Cavity & Duplexer Tuning Bandpass Adjustment; Passband Adjustment - Motorola R-2001D Operator's Manual

CAVITY
&
DUPLEXER TUNING
BANDPASS ADJUSTMENT
A. Passband Adjustment
I. Connect the Analyzer's RF InlOut to the in-service duplexer
~ntenna
port as shown in figure 4-21.
2. Set DISPLAY to GenlMon Mtr, FUNCTION switch to Generate FM, and MODULATION switch to off posi-
tion.
3. Enter the receiver frequency.
4. Set the RF Step attenuator to
-30
dB and the Variable control to mid-range, to allow adequate signal to get
through a mistuned duplexer and quiet the receiver. Reduce the signal generator output, as necessary, to keep the
receiver limiter meter reading below saturation.
5. Tuqe the pass-band knobs of the cavities in the duplexer receive leg, for a peak reading on the receiver limiter
meter. Reduce the signal generator output, as necessary,
to
keep the receiver limiter meter reading below satura-
tion. This completes the pass-band adjustment for the receiver leg.
6. Set the FUNCTION switch to Monitor FM and the attenuator to -30 dB. For low-power transmitters, it may be
necessary to reduce the attenuator setting to unsquelch the monitor. Too high an attenuator setting or too tight a
squelch setting will inhibit the display of frequency and deviation information.
7. Enter the transmitter frequency. Key the transmitter and tune the pass-band knobs of the cavities in the duplexer
transmit leg for maximum power output. This completes pass-band adjustments.
4-38
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