AN/ARC-5 Handbook

							*** 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)