circuitry However if the tube arcs two or three times in rapid succession or worse yet repeatedly a fault will be sensed that will shut the high voltage off thus removing the unit from Operate status The remedy usually recommended is to repeat the selection of the Operate mode until the unit remains in Operate It as been found that most of the faults that can be cleared by this method will be cleared within 25 attempts to enter the Operate mode Once the tube is operating normally gas will continue to evolve at a slow enough rate that the TWTA will not fault This happens because the gas in the tube will interact with the beam and become ionized As the electrons in the beam hit the gas molecules they ionize the gas at which point it is accelerated into the collector structure and buried
40. he front panel display is to permit the operator to access extensive information about the condition and operation of the TWTA To accomplish this a number of informational screens are programmed It is important for the operator to be able to select the screen with the required information Screen selection is accomplished by pressing an appropriate soft key or by pressing the EXIT key When a soft key is active its function is displayed on the bottom line of the display Figure 3 3 provides a roadmap for navigating between the screens Figure 3 3 Front Panel Display Screens Menu screens The screens at the highest level are called menu screens There are four menu screens At power on the MENU screen is displayed Each of the menu screens has the soft key S4 labeled MORE The MORE key S4 causes the next menu screen to appear From MENU 4 MORE causes MENU to reappear In short MORE permits scrolling through the menu screens The EXIT key returns display to MENU 1 from any other menu screen The menu screens display system status and parameter levels They are configured as follows 12 Rev B Model 20T4G18 MENU 1 Forward power watts dBm or bar graph Reverse power watts dBm or of forward power System status if a latched fault exists MENU 1 is displayed with the system shutdown message MENU 2 Console hours active when AC power is on Operate hours active when HV is on MENU 3 Cabinet temperature C or F TWT
41. he intent A of the external interlock feature is to disable the RF output for equipment protection Use proper operating and safety procedures to insure that power is removed for personnel safety 10 Rev B 3 3 FRONT PAN Refer to Figure 3 2 below Model 20T4G18 EL FEATURES 4 x fon CSEH C STANDBY OPERATE Q 8 ps Y 1 NEN Po gt gt Y A N lt 5 ES 1 6 7 8 9 f 3 2 12 Figure 3 2 Front Panel Features Table 1 Front Panel Features Item Title Function 1 MAIN POWER Switchable 16 A circuit breaker connects primary power to power supplies 2 OPERATE Push button turns on high voltage and SSA when all faults and heater delay are cleared 3 STANDBY Push button shuts off SSA and turns off high voltage 4 ADJUST Rotary knob used as an input device to change values of a variety of parameters 5 EXIT Push button terminates various menu selection routines and returns to the previous menu level 6 9 S1 S4 Soft Key push buttons various menu selection functions 10 Display Displays numerous parameter values and fault messages 11 Keylock Switch Allows operator to inhibit the TWTA to enable front panel control or to enable computer control 12 Emergency switch cover Provides access to emergency bypass switches which permit manual control of the amplifier Rev B 11 Model 20T4G18 3 4 FRONT PANEL DISPLAY AND SOFT KEYS The purpose of t
42. ician level servicing It is intended for use by gualified technical personnel who must troubleshoot and repair the TWTA in the field Such repairs are typically limited to replacement of modules or major components For this reason documentation pertaining to the highest levels of the system and to system control logic is included 29 Model 20T4G18 5 1 TOP LEVEL BUILD TREE BUILD TREE FOR SERIAL NUMBER HPA 20W 4 2 18GHZ AR A28825 300 1A1 1A1A1 1A1A2 1A1A3 1A1A4 1A1A4L4 1A1A5 1A1A5L1 LIA 1A1A5T1 E42 1A1A5T2 E41 1A1A6 1A1A7 1A1A8 1A1A9 1 1 9 1 1 1 9 2 1 1 10 1 2 1A3 1A3A1 1A3A2 1A3A3 1A4 1A5 1A9 1A11 1A12 30 A28825 300 A23720 099 A23711 000 A23687 001 A16485 000 A23683 100 09006 000 23710 000 09007 000 09402 000 09403 000 21455 100 09484 000 21457 001 10017 100 10010 000 09409 000 09408 000 24513 099 28826 000 25403 302 25450 000 25425 001 22488 003 25444 000 24830 001 28827 000 24830 002 25498 000 20W 4 2 18GHZ POWER SUPPLY SHORT FOR TWT 5172 MOTHER BOARD AND HEAT SINK LOW VOLTAGE POWER SUPPLY MODULE HPA LOGIC AND CONTROL MODULE POWER FACTOR MODULE 500W PFC INDUCTOR FOR 100VAC 255VAC POWER ASSEMBLY FOR 100WKU INDUCTOR FOR BUCK REGULATOR XFMR GATE DRIVE HAND WOUND XFMR GATE DRIVE HAND WOUND HIGH VOLTAGE DIODE CAP ASSY FOR 100WKU HV XFMR FOR TWT 5181KU HV FILTER MODULE PWM BOARD SP
