Handbook of Operating Instructions for Radio
Contents
1. 08 405 8729 2 2583A HANDBOOK OF OPERATING INSTRUCTIONS for RADIO SETS SCR 729 A and SCR 729 AZ NOTE This handbook replaces T O No 08 10 167 dated 10 May 1943 and revised 8 July 1943 RESTRICTED For Official Use Only RESTRICTED 08 405 729 2 Published under joint authority of the United States War and Navy Departments and the Air Council of the United Kingdom SECURITY NOTICE FOR U 5 PERSONNEL This document contains information affecting the national defense of the United States within the meaning of the Espionase Act 50 U S C 31 and 32 as amended Its transmission or the revelation of its contents in any manner to an unauthorized person is prohibited by law AR 380 5 ARTS 7514 amp 76 5 REGS 1920 The information contained in restricted documents and the es sential characteristics of restricted materiel will not be communi person known to be in the service of the United States and to persons of undoubted loyalty and discretion who are cooperating in Government work FOR BRITISH PERSONNEL For Official Use Only Not to be communicated to anyone outside His Majesty s Service Not to be published The information given in this document is not to be communicated either directly or indirectly to the press or to any person not holding an official position in His Majesty s Service cated to the public or to the press but may be given to any LIST OF REVISED PAGES I2. witch Swe Se Hmmm Em Ae T AL GA 9 5 ohm resistor must be substituted as a dummy load Connect this resistor from the center con ductor of the TRANS ANT socket to the chassis This resistor is shown in schematic figure 24 1 INSTALLATION a GENERAL Installation of Radio Set SCR 729 A RESTRICTED 3 Section RESTRICTED 08 40SCR729 2 147 22 SUPPRESSOR A C IN am OUT 3 Ms AN3102 18 3P S LZ A N3I02 18 35 3 02 165 48 _ 1 AN3IO2 165 4P 310848 35 AN3IOB 18 3P E 3108 165 45 3108 18 35 3108 165 45 1145 AN3IO2 22 17P o 22 17 929 MONDE Un a e 115v a C 24 v 0 A C POWER POWER SOURCE SOURCE CENTER CONDUCTOR ey 1 k X UKE oe AA NT vF 7 Figure 8 Coaxial Cable Connections fo 2 Antenna AN 148 A Receiving Antenna AN 148 A 4 RESTRICTED RESTRICTED 08 40SCR729 2 18 made according to the cording diagram figure 6 De tails of the antenna installation are given in figure 7 and the method of connecting the coaxial transmission lines to the receiving antennas is shown in figure 8 Details for making up the coaxial cables power cable and con trol cable are given in figures 9 10 and 11 b RA
3. Date placed in service Part which failed Nature and cause of failure Replacement needed yes no Remedy used or proposed to prevent recurrence For British Personnel Form 1022 procedure should be used when reporting failure of radio equipment RESTRICTED ii 08 40SCR729 2 V 664 42S 4195 jo Sjusuodwo 3inbij 5 11 28 08 1081 02 O10VY 917 13 ONILNNOW V 666 28 YOLVIIGNI V 008 28 YILLINSNVUL 3 43A13333 O1dVY RESTRICTED iv RESTRICTED 08 40SCR729 2 Section Paragraphs 1 3 SPECIAL NOTICE References in illustrations and text of this handbook are made only to Radio Set SCR 729 A However ail references to Radio Set SCR 729 A apply equally to Radio Set SCR 729 AZ except where an asterisk 5 calis attention to special differences SECTION GENERAL DESCRIPTION 1 INTRODUCTION a Radio Set SCR 729 A is a complete airborne radio receiver and transmitter with an indicator or display unit The indicator is used to show the signal from the receiver The receiver is designed to receive on either one of two preset frequencies the transmitter on one preset frequency b The radio set operates either independently with Indicator BC 929 A or as an auxiliary with display units of such radio sets as Radio Sets SCR 517 B SCR 517 C SCR 520 A SCR 520 B SCR 717 A SCR 717 B SCR 720 SCR 540 A SCR 521 A etc c Components of the
4. MOUNTING FT 409 A RECEPTACLE RECEPTACLE Figure 3 Indicator BC 929 A 2 RESTRICTED RESTRICTED Sections 1 1 08 40SCR729 2 MOUNTING 406 RECEIVER FREQUENCY SWITCH RECEPTACLE Be AN3102 22 17P alter eA aetna manner n MEME EE Figure 4 Radio Control Box BC 1145 A 4 POWER REQUIREMENTS 4 GENERAL Radio Set SCR 729 A requires 24 volts direct current and 115 or 80 volts alternating current at a frequency from 400 to 2400 cps for a power source This power is supplied from either the auxiliary equipment or from a separate inverter depending upon the type of installation Components normally are con nected for 115 volt operation However taps have been provided on the power transformer of Indicator BC 929 A and the two power transformers of Radio Receiver and Transmitter BC 800 A for 80 volt a c operation The correct power connections should be made upon installa tion of the equipment in the plane A check of the tap connections should be made if any part of Radio Set SCR 729 A is changed See figure 5 for the connections POWER REQUIREMENTS OF TS n D i A C M ETT oe MM i Volts Amperes Volts Wans PET Siege wea si EA cs DERE
