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11. Adjust the RF output voltage level of the RF signal generator keeping the SINAD meter readings
between 6dB and 12dB .
12. Check for an RF voltage signal level of 0.31uV and a SINAD meter reading of 12dB or greater.
13. Select the highest receive frequency and check for a SINAD meter reading of 12dB or greater, at
0.42uV . (Sensitivity at the operational band edge).
14. Select the lowest receive frequency and check for a SINAD meter reading of 12dB or greater, at
0.42uV.
Discriminator Tuning
1. Set the RF level to 1.0mV .
2. Adjust T103 for a maximum audio output and on the oscilloscope monitor the sinewave distortion.
Adjust T101 and T102 for lowest distortion as observed on a distortion analyzer. This is normally
less than 3%.
Squelch Adjustment
1. Select a receiver channel that is programmed for narrow band (12.5 kHz) operation.
2. Set the RF signal generator to the receiver frequency. Set the AF modulation signal to 1 kHz at
1.5k deviation.
3. Adjust the RF output level of the RF signal generator until the 1 kHz signal is heard.
4. Adjust the RF signal to the level desired for squelch sensitivity as you monitor SINAD. This is
usually 8dB to 12dB SINAD.
5. On the main board adjust RV103 until the squelch is just unmuted (open)
6. Switch off the RF generator (squelch should close).
7. Switch on the RF generator. Squelch should open at the SINAD point where RV103 was adjusted.
This completes the narrow band adjustment.
8. Select a receiver channel that is programmed for wide band operation (25 kHz).
9. Set the RF signal generator to the receiver frequency. Set the AF modulation signal to 1 kHz at 3k
deviation.
10. Adjust the RF output level of the RF signal generator until the 1 kHz signal is heard.
11. Adjust the RF signal to the level desired for squelch sensitivity as you monitor SINAD. This is
usually 8dB to 12dB SINAD.
12. On the main board adjust RV102 until the squelch is just unmuted (open).
13. Switch off the RF generator (squelch should close).
14. Switch on the RF generator. Squelch should open at the SINAD point where RV102 was
adjusted.
15. Disconnect the test equipment.
MAXON SM-2000 MOBILE
SM-2450/UHF ALIGNMENT PROCEDURE
Page-28-
December 98