Specifications

TM 11-5820-670-30
2-31. CARRIER SQUELCH ADJUSTMENT. (CONT)
ADJUSTMENT PROCEDURE
1. On TS-2575/ARC-131, place the +28 VDC ON – OFF switch to ON.
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EL1AT239
Set carrier squelch potentiometer R5216 on A5500 assembly fully clockwise.
Set RT-823/ARC-131 SQ ADJ control fully clockwise.
Set control unit mode switch to T/R. VOL control fully clockwise, SQUELCH switch to DIS,
and frequency selectors to 60.05 MHz.
Set AN/URM-127 amplitude control to 0 and adjust output frequency to 1000 Hz.
Set AN/URM-103 FUNCTION selector switch to EXT MOD and adjust output for 10 microvolt.
Adjust AN/URM-127 for 8 kHz deviation as indicated on AN/URM-103 meter.
Set TS-723A/U function switch to METER and tune AN/URM-103 frequency to 60.05 MHz as
indicated by maximum indication on TS-723A/U meter.
Set control unit SQUELCH switch to CARR.
Reduce AN/URM-103 rf output to minimum, then slowly increase output to a point where
squelch just breaks.
If receiver-transmitter breaks squelch at an input of more than 0.7 microvolt, rotate
R5216 on A5500 assembly counterclockwise so that squelch breaks at 0.55 microvolt.
Remove AN/URM-103 input to receiver-transmitter, rotate SQ ADJ control fully counter-
clockwise, and ensure unit is unsquelched.
Rotate SQ ADJ control clockwise until receiver-transmitter just squelches.
2-135