43. id command 11 Last command failed Data was unparseable 20 Last set command failed Data was beyond high limit 21 Last set command failed Data was beyond low limit 22 Last set command failed Data was out of range 23 Last set command failed Data was wrong polarity 50 Last command failed Local system does not have remote enabled 51 Remote system is not ready to accept commands 60 Command is not allowed in current system state 901 Assert error invalid table argument 902 Assert error invalid calibration Please call a service representative if you observe this error Table 5 Catalog of Fault Codes Returned by RDFLT Command The RDFLT command causes the TWTA to return a string in the form flt code where code is an ACSII number whose meaning is given below Fault Code Meaning 0 No fault 7 System Fault 8 High Line 9 Low Line 10 Cathode overvoltage 11 Body overcurrent 12 Cathode undervoltage 13 Heater undervoltage Fil not ready 14 Heater overcurrent Fil o current 15 Collector undervoltage 16 Inverter fault 17 Internal interlock open 18 Tube arc 19 TWT hardware overtemperature 20 Cabinet hardware overtemperature 23 Over reverse power 49 TWT software overtemperature 50 Cabinet software overtemperature 20 Rev B Model 20T4G18 Table 6 Catalog of System State Codes The RDLOGIC command causes the TWTA to send a string containing an operational state code consisting of 4 ASCII character
44. ided with a circuit that increases the attenuation so that forward power is limited to a level on the order of 50 watts Forward power is also limited so that reverse power does not exceed approximately 20 watts In emergency bypass operation see section 3 7 the gain control signal is provided locally by means of a potentiometer on the emergency bypass board The foldback circuit remains on line in emergency bypass operation 2 3 DESCRIPTION OF THE POWER SUPPLY The TWT power supply is of modular construction Low voltage power for logic and control of the entire power supply assembly is provided by the low voltage power supply module A23687 001 In addition this module provides DC power for the HPA interface and emergency bypass boards Control logic and TWT protection circuits are contained the HPA logic and Control Assembly A16485 000 The Heater Power Supply Module A10010 000 powers the TWT DC heater The Micro TWT requires no separate grid or anode supply The high voltage power supply consists of the following the Power Factor Correction module A23683 100 converts line voltage to DC for the high voltage switching supply Switching transistors are on the Power Board Assembly A23710 000 and switching is controlled by the Pulse Width Modulation PWM Board A10017 100 The high voltage transformer and rectifiers are contained in the High Voltage Diode Cap Assembly A21457 001 The high voltage DC is filtered in the HV Filter
45. imize any flow restrictions Avoid mounting heat producing equipment in the same rack especially below the TWTA Failure to provide adequate cooling can result in the unit s shutting down from overtemperature conditions The TWTA dissipates approximately 500 watts when in the operate mode Rev B 9 Model 20T4G18 3 2 4 AC Line Power Connections AC line power connection to the TWTA is made at the AC inlet which is a female IEC 320 connector line cord suitable for the type of AC outlet used and consistent with local electrical codes must be obtained to mate with J1 Minimum wire size for the line cord is 18 gauge TWTAs destined for the North American market are provided with a terminated 3 wire cord It plugs into normal 120 VAC single phase outlets The amplifier will operate from any line voltage between 99 and 260 VAC 3 2 5 RF Output Connections The RF output coaxial connector is type TNC female CAUTION Never operate the TWTA without a matched output load rated for at least A 100 watts continuous The TWTA is not provided with an output isolator Full reflected power may irreparably damage the TWT Even with no drive looping oscillation can result in RF output high enough to damage the tube if it is operated without a load The VSWR detection and foldback circuit is provided to protect the tube from progressive failure or mismatch of the output load it should not be relied on for protection from the absence o
