Instruction Manual

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3.8 TRANSMITTER SIDETONE LEVEL ADJUSTMENT
1. Set the transceiver operating frequency to 155.000 MHz and connect an appropriate test
receiver to the RF output connector. Ensure that the output of the transceiver is
terminated into a proper dummy load.
2. Key the transmitter and input a -10 dBm (0.25 VRMS), 1 KHz audio signal into the
microphone input.
3. Select the sidetone adjust command and then adjust the sidetone level using the guard
volume control to produce a +3.0 dBm (1.0 VRMS) 600 ohm audio output.
3.9 MAIN AND GUARD SQUELCH ADJUSTMENT
The squelch on both the main and guard receivers is factory set to open at approximately
0.5 microvolts. This adjustment can be made or altered to suit local conditions as follows:
1. Set the main receiver of the transceiver to 155.000 Mhz. Connect a signal generator to
the antenna input of the transceiver.
2. Set the signal generator to produce a ±3 KHz deviation with a 1 KHz tone on 156.000
MHz. Increase the signal generator RF level from 0.1 uV until the squelch indicator LED
is on. Verify the receiver SINAD ratio is between 12 and 14 dB.
3. If not, re-adjust main receiver squelch via the main receiver squelch software command.
4. Repeat the above procedure to adjust the guard receiver squelch setting using guard
receiver squelch adjustment software command.