5. e Disconnect Plug PL 259 from the socket marked VIDEO on Radio Receiver and Transmitter BC 800 A and connect it to the socket marked TRANS ANT on Radio Receiver and Transmitter BC 800 A These changes in cording should arrange the equipment as shown in figure 25 RANGE CALIBRATOR 000 AR pa M e GERE 63 RADIO RECEIVER p TRANSMITTER BC 800 A ANTENNA RADIO CONTROL BOX 1145 H ER RE Re aR ROREM PLUG Pl 259 2 CORD 0 800 3 CORD CD 799 Figure 24 Indicator BC 929 A Calibration Check Cording Diagram RESTRICTED 13 Section Il Paragraph 2 1 Turn on Radio Set SCR 729 A and throw the toggle switch on Indicator BC 936 A to the POWER position g Using the CENT control on Indi cator BC 929 A shift the base line of the signal to the right hand vertical line on the screen See figs 14 and 28 5 Turn on Indicator BC 936 A by pressing mo mentary contact switch marked PUSH The transmitter signal will now appear at the zero line on the display tube of Indicator BC 929 A The tip of the signal should extend at least four and one half scale divisions to the left as shown in figure 15 This is an indication of minimum allowable power output i Reset the base line of the signal to the center line of the sc
6. Radio Keceiver and 24 1 05 ilis 135 138 Transmitter BC 800 A 400 2400 cps TE Indicator 929 24 0 5 jii5vols 40 42 1400 2400 od Radio Receiver and 12 L0 1115 volts 135 138 Transmitter BC 800 AZ 400 2400 indicator BC 929 AZ 12 L 1115 ve alts 40 42 i ES X E 24 i cps Jim Ere cec D eee SCR 729 AZ requires 12 volts direct current TOWER TRANSFORMER be We ii5v 80V D 9 i Q INDICATOR f oS on RECEIVER TRAN SMITTER bai FILAMENT fey d TRANSFORMER o Ay l E Ls ovd 0 dq RECEIVER qm OMA NI TRANSMITTER 5 HIGH VOLTAGE 4 TRANSFORMER j TES G i 1 A EPE EAP A A ENE ET MLa eg at EENE Figure 5 Transformer Connections SECTION Ii INSTALLATION AND ADJUSTMENT CAUTION TRANS ANT socket on Radio Receiver and Transmitter BC 800 A must be connected to a proper load to avoid immediate failure of tube 2C26 when the power egeo on Control Box BC 1145 A is turned on If the transmitting antenna is not connected a 50 transmitting t 1
7. a receiver gain control and a frequency selector switch The ON OFF cuntch rantenlie the nawar ta the receirvor trancmitter OYvilVii CULL LEER pUYVCL LU UIT AREER ELE the indicator and also the d c power in the receiver transmitter The DI IR switch has three positions namely DI for constant operation IR for momen tary operation and a center position for standby opera tion The GAIN control adjusts the output of the receiver The HIGH LOW switch controls the fre quency of the receiver See figure 4 for an illustration of this unit d ANTENNA AN 148 A RECEIVING Anten AN 14Q ic a wartical dinala with a divrartar mauntad 4 71 07143 13 A ai VIRA VV ELER A MELAS inountca on a single standard with a bakelite housing There are two of these antennas used on each installation one on each side of the fuselage with the director pointing toward the nose of the plane e ANTENNA AN 147 A TRANSMITTING Antenna AN 147 A consists of a dipole made of two quarter wave rods mounted one on each side of the front of the fuselage in a horizontal position Adapter M 358 and Plug PL 258 are used to connect the trans mitter output to each of the antennas Cord lengths are critical from Adapter 258 to each of Antennas AN 147 A For complete information refer to Handbook of Maintenance Instructions for Radio Set 5 729 or SCR 729 AZ and Test Equipment IE 56 A
8. consists of Signal Generator mm Ok rqui AR RE RPL LER RR I 196 B Test Radio Receiver BC 1066 B not eek Frequency Meter BC 906 D Range Caltbrator 949 Power Indicator BC 936 A two Cords CD 800 and one Cord CD 799 See fig 18 Use Frequency Meter BC 906 D to calibrate Signal Generator 1 196 B and to adjust the transmitter frequency of Radio Receiver and Transmitter BC 800 A Use Signal Generator 1 196 B to check the frequency of the receiver of Radio Receiver and Transmitter BC 800 A Use Range Calibrator BC 949 A to calibrate the screen of Indicator 929 Use Indicator BC 936 A to check the power output and signal duration width of the transmitter signal of Radio Receiver and Transmitter 800 Radio Receiver BC 1066 B need not be used 2 PREPARATION OF TEST EQUIPMENT 1 56 a To calibrate Signal Generator 1 96 place the signal generator next to Frequency Meter BC 906 D 6 Insert the collapsible antenna into the recep tacle marked ANTENNA on top of Frequency Meter BC 906 D Be sure the antenna 1s tended its full length c Set the HI LO switch on the frequency meter to LO and throw the ON OFF switch to the position d Set the dial of the frequency meter to the high frequency calibration point given by the Communi cations Officer in Charge for the setting of the receiver of Radio Receiver and Transmitter B
9. for Power Output Check Figure 30 Pulse Width Signal Statute Scale Figure 31 Calibration Signal Statute Scale RESTRICTED 15 Sections I IV RESTRICTED AN 08 40SCR729 2 SECTION OPERATION CAUTION TRANS ANT socket on Radio Receiver and Transmitter BC 800 A must be connected to a proper load to avoid immediate failure of trans mitting tube 2C26 when the power switch on Control Box BC 1145 A is turned on If the transmitting antenna is not connected a 50 ohm resistor must be substituted as a dummy load Connect this resistor from the center con ductor of the TRANS ANT socket to the chassis This resistor is shown in figure 24 1 STARTING THE EQUIPMENT With the DI IR switch on Control Box BC 1145 A in the mid position turn ON OFF switches on Ra dio Control Box BC 1145 A and on Indicator BC 929 A to ON positions 5 Check that the blower operates c Wait 3 minutes for warm up period d Turn the DI IR switch in DI position and the receiver GAIN control to maximum clockwise posi tion Adjust the FOCUS and INTENSITY controls on Indicator BC 929 A for a clear trace See fig 13 e Adjust the receiver GAIN control on Radio Con trol Box BC 1145 A to proper level f Place the HIGH LOW switch to the selected position IMPORTANT Further use of the HIGH LOW switch and the DI IR switch depends upon the nature of t