46. itch S3 selects between solid state amplifier SSA active RF on in the left hand position and SSA off RF off in the right hand position There is a manual control for the gain adjustment as well This is a flat square single turn pot 1 17 Model 20T4G18 CAUTION Do not adjust 20 turn pot R11 its function is to set the foldback RF output level and it is calibrated at the factory 3 8 IEEE 488 OPERATION The TWTA is provided with a communication interface that conforms electrically to the IEEE 488 standard It permits remote emulation of OPERATE STANDBY and RESET push buttons as well as access to parameter measurements system faults gain adjustment and control unit status The following tables summarize the commands and the return codes Table 3 Catalog of IEEE 488 Commands Command Function Units Response format RDSTAT Returns status code of processing of previous command see Table 4 STATUS RDFLT Returns system fault code see Table 5 fit lt OPERATE Emulates OPERATE push button STANDBY Emulate STANDBY push button POWER OFF Emulate STANDBY push button RESET Emulates RESET softkey RDS N Returns serial number s n RDCONHR Returns console hours ConHr RDRFHR Returns RF hours RfHr RDEK Returns cathode voltage KV Ek RDEB Returns collector voltage KV Eb RDEF Returns heater voltage V Ef RDIF Returns heater current A If2 RDIW Returns helix current mA
47. its tuns 4 2 18 GHz instantaneously INPUT FOR RATED QUTPUT 2 2 u eee eee esten tn ense tassa 1 0 milliwatt maximum GAIN at maximum setting 43 dB minimum GAIN ADJUSTMENT continuous range 35 dB minimum INPUT IMPEDANCE REE aaa 50 ohms VSWR 2 0 1 maximum OUTPUT IMPEDANCE 50 ohms VSWR 2 5 1 typical MISMATCH TOLERANCE rrrrrrrerrerirericeriericee resize rio nioee senese zio nio ninzecenicnene Output power foldback protection at reflected power exceeding 20 watts Will operate without damage or oscillation with any magnitude and phase of source and load impedance May oscillate with unshielded open due to coupling to input Should not be tested with connector off MODULATION CAPABILITY Will faithfully reproduce AM FM or pulse modulation appearing on the input signal AM peak envelope power limited to specified power NOISE POWER DENSITY eese eee iinis Minus 80 dBm Hz maximum Minus 90 dBm Hz typical HARMONIC DISTORTION at 20 watts 4 2 4 5GHz Minus 0dBc maximum Minus IdBc typical 4 5 5GHz Minus 1dBc maximum Minus 2dBc typical 5 7GHz Minus 2 5dBc maximum Minus 4dBc typical 7 10 GHz Minus 54 maximu
48. m Minus 9dBc typical 10 12 GHz Minus 8dBc maximum Minus 12dBc typical Above 12 GHz Minus 20dBc maximum Minus 30dBc typical PRIMARY POWER 99 260 VAC 50 60 Hz single phase 600 VA maximumn CONNECTORS RF input Type N female on rear panel RF output Type TNC female on rear panel RF output sample Type N female on rear panel AAA IEEE 488 f sasa reote Ta ditte DB 15 female on rear panel COOLING Gea Forced air self contained fans air entry and exit in rear MODEL CONFIGURATION MODEL NUMBER DESCRIPTION WEIGHT SIZE H x Wx D 20T4G18 With removable enclosure 32 kg 701 50 3 x 16 5 x 68 6 cm 19 8 x 6 5 x 27 in 20T4G18M1 Enclosure removed for rack mounting slides and front handles installed 25 kg 551b 48 3 x 13 3 x 68 6 cm 19 0x 5 25 x 27 in 20T4G18M2 Shipped without an outer cabinet 23 kg 5010 48 3 x 13 3 x 68 6 cm 19 0 5 25 27 2 THEORY OF OPERATION 2 1 DESIGN OF THE AMPLIFIER The model 20T4G18 TWT amplifier consists of four principal subsystems Two of these subsystems the microwave power assembly A28826 000 and the TWT power supply A23720 099 are discussed in sections 2 2 and 2 3 respectively The other two subsystems are the microprocessor control system and the TWTA packaging These both consist of a number of subasse
49. mblies See the build tree in section 5 1 for further information about how the parts lists are structured The heart of the microprocessor control system is the control head assembly A25403 302 which consists of the CPU board A25450 000 the HPA display board A25425 001 and the data link board A22488 The microprocessor control system supervises the power supply provides metering display processes operator front panel inputs and enables communication with a host computer over the IEEE 488 interface The control head is provided with its own power supply and other than thru the IEEE 488 interface bus is electrically isolated from the amplifier Communication with the amplifier is via fiberoptic links to the HPA interface assembly A25444 000 The TWTA packaging consists of cabinet assembly A28827 000 The cooling system utilizes a DC blower with a dedicated DC power supply 2 2 DESCRIPTION OF THE RF CIRCUIT The TWTA consists of two stages of RF amplification a solid state preamp assembly with adjustable gain E01122 000 and a traveling wave tube amplifier E08137 000 The type N RF input connector is located on the rear panel The RF input is fed to the input connector on the solid state preamp The solid state preamp s output drives the RF input of the TWT The RF output of the TWT is a type TNC coaxial connector The output is directed through a short cable to a 35 35 dB dual directional coupler The output TNC connector o
