Squelch sensitivity - SB-740-91-010234

SB 740-91-01

StepSetting and InstructionsNormal Indication

1Frequency accuracy

With an RT unit in transmit, see if reciver will

pick up the RT unit's transmission. Frequencies

used should be 30.05, 52.05, and 75.95 MHz. Ver-

ify tone quality and function of volume control

during this test. Volume control should be checked

for noisiness and flat or "dead" spots.

2Squelch sensitivity

(a) Noise (Old) operated squelch.

(1) Connect the equipment in accordance

(2) On AN/USM-207, set the controls as follows:

(a) Display Control . Set for desired dis-

play time.

(b) Sensitivity. 100 V

(d) Function. Freq

(3) On AN/URM-103, set the controls as follows:

(a) Band Switch.C

(b) RF Tuning: 41.05 MHz

(d) Function. 1000 Hz

(e) Deviation Adjust. For 8 kHz on Devia-

tion Meter.

(f) LO RF Set to Line. Right-hand meter

to red line

(g) RF Output. LO

(4) On Receiver R-442, set controls as follows:

(a) Band. A

(b) Light.On

(c ) MC TUNE KC. 41.05 MHz

(d) Squelch. Old on

(e) Volume. Fully counterclockwise

(f) Power. On reset

(5) Press Reset Switch on AN/USM-207

(6) Adjust AN/URM-103 RF tuning control for

41.05 MHz indication on the AN/USM-207.

(7) Adjust AN/URM-103 RF LO uV control for

minimum output.

(8) Slowly advance AN/URM-103 LO RF PV con-RF Attenuator micro-

trol until Call indicator lights. Notevolts control setting

setting of control.should be 0.7 iV or

less.

B-46