User's Manual

6. TRANSMITTER PERFORMANCE TESTS
Power Output
1. Set the power supply voltage to 13.8V dc. and monitor the voltage during transmit.
2. Switch data radio TX and check and record the output power. The nominal output
power is adjustable about 5W .
3. Set the PTT switch to OFF .
Peak Deviation
1. Connect the oscilloscope to the output of the modulation meter.
2. Set the AF signal generator to 1000 Hz at 106mV and connect to DATA _IN
Line ( pin 1 of J903 )
3. Switch data radio to TX and observe the oscilloscope display to check that the 1000Hz
tone is a sine wave and adjust RV501 to make deviation is about 3.5KHZ.
4. Using the AF signal generator, sweep from 100 Hz to 3 kHz and record the peak
deviation.
5. Check the peak deviation for appropriate channel spacing as follows：
For 12.5 kHz channel spacing, Peak deviation is not greater than 2.5 kHz.
For 20 kHz channel spacing, Peak deviation is not greater than 4 kHz.
For 25 kHz channel spacing, Peak deviation is not greater than 5 kHz.
Spectrum Test
It may be necessary to notch the fundamental signal during this test.
1. Connect a spectrum analyser and RF power meter to the antenna socket.
2. Switch data radio to TX. Observe the output spectrum on the spectrum analyser.
3. Adjust notch filter to minimise the carrier. All spurious and harmonics signals
should be below- 36 dBm up to 1 GHz and below –30 dBm between 1 and 4 GHz.
4. Switch off the data radio transmit control.
Receiver Performance Tests
Sensitivity
The SINAD performance test may be used to test the sensitivity of the receiver.
1. Connect the RF signal generator to the data radio BNC antenna connector.
2. Set the RF signal generator to the receive frequency .
3. Connect the leads of the SINAD meter between 0 V and pin 2 on J903.
4. Set the deviation to 60﹪ of the peak system deviation.
5. Set the AF generator to 1 kHz.
6. Adjust the RF signal generator level until the SINAD Meter reads 12 dB.
7. Check that the signal generator RF level is less than 0.35uV pd (-116dBm ).
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