50. mended that the RDSTAT command be used to provide the host program with a report on how a command was processed 22 Rev B Model 20T4G18 A small sample program that can send commands and receive the strings returned by the TWTA is included in section 5 6 It is written in Hewlett Packard s Rocky Mountain BASIC The program assumes that the IEEE 488 bus is at address 7 and that the address of the TWTA is 01 Remote operation is determined by the application software program in the system controller This application program will aid the user in generating the Command Codes and displaying monitoring the Status Codes Consult the application program users instructions for Remote operation procedure The application program should issue only one string at a time After each functional command is issued the status should be checked to ensure that the command has been properly executed The application program should allow sufficient time for the function to be completed before checking the status The application program should facilitate checking the status just prior to issuing a command since the status could have been changed by a fault condition of the amplifier or by operator activation of the amplifier Periodic checking of the status is also recommended 3 9 TWTA GENERAL CONSIDERATIONS This section is intended to offer some guidelines regarding operation storage and use of Amplifier Research TWTAs Storage TWTAs as with other ele
51. n Problem error HPA interface failure appears Fiberoptic link failure 15 VDC supply failure Heater power supply does not come up Defective low voltage power supply module Defective heater power supply module No high voltage Open external interlock Keylock switch on INHIBIT or REMOTE Defective high voltage power supply Voltages normal but no RF output helix current low No RF input Defective remote control board Defective SSA Gain turned down After review of the symptoms of the failure the user may want to check for a loose connector or component especially after rough handling of the unit Look externally for physical damage and internally for unmated or loose parts 26 Rev B Model 20T4G18 The service technician should become familiar with the internal mechanical construction to permit correct re assembly Limited troubleshooting may be conducted with caution based on the failure symptom and an understanding of the logic schematic diagrams 4 5 NON REPAIRABLE MODULES The High Voltage Diode Cap Assembly A21455 100 the High Voltage Filter Assembly A21454 and the Heater Supply A10010 000 are encapsulated modules and are not repairable Contact an authorized service representative if replacement modules are needed Rev B 27 Model 20T4G18 28 Rev B 5 TECHNICAL DOCUMENTATION NOTE Rev B The purpose of this technical documentation section is to provide a guide to the TWTA for techn
52. nly by gualified personnel Hazardous energy may be present while protective covers are removed from the eguipment even if disconnected from the power source Contact may result in personal injury Replacement fuses are reguired to be of specific type and current rating INSTRUCTIONS FOR SAFE OPERATION SAFETY SYMBOLS A Dangerous voltages are present Use extreme care CAUTION The caution symbol denotes a potential hazard Attention must be given to the statement to prevent damage destruction or harm Indicates protective earth terminal RANGE OF ENVIRONMENTAL CONDITIONS This symbol is marked on the equipment when it is necessary for the user to refer to the manual for important safety information This eguipment is designed to be safe under the following environmental conditions Indoor use Altitude up to 2000M Temperature of 5 C to 40 C Maximum relative humidity 80 for temperatures up to 31 C Decreasing linearly to 50 at 40 C e Main supply voltage fluctuations not to exceed 10 of the nominal voltage or minimum and maximum autoranging values e Pollution degree 2 Normally non conductive with occasional condensation While the equipment will not cause hazardous condition over this environmental range its performance may vary COOLING AIR Care should be exercised not to block the cooling air inlets or outlets Cooling air blockage can result in damage to the RF amplifier or intermittent shut
