AN/ARC-5 Handbook
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*** at 50,000 microvolts input 2--17. AVC CHARACTERISTICS. 2--18. LIMITS: 10X Normal sensitivity -- 50 to 150 mw. 100X Normal sensitivity -- 100 to 200 mw. 1000X Normal sensitivity -- 200 mw. 10000X Normal sensitivity -- 200 to 400 mw. Note Normal sensitivity is that setting of the signal generator output necessary to produce 10 mw receiver output. 2--19. PRELIMINARY INSTRUCTIONS. Obtain normal sensitivity before starting this check. This check may be omitted on R-23 and R-24 navigation receivers. 2--20. TEST PROCEDURE. STEP SIGNAL GENERATOR CONNECTIONS OUTPUT INDIC. & CONNECTIONS NORMAL INDIC. POSSIBLE CAUSES OF ABNORMAL INDICATION 1 Same as Steps 1 and 2 of SENSITIVITY check. 1. Audio amplification is insufficient. Refer to TROUBLE ISOLATION, Section IV, paragraph 4--4. 2 Increase attenuator setting 1000X the setting at normal sensitivity. Record reading of output meter. 200 mw indicates that the audio level is sufficient for normal operation. 2. Faulty AVC indicated by a decreasing output with increased signal input. 3 Increase attenuator setting 10000X the setting at normal sensitivity. Same as Step 1. 200 to 400 mw Refer to TROUBLE ISOLATION, Section IV, paragraph 4--7. 4 Set attenuator to 100X the setting at normal sensitivity. Same as Step 1. 100 to 200 mw 5 Set attenuator to 10X the setting at normal sensitivity. Same as Step 1. 50 to 150 mw
2--21. TRANSMITTER CHECKS. 2--22. POWER SUPPLY. 2--23. LIMITS: Input voltage 27.5 v dc. Secondary voltage 545 v dc. 2--24. PRELIMINARY INSTRUCTIONS: Use Test Set, AN/GRM-1, as shown in figure 1--3. Apply d-c power and allow time for the equipment to warm up. Depress the test key when recording all tests. 2--25. TEST PROCEDURE. STEP C-29/ARC-5 CONTROL BOX OPERATION TS- 58/GRM-1 READS VOLTMETER VALUES POSSIBLE CAUSES OF ABNORMAL IND. 1 Select transmitter 1 or 2 corresponding to the rack position of unit. Switch to CW and key transmitter. Dynamotor runs. Note any evidence of overload in the form of excessive noise or heat. Refer to TROUBLE ISOLATION, Section IV, paragraph 4--12. 2 Same. Switch TS- 58 to Position 1; read heater voltage. 54 divisions. 27.5 v 3 Same. Switch TS- 58 to Position 3; read B+. 51-55 divisions. 510-550 v 4 Switch to VOICE or TONE. Key transmitter. Same. 51-55 divisions. 510-550 v
2--26. TRANSMITTER TRACKING AND LOADING. 2--27. LIMIT: Phantom Antenna Plate Current: TS-58/GRM-1, pos. 5 Current No load (zero coupling) 10 25 ma Loaded-MCW-VOICE 20-40 50-100 ma Loaded-CW 60-80 150-200 ma Frequency Calibration: Within 0.03% of dial reading at any frequency, except at crystal frequency, where tolerance b 0.05%. **** R-F Power Output:CW emission--2.25 amps minimum (25 watts) VOICE emission--l.61 amps minimum (13 watts) unmod. TONE emission--1.85 amps minimum (17 watts) **** Above -- listed values of current measured on the ARC No. 7777 Phantom Antenna R-F current meter.