10. for tuning the receiver oscillator while in flight The new equipments will be interchangeable with the old equip ments in all respects b INDICATOR BC 929 A Indicator BC 929 A is used to show the signal received by the receiver section of Radio Receiver and Transmitter BC 800 A The panel of the indicator has sockets for the right and left receiv ing antenna input the receiving antenna output video input sync input and power connections It also provides a viewing screen for one cathode ray indicator tube There are eight screwdriver adjustments on the front panel One of these adjustments is for horizontal center ing and one is for vertical centering of the image on the indicator screen Three adjustments are used for adjust ing sweep duration one for each setting of the range switch and the remaining two for adjusting the ampli tude of the trace for each range The three knobs on RESTRICTED AN 08 40SCR729 2 the lower part of the panel marked INTENSITY RANGE and FOCUS are used to adjust the in tensity of the image on the indicator screen to select one of three ranges covered by the equipment and to adjust the focus The ON OFF switch turns on the d c power for operating the motor switch in the indicator See figure 3 for an illustration of the indicator panel c RADIO CONTROL BOX BC 1145 A Radio Control Box 1145 contains switches to turn on the components of Radio Set SCR 729 A
11. frequency meter The transmitter tuning adjustment is reached through a window marked TRANS FREQ on the front panel of Radio Receiver and Transmitter BC 800 A 5 INDICATOR CALIBRATION CHECK NAUTICAL MILES a To check the calibration of Indicator BC 929 A a signal from Range Calibrator BC 949 see fig 22 is fed to Indicator 929 which is adjusted at each of the three ranges for correct calibration b Disconnect Plug PL 259 from the socket marked SYNC on Indicator BC 929 A and connect it to the socket marked SYNC INPUT on Range Cali brator BC 949 A See fig 24 c Connect Plug PL 259 on one end of Cord RECEPTACLE AN3102 18 3P RECEPTACLE 3102 18 35 1 RANGE SWITCH Figure 22 Range Calibrator 949 RESTRICTED NI Aa 11 Section Il Paragraph 2 VIDEO OUTPUT PJ TRANSMITTER INPUT Figure 23 Indicator BC 936 A CD 800 to the socket marked SYNC OUTPUT on Range Calibrator BC 949 A and connect Plug PL 259 on the other end to the socket marked SYNC on Indicator BC 929 A d Disconnect Plug PL 259 from the socket marked VIDEO on Indicator BC 929 A e Using the other cord CD 800 connect the socket marked VIDEO on Indicator BC 929 A to the socket marked VIDEO OUTPUT on Range Calibrator BC 949 A RESTRICTED 08 40SCR729 2 43 TMeonamnsrnrt the Ger Asconnec t the power plug from its socket on Indicator BC 929
12. shield of all these coaxial cables is grounded through the co axial connector See fig 9 Cords carrying the power for the radio set are made from standard aircraft power and lighting cable See figs 10 and 11 The length of the various cables differs with each type of airplane installation When cordage is made up for connecting the com ponents of the radio set each cable must have sufficient length to allow for maximum movement of the com ponents on their shock mounts thus preventing damage to the connector Leave sufficient slack when clamping cords to the structure of the airplane If cords are clamp ed tightly friction may cause troublesome breaks and wear in insulation CAUTION Do not operate the equipment unless the trans mitting antenna is connected properly or a dummy resistance load of 50 ohms is connected between the center conductor of the coaxial socket marked TRANS ANT and ground Otherwise the transmitting tube will be damag RESTRICTED Section 1 Paragraphs 1 2 ed Plug PL 259 with a 50 ohm resistor con nected between the inner conductor and the outside of the plug is a satisfactory dummy load b INSTALLATION INSPECTION 1 Check all antennas for secure mounting and electrical connections Check receiving antenna input for proper balance 2 Check each cord for mechanical wear and sible breaks 3 Check each cord for electrical connections and shorts 4 Check the plugs and socke
13. 48 A Receiving 3 3 Receiver Frequency Check e Antenna AN 147 A Transmitting 3 4 Transmitter Frequency Check 4 Power Requirements 3 5 Indicator Calibration Check General orbata dd 3 Nautical Miles I b Power Requirements of Components 3 6 Indicator Calibration Check and Adjus Mile Scale INSTALLATION AND ADJUSTMENT 3 ic aaa dC 7 Power Output Check Installation AA 3 i General uso step EE aus UU 3 HI OPERATION 5 Radio Receiver and Transmitter BC 800 5 g c Indicator 929 5 2 Stopping the Eguipment d Radio Control Bor BC 1 5 IV EMERGENCY REPAIR 2 B e Antennas AN 148 A Receiving 5 f Antennas AN 147 A Transmitting 5 D General vous TIPP g Cording and Cables 5 Common Troubles and Their Corrections RESTRICTED AN 08 405 729 2 TABLE OF CONTENTS RESTRICTED bases ei 1 4 16 bun e RESTRICTED AN 08 40SCR729 2 LIST OF ILLUSTRATIONS Figure Page 1 Components of Radio Set SCR 729 A iv 2 Radio Receiver and Transmitter BC 800 A 1 3 Indicator BC 929 A 1 4 Radio Control Box BC 1145 A 2 5 Transformer Connections 2 6 Cording ue uoo E dete 4 7 Left Si
