Glenayre Document Number: 9110.00148
RL-903 Receiver
Issue 1, Rev. C: 12/10/96
MAINTENANCE
RF and IF Tuning Procedure
Note
Hint: You may prefer to use the RSSI output at RF board J1-12 (TB3-5),
rather than tuning for maximum sensitivity by ear.
1.
Attach RF signal generator to rear-panel antenna input J1. Set generator to receive
frequency. Modulate with 1000-Hz tone at +1- 3.0-kHz deviation (+/-1.5-kHz for
12.5-kHz-spaced channels). Set level to -47 dBm.
Note
This is the standard test signal standard test signal.
2.
Set front-panel SQUELCH switch to TEST.
3.
Adjust speaker audio level with VOLUME control to suit user preference.
Caution
The RF front-end adjustments should be tuned for
a relatively flat response characteristic, not for
peak response. Do not perform steps 4 through 8
unless this is an emergency repair. The factory
setup procedure requires a spectrum analyzer. Call
Glenayre for assistance in replacing the assembly
or in performing the alignment. Alignment should
not be necessary unless a major change in
frequency has taken place.
4.
Refer to Figure 7-4. Loosen lock nuts on RF assembly resonators L2, L3, L4, L7, L8,
and L9.
5.
Reduce signal generator input as required. Using hex wrench, adjust resonators in se-
quence for maximum sensitivity. Repeat this step until no further improvement is not-
ed.
6.
Adjust RF resonators L2, L3, L4, L7, L8, and L9 for signal peak. While holding reso-
nators firmly with hex wrench, tighten all lock nuts to prevent further resonator
movement. Constantly check that receiver sensitivity has not been degraded by inad-
vertent movement of resonators or stress to mechanical assemblies.
Caution
Do not overtighten lock nuts.
7.
Passband ripple tends to he additive when all adjustments are made to cause a peak
response at a single frequency. To ensure that passband ripple does not degrade per-
formance due to temperature drift, set synthesizer to 3 MHz above carrier frequency
and set signal generator accordingly. Response should be within 2.5 dB of perfor-
mance at carrier frequency.
Date: 12/05/96
Copyright ©1996 Glenayre
Page:
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