Page 5-18
400 SERIES MAINTENANCE MANUAL
Rev. C
P/N 190-00140-05
5.7.2.8
Sidetone
1. Apply a standard mic input signal. Measure com audio out and while transmitting, verify
sidetone level is 1.4 Vrms
0.2 Vrms.
118.50 MHz ______ Vrms
127.50 MHz ______ Vrms
136.50 MHz ______ Vrms
5.7.2.9
MIC Intercom Test
1.
Remove RF input from the unit.
2.
Squelch the receive audio (enable compressor).
3.
Apply a 125 mVrms, 1 kHz audio signal to the intercom mic audio input.
Audio Level ________ > 7.07 Vrms
4.
Remove intercom audio input signal.
5.7.2.10 Receiver Sensitivity
1.
Disable the compressor.
2.
Apply a 2
P
V (hard), 30% modulated, 1000 Hz RF signal to the unit and set volume to rated
audio (
a
7.07 Vrms).
3.
Measure the sensitivity in the 25 kHz channel mode ( noise to noise ratio).
118.025 MHz ______ > 6 dB
127.000 MHz ______ > 6 dB
136.975 MHz ______ > 6 dB
4.
Measure in the 8.33 kHz channel mode.
118.030 MHz ______ > 6 dB
127.005 MHz ______ > 6 dB
136.980 MHz ______ > 6 dB