14. A a connect it to the socket marked A C IN on Range Calibrator BC 949 A Con nect one end of Cord CD 799 to the remaining socket on Range Calibrator BC 949 A and the other end to the wA enrbat Aan Te Rr 090_A pev SULA ULI ARIIVIJLGLUARL AW Hote Make sure proper load is connected to TRANS ANT See fig 24 Tress With the DI IR switch in the mid position turn on Radio Set SCR 729 A and allow 3 minutes for warm up Place the DI IR switch on Radio Control Box BC 1145 A to the DI position and set the range switches on Range Calibrator BC 949 A and Indicator BC 929 A to the position marked 10 The display tube of Indicator BC 929 A will now show a wavy line sym metrically located on both sides of the vertical center line The points used in calibration are the points of minimum horizontal width For each range there are ten ah 432437 calibration points SO 10 mile will have two calibration points every 2 miles See fig 17 b Align the indicator by using the vertical cen tering control VER CENT on Indicator BC 929 A to place the 2 mile calibration point on the 2 mile hori zontal line The 8 mile calibration point should then fall on the 8 mile horizontal line If it does not make a screwdriver adjustment on the sweep amplitude control marked 10 Indicator BC 929 A until it does 7 A slight readjustment of
15. C 800 A e Insert the plug of the headset into the PHONE jack of Signal Generator 1 196 B f Turn on the signal generator 155 tone in the headset g Adjust the knob of Signal Generator 1 196 B marked LO I G HI until maximum dip is observed on the meter of Frequency Meter BC 906 D Note this point on the signal generator dial which is the receiver high frequency calibration point tening for its b Repeat steps a g at the receiver low frequency calibration point i Repeat steps 4 6 at the mid point fre gh low quency of the receiver hi eX 5 2 5 3 ERR Es w frequency calibration points 3 RECEIVER FREQUENCY CHECK The 400 2400 input voltage to the equip ment should be kept between 110 and 120 volts for the following adjustments RESTRICTED 9 Section 11 Paragraph 2 4 Use Signal Generator 1 196 to send the signals used in calibrating the receiver of Radio Receiver and Transmitter BC 800 A When the receiver is tuned to the frequency of the signal generator maximum sig nal display will be observed on the indicator screen b Turn on and adjust Signal Generator 1 196 B to the mid point of the high low frequency calibration points as determined in paragraph 26 4 i this section and place it about 25 feet in front of the airplane in which Radio Set SCR 729 A is installed c With the DI IR switch in mid position turn the power ON OFF switches of Radio Set SC
16. DIO RECEIVER AND TRANSMITTER 800 A Mount receiver and transmitter so that the side containing the sockets and frequency adjustments is easily accessible while viewing the indicator screen INDICATOR BC 929 A Mount the indicator so that the cathode ray tube may be viewed while operating the radio equipment with which Radio Set SCR 729 A is associated d RADIO CONTROL BOX BC 1145 A Place the radio control box so that it is easily accessible at all times without the operator having to move from his regular operating position ANTENNAS 148 RECEIVING Mount the two receiving antennas on opposite sides of the fuse lage near the nose of the airplane so that maximum use of their directional characteristics is achieved See fig 7 Coaxial cable connections are shown in figure 8 f ANTENNAS 147 TRANSMITTING Place the two transmitting antennas on opposite sides of the fuselage toward the front of the airplane See fig 7 Adaptor M 358 and Plug PL 258 are used to apply the output signal of the transmitter to both antennas See fig 6 8 CORDING AND CABLES All cordage for con necting the components of the radio set should be cut and connected carefully See figs 6 9 10 and 11 Cords used for antennas are made up of Cable RG 8 U Cables for carrying the video and synchronizing voltages between the various components and to the associated equipment shall be made of Cable RG 8 U The
17. Handbook of Mainte nance Instructions for Radio Set SCR 729 A or SCR 729 AZ and Test 1 56 3 3 a e fh fCAnnert shan Prr UDI MTT 77 UIL term ak AAS VEX GALAN on Indicator BC 929 A to terminal marked ANT TEST on Frequency Meter BC 906 D See fig 21 Cord CX 16 TPN 1 is used to make this con nection and is furnished as auxiliary equip ment Cord CX 16 TPN 1 may be made by placing Plug PL 259 or PL 259 A and coupling Section Paragraph 2 MC 277 on the ends of a 3 foot length of coaxial cable c Place the DI IR switch in the standby mid position Make sure there is an antenna load or 50 ohm dummy Place the ON OFF switches on Con trol Box BC 1145 A and Indicator BC 929 A in the position Allow 3 minutes for the set to warm up d Place the DI IR switch on the control box to the DI position e Turn the ON OFF switch on the frequency meter to the position and rotate the dial for the greatest dip of the needle The dial position number should be that corresponding to the correct transmitter frequency f If it is found that the transmitter frequency is incorrect set the dial of the frequency meter to the position number corresponding to the desired trans mitter frequency 8 Using a fibre screwdriver adjust the trans mitter frequency for the greatest dip of the needle on the