53. nt dBm Sets under forward power warning setpoint dBm Returns over forward power warning setpoint W Sets over forward power warning setpoint W Returns under forward power warning setpoint W Sets under forward power warning setpoint W Returns over reverse power warning setpoint dB Sets over reverse power warning setpoint dBm Returns over reverse power warning setpoint W Sets over reverse power warning setpoint W Emulates pressing the System ON button from System OFF Exit Sleep Mode Emulates pressing the Power Save button Enter Sleep Mode Returns heater auto off delay Sets heater auto off delay see Table 9 Returns the product model number Returns status string see Table 7 Returns status string see Table 8 Units sec dBm watts dBm watts dBm dBm dBm dBm watts watts watts watts dBm dBm watts watts hours Model 20T4G18 Response format HTD Js Po W Pr dBm Pr JW Pohi dBm Polo dBm Pohi JW Polo W Prhi JdBm Prhi JW Rev B 19 Model 20T4G18 Table 4 Catalog of Status Codes The RDSTAT command causes the TWTA to return a string in the form STATUS code where code is an ASCII number whose meaning is given below Status Code Meaning 0 No command was given 1 Last command was successful 2 Last command is in process 3 Last command failed to complete Time out 10 Last command failed Inval
54. odes rense rener tr ner en nes 20 ii 1 DESCRIPTION AND SPECIFICATIONS This manual provides operating interfacing and selected service information pertinent to Amplifier Research Model 20T4G18 Broadband Microwave Amplifier The Model 20T4G18 is a 20 watt C I J band traveling wave tube amplifier TWTA 1 1 TWTA DESCRIPTION The amplifier uses a broadband micro traveling wavetube TWT to provide 20 watts minimum output over the TWT amplifier s full bandwidth The amplifier is well suited for susceptibility and general laboratory testing where instantaneous bandwidth and high gain are reguired The amplifier is completely self contained and packaged for standard 19 inch rack mounting or bench top use The front panel of the rack mountable amplifier is 5 25 inches high and the overall unit is 25 25 inches deep excluding the rear panel connectors For bench top use the amplifier is supplied in an enclosure with integral carrying handles Primary power is 99 260 volts 50 60 Hz single phase An efficient switching power supply design provides minimum power consumption A fast regulation control loop and a high degree of filtering ensure performance within specifications over a wide range of operating conditions The amplifier is fully enclosed and the upper and lower panels of the rack mountable amplifier are interlocked to reduce the likelihood of accidental contact with high voltage 1 2 SUGGESTED APPLICATION
55. on the next page for the locations of threaded holes which may be used for supplementary support of the rear of the TWTA 8 Rev B Model 20T4G18 RF OUTPUT e Ol 2 RF SAMPLE OUT TYPETNC O RE INPUT 00 O 0 DBM 9 5 O 500 VA O GROUND 9 fn 9 5 EXTERNAL amp izntock 29 675 0 865 USE 8 32 FH SCREWS 3 8 1 2 THREAD IN CABINET TO REAR SUPPORT BRACKETS HERE BOTH SIDES Figure 3 1 Rear View of HPA Rack Mounting Configuration If bottom supports are used for rack mount installation of multiple units the amplifiers should be separated vertically by at least 1 3 4 inches This will allow room for necessary support rails and facilitate installation and removal of the units 3 2 3 Cooling Requirements The TWTA is provided with a cooling fan It is important that air movement around the rear of the unit be unobstructed CAUTION For either bench or rack mounting do not position the TWTA in such a A way that the air intake or outlet are blocked or that the exhaust flow is directed into the intake See Paragraph 3 5 for location of air intake and air outlet If the unit is rack mounted make sure that the intake air is 45 C or below If necessary fabricate a short duct to direct the hot exhaust air out of the rack enclosure Great care must be taken to min