2--28. TEST PROCEDURE. STEP TRANSMITTER CONTROLS OPERATION NORMAL INDICATION ABNORMAL INDICATION 1 Select and switch on transmitter 1 or 2 depending on position in rack. Switch to CW. Unlock all transmitter controls. Set COUPLING and ANT. INDUCTANCE at zero. Set TS-58/GRM- I switch to position 5. Set transmitter dial to the lowest frequency. Observe TS-58 GRM-1 meter while tuning transmitter dial throughout its range. TS-58/GRM-1 meter reading should not exceed 10 through out the range of the tranmitter FREQUENCY dial. Refer to TRANSMITTER ALIGNMENT, Section III, paragraph 3t6. Refer to TROUBLE ISOLATION, Section IV, paragraph 4---16. 2 Set FREQUENCY dial, 100 kc from high end. 3 Set COUPLING at 3, and key the transmitter. Vary ANT INDUCTANCE from 0 upward, until antenna current is indicated. Adjust COUPLING and ANT INDUCTANCE carefully for maximum antenna current. Antenna meter reads 2.0 to 3.0 amps. TS- 58/GRM-1, position 5, reads 60.80 (150-200 ma). Refer to TROUBLE ISOLATION, Section IV, paragraphs 4--15 and 4--16. 4 Switch to VOICE. Key transmitter, Reduce COUPLING to zero; then advance clockwise until antenna meter reads 1.6 amps. Antenna meter reads 1.6 amps. TS-58/GRM-1, position 5, reads 20-40 (50-100 ma). Refer to TROUBLE ISOLATION, Section IV, paragraphs 4--16 and 4--17. 5 Same. Key transmitter, Loosely couple LM frequency meter to transmitter and adjust it for zero- beat with transmitter frequency. Frequency as indicated by the LM should be within .03 per cent of the frequency indicated on transmitter dial. Refer to TRANSMITTER ALIGNMENT, Section III, paragraph 3----6. 6 Repeat Steps 3, 4, and 5 with transmitter dial set at 100 kc from low end of band. 7 Repeat Steps 3, 4, and 5 with transmitter dial set to the crystal frequency. 8 Repeat Steps 3, 4, and 5 with transmitter dial set to the operating trequency.
9 Lock all controls except coupling control. 2--29. MODULATION CHECK. 2--30. PRELIMINARY INSTRUCTIONS: Modulation capabilities of the transmitter are determined by use of the oscilloscope, displaying a modulation envelope type of pattern. In addition to the normal oscilloscope control settings, the following should be observed: Oscilloscope Settings--Vertical input to plates direct. Sync control to EXTERNAL. Oscilloscope Connections-Sync voltage is obtained from one of the phone jacks in receiver rack or junction box. The vertical input terminal of the oscilloscope is loosely coupled to the transmitter R-F output, by attaching a wire, having good R-F insulation, to the vertical input terminal. The other end of this wire is brought close to the phantom antenna lead from the transmitter. The degree of coupling between these two leads will determine the vertical height of the modulation pattern. STEP TRANSMITTER CONTROLS OPERATION NORMAL INDICATION ABNORMAL INDICATION 1 Set emission to TONE. Key transmitter. Adjust COUPLING control for maximum Antenna current. Adjust sweep frequency controls of scope until two or more audio cycles are displayed. Adjust Sync control for steady pattern. Sinewave envelope pattern with no appreciable distortion; see figure 2--1. Modulation percentage should be 60 per cent or better as calculated by use of formula below. Refer to TROUBLE ISOLATION, Section IV, paragraph 4--17. 2 Set emission to VOICE. Key transmitter. Speak in mike at normal voice level. Observe that the modulation peaks rise to a higher value than that obtained for normal indication in Step 1. Refer to TROUBLE ISOLATION, Section IV, paragraph 4--17. MODULATION FORMULA: (A-B)/(A+B) * 100 = % modulation