18. R 729 located on Radio Control Box BC 1145 A and on Indicator BC 929 A to the ON position After a 3 minute warm up turn the DI IR switch on Control Box BC 1145 A to the DI position Turn the RANGE switch of Indicator BC 929 A to 100 Al low the radio set to warm up for several minutes d Turn the receiver HIGH LOW switch on Radio Control Box BC 1145 A to HIGH See fig 4 Watch the tube of Indicator BC 929 A for an indication that the signal from the signal generator is received when the HIGH RCVR OSC tuning shaft is turned with a fibre screwdriver This adjustment is reached through an opening in the front panel of Radio Receiver and Transmitter BC 800 A See fig 2 Adjust the receiver GAIN control until a signal of about 15 maximum amplitude is observed on the display tube e Adjust the HIGH RCVR OSC control on Radio Receiver and Transmitter 800 for maximum signal amplitude on the indicator screen f Unlock the screw with the locking washer under each of the receiver tuning adjustments 1 2 3 located on the front panel of Radio Receiver and Trans mitter BC 800 A g Tune receiver tuning adjustments 1 2 3 for maximum signal on the display tube Hote If no signal appears on the display tube move the signal generator close to the receiver an tenna for preliminary adjustment 5 Repeat steps d and f for an accurate setting i Tighten locking nuts on the re
19. SSUED NOTE A heavy black vertical line to the left of the text on revised pages indicates the extent of the revision This line is omitted where more than 50 percent of the page is revised THIS ISSUE CONTAINS NO REVISIONS ADDITIONAL COPIES OF THIS PUBLICATION MAY BE OBTAINED AS FOLLOWS AAF ACTIVITIES Submit requisitions to the Commanding General Fairfield Air Service Command Patterson Field Fairfield Ohio Attention Publi cations Distribution Branch in accordance with AAF Regulation No 5 9 Also for details of Technical Order distribution see T No 00 25 3 NAVY ACTIVITIES Submit requests to the Chief Bureau of Aeronautics Navy Department Washington D C BRITISH ACTIVITIES Submit requirements on Form 294A in duplicate to the Air Publications and Forms Store New College Leadhall Lane Harro gate Yorkshire England RESTRICTED Section Page Section Pa 1 GENERAL DESCRIPTION 1 b Installation Inspection I Introduction s ios ise SURE A 1 2 ENG ISETIGBE AI AA 2 Principal Components KAWE 1 Preliminary Operation Check 3 Description of Principal Components 222 Pests ioca ales Radio Receiver and Transmitter BC 800 A 2 1 General tna To b Indicator BC 929 A 3 2 Preparation of Test TA WAM c Radio Control BC 11 5 A 3 4 Antenna AN 1
20. cale 15 SAFETY NOTICE This equipment employs high voltages which are dangerous and may be fatal if contacted by operating personnel Extreme caution should be exercised when working with the equipment RESTRICTED RESTRICTED AN 08 405CR729 2 Destruction of Abandoned Materiel in the Combat Bone In case it should become necessary to prevent the capture of this equipment and when ordered to do so DESTROY IT SO THAT NO PART OF IT CAN BE SALVAGED RECOGNIZED OR USED BY THE ENEMY BURN ALL PAPERS AND BOOKS Means 1 Explosives when provided M 7 2 Hammers axes sledges machetes or whatever heavy object is readily available 3 Burning by means of incendiaries such as gasoline oil paper or wood 4 Grenades and shots from available arms 1 5 Burying all debris or disposing of it in streams or other bodies of water where possible and when time permits Procedure p Obliterate all identifying marks Destroy nameplates and circuit labels Demolish all panels castings switch and instrument boards Destroy all controls switches relays connections and meters Rip out all wiring and cut interconnections of electrical equipment Smash gas oil and water cooling systems in gas engine generators etc Smash every electrical or mechanical part whether rotating moving or fixed Break up all operating instruments such as keys phones microphones etc Destroy all classes o
21. ceiver tuning adjustments marked 1 2 3 Check that the setting does not shift as these nuts are tightened 7 Tune Signal Generator 1 96 B to the high frequency calibration point as determined in paragraph 26 4 g this section and place it 25 feet in front of the airplane k Adjust the RCVR OSC tuning shaft mark ed HIGH for maximum signal on the indicator screen with the HIGH LOW switch on the control box set to the HIGH position Do not change the receiver tuning adjustments Repeat the above procedure for an accurate setting After the correct setting has been ob RESTRICTED AN 08 40SCR729 2 tained do not change the HIGH RCVR OSC tuning adjustment L Set Signal Generator 1 196 B to the low fre quency calibration point as determined in paragraph 2b 4 b this section With the HIGH LOW switch on the control box in the LOW position adjust the RCVR OSC tuning shaft marked LOW for maxi mum output on the indicator screen Repeat the above procedure for an accurate setting After the correct set ting has been obtained do not change the LOW RCVR OSC tuning control m Place Signal Generator 1 196 approximate ly 50 to 75 feet to the right of the airplane at an angle of 45 degrees from the center line The signal generator must always be set with the side nearest the nameplate facing the airplane The signal amplitude on the right side of the display tube of Ind