56. ove the amplifier from the cabinet or rack as follows NOTE Due to the weight of the unit the removal of the amplifier from the cabinet or rack is a two person operation Disconnect power RF and any other interface connectors On the rear of the unit remove any screws used to connect brackets to the amplifier On the front of the unit remove the four screws holding the front panel onto the cabinet Carefully slide the amplifier out of the front of the cabinet 2 Remove the 12 screws that secure the lower cover and the 12 screws that secure the upper cover Remove the covers to gain access to the interior of the TWTA Vacuum dust and debris from inside the enclosure Clean dust from the TWTA and its flying leads Remove any dirt from around the three high voltage connectors While the cover is off check for loose wires components or fasteners Reassemble in the reverse order 4 4 TROUBLESHOOTING Symptom Possible cause TWT or power supply overtemperature Air inlet filter dirty Collector heat sink dirty Inadequate clearance behind TWTA High air inlet temperature Defective blower or power supply No response when main power turned on Panel open interlock switch open Control module display does not come up unit does not beep when Shorted or defective control module power supply powered up Control module failure Control module does not boot EPROM s missing Control module datalink failure or Communicatio
57. perate high power TWTAs at low output power levels For example consider a hypothetical typical NPD of 76 dBm Hz from a 4 GHz bandwidth amplifier A broadband detector might see the NPD as 76 dBm Hz 10 log 4 x 10 BW factor 76 96 20 dBm or 0 1 watts This power is insignificant for a user operating at 200 watts 53 dBm but may be very noticeable to a user trying to operate below 1 watt 30 dBm One watt is 0 5 of 23dB below rated power for a 200 watt amplifier A field probe user who obtains a 200 V M field with 200 watts may see a field as high as 53dBm 20dBm 33dB below 200 V M 4 5 V M due to this hypothetical NPD For these applications the use of a lower power amplifier is highly recommended especially when considering safety issues Alternatively additional power loss in the form of an added high power microwave attenuator or preferably an increased space loss for radiated fields may be used to lower the noise received by the broadband measurement device Explanation of Limiting the Time in Standby mode and of Repeated Operate Selection Traveling wave tubes tend to get gassy if they are left in a Standby mode for extended periods of time In this Standby mode the heater filament is on but there is no high voltage applied to the collector or high voltage is applied to the collector but the grid is off This is the normal state after a tube s warm up time just prior to enterin
58. rly wired and that the power outlet is grounded WARNING Explosive Atmosphere To avoid explosion never operate this TWTA in an explosive atmosphere This equipment is not certified for operation in an explosive atmosphere Model 20T4G18 3 2 INSTALLATION 3 2 1 Unpacking Upon receiving the TWTA unpack the unit and inspect it for obvious signs of external damage If damage is observed notify the carrier and contact an authorized service representative Save and store the shipping container in case the unit needs to be returned in the future for calibration or repair 3 2 2 Mounting The TWTA may be operated as a standalone benchtop unit or it may be installed in a 19 rack If rack mounting is desired first remove the amplifier from the cabinet then install the amplifier in the rack CAUTION Due to the weight of the unit the removal of the amplifier from the cabinet or rack is a two person operation Before removal disconnect power RF and any other interface connectors On the rear of the unit remove the six screws used to connect brackets to amplifier On the front of the unit remove the four screws holding the front panel to the cabinet Carefully slide the amplifier out of the front of the cabinet CAUTION Never rack mount the TWTA using the front panel alone The chassis is A likely to be damaged unless its weight is supported Bottom support rails must be provided in a rack mount configuration See Figure 3 1
59. s representing hex digits The response is in the form Sys w x y z eol where the hex values of w x v and z are formed as shown below z bit Meaning 0 LSB High voltage on 1 Transmit on 2 Remote mode 3 MSB Fault y bit Meaning 4 LSB Heater time delay expired 5 Under forward power warning 6 Foldback active 7 MSB Inhibit mode x bit Meaning 8 LSB External inhibit 9 Interlock open 10 not used 11 MSB not used w bit Meaning 12 LSB not used 13 Sleep Mode Active 14 not used 15 MSB not used Table 7 STA Response Codes The command STA causes the TWTA to send a string indicative of the current system state STA response Meaning SLEEP Sleep Mode active heater off WARM UP System is in heater time delay STANDBY System is ready to allow high voltage on OPERATE High voltage is on and beam is on FAULT High voltage is off and system requires reset Rev B 21 Model 20T4G18 Table 8 STB Response Codes The command STB causes the TWTA to send a string containing an operational state code consisting of 2 ASCII characters representing hex digits The response is in the form STATUS x y eol where the hex values of and y are formed as shown below x bit Meaning 1 Mode switch always 1 reset 2 Blank switch always 1 off 3 Blank status always 0 off 4 Not used always 0 y bit Meaning 1 Power status