SUMMARY TEST DATA CHECK OFF SHEET AN/ARC-5 Antenna Relay__________Mike Jack___________Phone Jack___________Dynamotor Ripple ___________ Calibration (.08%)__________Vibration____________Align Input__________Dyn. Overhaul Date_________ Max. Band Noise .19-.55mc .52-1.5mc 1.5-3.0mc 3.0-6.0mc 6.0-9.1mc (15 mw) ________ ________ ________ ________ _________SENSITIVITY HIGH END LOW END AVC CHARACTERISTICS (7uv) CW MCW INPUT OUTPUT RATIO LIMITS .19-.55mc _________________ _________________ NOR. SENS. ________ uv. (mw) .52-1.5mc _________________ _________________ 5X ________ 50-1001.5-3.0mc _________________ _________________ 10X ________ 50-150 3.0-6.0mc _________________ _________________ 100X ________ 100-200 6.0-9.1mc _________________ _________________ 1000X ________ 100-300 10000X ________ 200-400 AUDIO OUTPUT CW ________ MCW ________ 200 200 SELECTIVITY RECEIVER .19-.55mc .52-1.5mc 1.5-3.0mc 3.0-6.0mc 6.0-9.1mc LIMITS 2X ________ ________ ________ ________ _________ 2X -- 2.1-10 kc 10X ________ ________ ________ ________ _________ 10X -- 5-10 kc 10000X ________ ________ _________ ________ _________ 10000X -- 18 kc TRANSMITTER POWER TRANSMITTER TRANSMITTER TRANSMITTER OUTPUT FREQUENCY MODULATION TUNE-UP CW __________ 26 to 40 CW _________ VOICE _________ VOICE _________ .05% Approx. 70% Max. ant. current TONE __________ 13 to 26 VOICE __________ CHANNEL SEL. POWER SUPPLY 13 to 26 1 ______ 2 ______ IN _______ OUT ______ 27.5Vdc 545Vdc
SECTION III ALIGNMENT PROCEDURE 3--1. RECEIVER ALIGNMENT. Figure 3-1. Receiver Alignment Connections Figure 3-2. Location of Trimmers, Typical Receiver
3--2. PRELIMINARY INSTRUCTIONS.Output Meter--Daven, Model OP-182, connected into headset jack on receiver rack; IMPEDANCE SELECTOR set at 300 ohms. Signal Generator--LP-5 or Hickok 19X connected between the point indicated on alignment chart and ground. Controls-Set gain control at maximum, emission to MCW, signal generator switch ON, and dial as indicated in chart. Output Level--During alignment, the signal generator output must be attenuated to maintain the receiver output at 10 mw as indicated by output meter.3--3. RECEIVER ALIGNMENT NOTES.3--4. The receivers R-23, R-24 and R-23A normally operate with over-coupled I.F stages. For alignment, each I-F stage must be loosely coupled by pulling out the bakelite rod to the snap-out position. After the entire alignment is completed, the I-F stage must be returned to the same over-coupled condition. For the R-23 and R-24, over-couple the first I-F stage; for the R-23A and R-148, over-couple all I-F stages. 3--5. RECEIVER ALIGNMENT PROCEDURE. (See figures 3--1 and 3--2.) Before beginning alignment, check the positions of C4F and C4G and adjust them if necessary to the position shown in the table which follows. The positions shown are as seen from the FRONT of the receiver. RECEIVER C4F C4G R-23 R-24 R-25 R-26 R-27 Front of Receiver SIGNAL GENERATOR RECEIVER STEP CONNECTIONS TO RECEIVER FREQUENCY SETTINGS TYPE DIAL SETTING SPECIAL INSTRUCTIONS TRIMMERS 1 Through .006 mfd capacitor to mixer grid use MOD RF. 85 kc 239 kc 705 kc 1415 kc 2830 kc R-23 R-24 R-25 R-26 R-27 ANY DIAL SETTING See Receiver Alignment Note, paragraph 3--3. Adjust all I-F trimmers as indicated at right, for maximum output meter reading. C-21 C-38 C-37 C-18 C-36 C-13 2 Same Use PURE RF. Same Switch receiver to CW and adjust BFO trimmer for zero- beat. C-28
3 Same Use MOD RF. .52 mc 1.4 mc 2.9 mc 5.8 mc 8.9 mc R-23 R-24 R-25 R-26 R-27 .52 mc 1.4 mc 2.9 mc 5.8 mc 8.9 mc Switch to MCW. Adjust oscillator trimmer for maximum output meter reading. C-4E 4 Through .006 mfd capacitor to ANT post. Same Same Adjust R-F trimmer and ALIGN INPUT trimmer for maximum output. C-4D C-2 5 Same Same Same Adjust oscillator trimmer for maximum output. C-4E 6 Same .21 mc .57 mc 1.55 mc 3.1 mc 6.1 mc R-23 R-24 R-25 R-26 R-27 .21 mc .57 mc 1.55 mc 3.1 mc 6.1 mc Adjust oscillator padder, while carefully rocking the receiver dial, for maximum output. C-9 7 Repeat Steps 5 and 6 two or more times until there is no further increase in output when Step 5 is performed. Then, proceed with Step 8. 8 Same Use PURE RF. Same as Step 5 Same as Step 5 Switch to CW. Adjust oscillator trimmer for zero- beat. C-4E 9 Return I-F transformers to overcoupled condition: See Receiver Alignment Note, paragraph 3--3.
Figure 3-3. Transmitter Alignment Connections) Figure 3-4. Transmitter Adjustment Points (Top) Figure 3-5. Transmitter Adjustment Points (Bottom)