22. de of Airplane showing 1 Antenna AN 147 A and 2 Antenna AN 148 A 4 8 Coaxial Cable Connections to Receiving Antenna AN 148 A 4 9 Coaxial Cable Diagram 5 10 Power Cable Diagram 6 11 Control Cable Diagram 6 12 Sweep Trace Nautical Scale 7 13 Hash Nautical Scale y 14 Sweep Trace Nautical Scale Set for Power Output Check 7 15 Power Output Nautical Scale 7 ii Figure 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Page Pulse Width Nautical Scale 7 Calibration Signal Nautical Scale 7 Components of Test Equipment IE 56 A 8 Signal Generator I 196 B Panel View 9 Frequency Meter BC 906 D 10 Cording Diagram of Transmitter Frequency eius 11 Range Calibrator BC 949 A 11 Indicator BC 936 A 12 Indicator BC 929 A Calibration Check Cording Diagram 13 Power Output Check Cording Diagram 14 Sweep Trace Statute Scale 15 Hash Statute Scale 15 Sweep Trace Statute Scale Set for Power Output Check 15 Power Output Signal Statute Scale 15 Pulse Width Signal Statute Scale 15 Calibration Signal Statute S
23. f carrying cases straps containers etc Bury or scatter all debris DESTROY EVERYTHING op WY 00 14 Unsatisfactory Report For S Army Air Force Personnel In the event of malfunctioning unsatisfactory design or unsatisfactory installation of any of the com ponent units of this equipment or if the material contained in this book is considered inadequate or erron eous an Unsatisfactory Report AAF Form No 54 or a report in similar form shall be submitted in accord ance with the provisions of Army Air Force Regulation No 15 54 listing Station and organization Nameplate data type number or complete nomencla ture if nameplate is not attached to the equipment Date and nature of failure Airplane model and serial number Remedy used or proposed to prevent recurrence 6 Handbook errors or inadequacies if applicable For U 5 Navy Personnel Report of failure of any part of this equipment during its guaranteed life shall be made on Form N Aer 4112 Report of Unsatisfactory or Defective Material or a report in similar form and forwarded in accordance with the latest instructions of the Bureau of Aeronautics In addition to other distribution re quired one copy shall be furnished to the inspector of Naval Materiel location to be specified and the Bureau of Ships Such reports of failure shall include Reporting activity Nameplate data
24. he mission 1 If the equipment is to be used for constant operation set the DI IR switch to the DI position 2 If the equipment is to be used for momen operation hold the DI IR switch in the IR position It will not remain in this posi tion unless held A coded message may be sent by use of this switch or if it is desired to stop the sensing switch on the indicator the OFF switch on the indicator can be turned off 2 STOPPING THE EQUIPMENT To stop the equipment turn off the ON OFF switches on Indicator BC 929 A and Radio Control Box BC 1145 A SECTION IV EMERGENCY REPAIR 1 GENERAL a After a new installation or a change in equipment make the installation inspection as discussed in section paragraph 14 Check the transformer tap connections Make an operation test to secure correct function of components Refer to sec par 24 b To prepare for a mission make a brief installation check Check and adjust the receiver and transmitter Observation frequencies c After each week of average flying time make a complete installation and operation check Refer to sec II pars 1 2 2 COMMON TROUBLES AND THEIR CORRECTIONS Listed below is a trouble chart giving suggested remedies Remedy 16 Blower motor does not operate No spot on screen of Indicator BC 929 with INTENSITY control turned to the extreme clockwise position Spot on indicato
25. icator BC 929 A should be greater than the signal on the left side 2 Repeat step 72 with the signal generator to the left side The received signal should now have great Figure 20 Frequency Meter BC 906 D 10 RESTRICTED RESTRICTED 08 405CR729 2 Figure 21 Cording Diagram of Transmitter Frequency Check er amplitude on the left side of the trace line on Indicator BC 929 A In order to determine whether or not the receiver antenna systems are properly balanced set Sig nal Generator 1 196 approximately 25 feet in front of and directly in line with the center of the airplane The signal generator must be set with the side nearest the name plate facing the airplane If the signals are of equal amplitude on both sides of the time base line of the cathode ray tube the receiving antenna system is satis factorily balanced for homing This test must be made with the aircraft in an open area to avoid signal reflec tions from nearby objects The propellers on each side of the aircraft must be placed in similar positions 4 TRANSMITTER FREQUENCY CHECK The antenna load often affects the transmitter frequency Therefore the transmitter frequency should be adjusted after the equipment has been installed in the airplane a Obtain the frequency code number on the chart of Frequency Meter BC 906 D which corresponds to the transmitter frequency from the Communications Officer in Charge or from the