60. te procedure is to pre set the TWTA gain to minimum set the RF generator to 0 dBm and then slowly increase the TWTA gain to set the desired RF output level Observe that the helix current is sensitive to the RF drive level of the TWT It is at a minimum with no RF drive The helix currents with no drive and with rated RF output mid band are logged on the test data sheet The value of the helix current is a good gualitative indicator of RF drive present To shut the system down turn down the RF generator level below 50 dBm and press STANDBY Allow the TWTA to cool down until the TWT temperature drops below 709 then turn off main power 3 7 EMERGENCY BYPASS OPERATION For reference see schematic 10 24830 002 in section 5 2 The TWTA is provided with a means of operating the amplifier manually in the event that there is a failure of the control module and it is imperative that the amplifier remain on line CAUTION Emergency bypass operation disables certain protective and diagnostic A features For this reason the emergency bypass mode of operation should be used only when the control unit fails and when it is essential to remain on line To access the manual controls remove the two 4 40 screws securing the emergency switch cover on the front panel Emergency bypass mode is selected by pushing the left hand switch S1 to the left The center switch S2 toggles between high voltage on left and high voltage off right The right hand sw
61. ts excess reflected power warning and remote Standard features include a built in IEEE 488 GPIB interface OdBm input VSWR protection gain control RF output sample port auto sleep plus monitoring of TWT helix current cathode voltage collector voltage heater current heater voltage baseplate temperature and cabinet temperature Modular design of the power supply and RF components allow for easy access and repair Use of a switching mode power supply results in significant weight reduction Housed in a stylish contemporary cabinet this unit is designed for benchtop use but can be removed from the cabinet for rack mounting The Model 20T4G18 provides readily available RF power for a variety of applications in Test and Measurement including EMC RF susceptibility testing Industrial and University Research and Development and Service applications 20T4G18 TYPICAL POWER OUTPUT 10 12 14 16 18 20 FREQUENCY GHz REV111804 SPECIFICATIONS Model 20T4G18 POWER fundamental CW OUTPUT CONNECTOR IO A MU RU RE 42 watts WII UM 20 watts Linear IdB Compression eere eee eee eite ee in ie rece 10 watts minimum FLATNESS m 9 dB maximum 4 2 18 GHz 5dB maximum 8 0 18 GHz FREQUENCY RESPONSE eee eene eee tnnt s
62. worldwide Operating and Service Manual 90T4G18 Model 1008254 501 Part Number Serial Number ar worldwide gt rf microwave instrumentation 160 School House Road Souderton PA 18964 9990 215 723 8181 Fax 215 723 5688 www ar worldwide com Model 20T4G18 worldwide EC Declaration of Conformity We Amplifier Research 160 School House Road Souderton PA 18964 declare that our product the Model 200T4G18 amplifier to which this declaration relates is in compliance with the requirements of the EEC EMC Directive 89 336 EEC and Low Voltage Directive 73 23 EEC in accordance with the relative standards listed below EMC EN 50082 1 1992 Electromagnetic compatibility Generic immunity standard EN 50081 1 1992 Electromagnetic emissions requirements for Industrial Scientific and Medical ISM Equipment Safety EN 60950 1995 The CE marking is affixed on the device according to the EC Directives QAR AMI Donald R Shepherd President Model 20T4G18 A BEFORE APPLYING POWER Review this manual and become familiar with all safety markings and instructions Verify that the equipment line voltage selection is compatible with the main power source Protection provided by the equipment may be impaired if usedin a manner not specified by Amplifier Research INTENDED PURPOSES This equipment is intended for general laboratory use in a wide variety of industrial and scientific applications

AMPLIFIER RESEARCH 20T4G18 Operating

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