26. igure 10 Power Cable Diagram RELAY BIAS GROUND GAIN BLOWER 24 VOLT D C 15 VOLT A C 15 VOLT A C 150 VOLT D C AN 3108 22 17 AN3I08 22 178 Figure 11 Control Cable Diagram 6 RESTRICTED RESTRICTED Section li 08 40SCR729 2 Figure 14 Sweep Trace Nautical Scale Set Figure 15 Power Output Nautical Scale for Power Output Check E gt Figure 16 Pulse Width Nautical Scale Figure 17 Calibration Signal Nautical Scale RESTRICTED 7 RESTRICTED 08 405 729 2 Section 9 31 Juawdinbj 1591 jo sjusuodwo V 9 6 2H SOIVOIGNI 4 906 28 0 44 H 961 I NOIVNSNS3O TYNOIS 8 008 6 6 28 NOIVNSITYO 9901 28 41 14244 OIGVM RESTRICTED RESTRICTED AN 08 405CR729 2 CAUTION Make sure that the transmitting antennas are connected or that a 0 ohm dummy load is con nected to the TRANS ANT socket on BC 800 A before turning on the equipment Imme diate failure of the transmitting tube will result otherwise 13011161 Wise 6 With the DI IR switch in the center position throw the ON OFF switch on Radio Control Box BC 1145 A and on Indicator BC 929 A to the ON posi tion A should appear on the indicator tube but there will be no sweep trace except in early sets 7 Make sure that the blowe
27. m figure 6 Hote Do not alter SWEEP DURATION or SWEEP AMPLITUDE adjustments unless actually making adjustments using Range Cali brator BC 949 A 6 INDICATOR CALIBRATION CHECK AND ADJUSTMENT FOR STATUTE MILE SCALE a Normally the range scale of the mask over the screen of the cathode ray tube of Indicator BC 929 A is calibrated in nautical miles However a mask calibrat ed in statute miles is provided in an envelope attached to the switching motor inside the indicator b The procedure for calibrating the statute mile scale is identical to that given for the nautical mile scale except that the lower dotted line is used in place of the 10 2 range line and the upper dotted line is used in place of the 40 8 range line See figs 26 31 Section Il Paragraph 2 7 POWER OUTPUT CHECK 4 Check the power output of the transmitter of Radio Receiver and Transmitter BC 800 A by applying the output signal of the transmitter to Indicator BC 929 A through Indicator BC 936 A 5 With Radio Set SCR 729 A turned dis connect Plug PL 259 from the socket marked TRANS ANT on Radio Receiver and Transmitter BC 800 A c Disconnect Plug PL 259 which is connected to the socket marked VIDEO on Indicator BC 929 A and connect it to the socket marked TRANS IN on Indicator BC 936 A d Connect the cord from Indicator BC 936 A marked VIDEO OUT to the socket marked VIDEO on Indicator BC 929 A
28. r is in operation 8 Allow the set to warm up for 3 minutes and then turn the Dr IR switch on Radio Control Box BC 1145 to the DI constant operation position 9 Adjust the FOCUS and INTENSITY con trol on Indicator BC 929 A for a sharp and clear trace line as indicated in figure 13 10 With the GAIN control on the control box in the maximum clockwise position the receiver is oper ating if a band of hash appears on the trace line of the indicator tube See fig 15 The transmitter 1s operating if a pulse appears at the bottom of the sweep See fig 13 Note Radio Set SCR 729 A is used at times with other similar radio equipment When other equipment is used check the operation of this nm Aud xm qx cq de v PT XU IQ RUE Eq rc uperatutvui b FIELD TESTS 1 GENERAL a Complete and detailed information as to fre SIONAL 8181 441864 1 13 aet ran vi 4 CAUTION in TURN SWITCH OFF WHEN 9 NOT IN USE A OFF Panel View Figure 19 Signal Generator 1 196 8 Section 1l Paragraph 2 quencies and adjustments are included in the Handbook of Maintenance Instructions for Radio Sets SCR 729 and SCR 729 AZ and Test Equipment IE 56 A or it may be obtained from the Communications Officer 1n Charge b Use Test Equipment 56 to check Radio Set SCR 729 for operation and frequency coverage Test Y eei ent YE
29. r tube but no trace line Hash but no signal Signal or indicator abnormal Cord disconnected Indicator BC 929 A faulty cords dis connected or broken Faulty cord and connection to the transmitter and receiver Receiver transmitter not operating correctly Bad antenna connections Transmitter output weak or no output Bad cord connections N OFF switch on Indicator BC 929 in OFF position Output from Radio Receiver and Transmitter BC 800 A faulty Indicator BC 929 A not functioning properly RESTRICTED Check cord Check all cording If still faulty re place Indicator BC 929 A Check the sync cords from Radio Re ceiver and Transmitter BC 800 A Replace Radio Receiver and Transmit ter BC 800 A Check antenna cords and connections Replace Radio Receiver and Transmit ter BC 800 A Check all connections Turn the switch to Replace Radio Receiver and Transmit ter BC 800 A Replace Indicator 929
30. radio set are normally connected for 24 volts direct current and 400 2400 cps alternating current However operation at 80 volts alternating cur rent 400 2400 cps has been provided for See paragraph 4 Power for operation of the radio set is normally obtained from the power supply of the radio equipment with which it is associated as an auxiliary If the associ ated radio equipment is not installed in the particular airplane in which Radio Set SCR 729 A is used the 115 volt 400 2400 cps is obtained from an inverter The d c power used in the operation of Radio Set SCR 729 A is obtained from the airplane battery 2 PRINCIPAL COMPONENTS Principal components of Radio Set SCR 729 A or SCR 729 AZ with their weights and overall dimensions are listed in the table below Dimensions Quantity H eight Width Depth Weight Required Inches Inches Inches Pounds Radio Receiver and Transmitter BC 800 A or BC 800 AZ Indicator BC 929 A or BC 929 AZ Radio Set SCR 729 AZ requires 12 volts direct curren 1 21 83 16 26 0 RESTRICTED Quantity Required Unit Inches Inches Inches Pounds Height Widib Depth Weight Radio Control 1145 2 Antenna AN 148 A Receiving Antenna AN 147 A Transmitting ho 1 Mounting 406 1 Mounting FT 409 A 1 Mounting FT 416 A As RF Cable requi
31. red IRG 8 U 1 Plug AN3108 18 3P 1 Plug AN3108 22 17P i Plug AN3108 22 17S 2 Plug AN3108 168 45 2 Plug AN3108 18 3S hte AAA AA AN AAR NR e aaee eara rt Ud gari i 15 Plug PL 259 1 Visor for Indicator 4 RADIO RECEIVER AND TRANSMITTER BC 800 A 1 This unit is a complete radio receiver and trans mitter which will receive on two preset frequencies and transmit on one frequency The front panel contains seven female sockets for coaxial connectors two two prong male one two prong female and one nine prong female socket for power and control connections See figure 2 for socket markings bandi Section Paragraph 3 RECEIVER OSCILLATOR ADJUSTMENTS RECEIVER TUNING ADJUSTMENTS TRANSMITTER FREQUENCY ADJUSTMENT MOUNTING 416 Figure 2 Radio Receiver and Transmitter BC 800 A 2 Three receiver tuning adjustments are located in windows of the case of the receiver under which the panel markings RECEIVER TUNING 1 2 3 appear The oscillator of the receiver OSC is tuned by two slotted shafts marked HIGH LOW The trans mitter frequency adjustment is a single screw adjustment marked TRANS FREQ Hote Radio Receiver and Transmitter BC 800 A and BC 800 AZ will be modified on or about 15 May 1944 by addition of a tuning knob or a flexible tuning shaft
32. reen with the HOR CENT control as shown in figure 12 or 26 RADIO RECEIVER AND TRANSMITTER BC 800 A RADIO CONTROL BOX 1145 INDICATOR 936 RESTRICTED 08 405 729 2 1 Throw the toggle switch on Indicator 936 A to PULSE Press the PUSH button on Indi cator BC 936 A The transmitter pulse will now appear on the screen of Indicator BC 929 A as a rectangular pulse as in figure 16 or 30 With the RANGE switch of Indicator BC 929 A set at 10 the pulse should have a width of less than half of one vertical division as in figure 16 or 30 k Disconnect Indicator BC 936 A and nect the video cable to the video socket of Indicator BC 929 A Disconnect the other end of the video cable from the TRANS ANT socket of Radio Receiver and Trans mitter BC 800 A and reconnect to the video socket of the receiver and transmitter Reconnect TRANS ble to TRANS ANT socket The equipment should now check with the cording diagram figure 6 INDICATOR BC 929 A 30 100 VER CENT jo ya VIDEO OFF ey SYNC 50 on CENT o 1 10 50 100 INT RANGE FOCUS 24V D C 1 PLUG PL 259 Figure 25 Power Output Check Cording Diagram 14 RESTRICTED RESTRICTED Section AN 08 40SCR729 2 figure 28 Sweep Trace Statute Scale Set Figure 29 Power Output Signal Statute Scale
33. the VER CENT control may then be necessary to again align the 2 mile calibration point Adjust the sweep duration marked 10 so the lines stop when they reach the 10 mile horizontal line 1 Turn the range switches on Indicator 929 A and Range Calibrator BC 949 A to the 50 position and turn the screwdriver adjustment marked SWEEP AMPLITUDE until the 40 mile calibration point lies over the 40 mile horizontal line Repeat step k using SWEEP DURATION 50 control No adjustment of VER CENT should be made except on the 10 mile range m Place range switches on Indicator BC 929 A and Range Calibrator BC 949 A on the 100 mile range and turn the screwdriver adjustments marked SWEEP AMPLITUDE until the 80 mile calibration point lies 40 sha ON sans ala 1 Pe eed lina D annat otan 35d ULLI OVU horizontal 4111 M SWEEP DURATION 100 control Hote The sweep trace shifts slightly when a different RANGE scale is selected The VER CENT control should be adjusted for the range requir ing the most accuracy This will depend on the nature of the mission 12 RESTRICTED RESTRICTED AN 08 405CR729 2 Disconnect Range Calibrator BC 949 A and associated cables from Indicator BC 929 A and reconnect all cable plugs which were removed In reconnecting the equipment follow the cording diagra
34. ts for mechanical defects and loose fittings 5 Check the plugs and sockets for good electrical contacts Clean with carbon tetrachloride if necessary 2 ADJUSTMENT 4 PRELIMINARY OPERATION CHECK 1 Check the mountings of the various compo nents 2 5 4 Check the cords using the cording diagram figure 6 5 Turn the GAIN control on Radio Control Box 1145 and the INTENSITY control on Indi cator 929 to the maximum clockwise position mad OR Check the transformer connections Check the fuses during soldering operation Figure 9 Coaxial Cable Diagram a Remove 11 16 inch of the rubber insulation and braid shield from each end of the cable b Remove 14 inch more of the rubber insulation from each end of the cable c Remove V5 inch of the inner insulation from each end of the cable d Place Connector PL 259 or PL 259 A on eoch end of the cable e Refer to the above illustrations for soldering the braid shield and the inner conductor to the connector f Slip the threaded clamp of the connector into position CAUTION Do not overheat the insulation of the cable Eaa os a TENEO S Section Il RESTRICTED 08 40SCR729 2 TO 115 VOLT SUPPLY Me UA A C POWER CABLE E TO 24 VOLT SUPPLY AN 3108 165 45 D C POWER CABLE F
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