Adjustment Of Reject Notch On Transmit Leg - Motorola R-2001D Operator's Manual

CAVITY
&
DUPLEXER TUNING
BANDPASS WITH REJECT NOTCH
C. Adjustment of Reject Notch on Transmit Leg
1. Connect the Analyzer's RF In/Out to the in-service duplexer as shown in figure 4-23. Disconnect the cable at the
duplexer transmitter port that comes from the transmitter. Move the Analyzer's RF In/Out cable from the du-
plexer receiver port to the duplexer transmission port. Reconnect the cable coming from the receiver to the du-
plexer receiver port. Disable the receiver PL.
2. Set DISPLAY to Gen/Mon Mtr, FUNCTION switch to Generate FM. and enter the receiver frequency.
3. Set the attenuator to -30 dB and the Variable control to mid-range, to allow adequate signal to get through the
duplexer and quiet the receiver. Reduce the signal generator output, as necessary, to keep the receiver limiter
meter below saturation.
4. Adjust the reject notch adjustments on the duplexer transmit leg cavities for minimum signal level on the receiver
limiter meter. Change the signal generator output, as necessary, to keep the received signal up out of the noise and
below saturation.
5. Loosen the cavity reject adjustment nut and slide it within its slot while watching the meter. Tighten the adjust-
ment nut. Be careful not to mistune the rejection adjustment. Fine-tune the reject notch adjustment by turning the
bandpass knob a maximum of +/-15°.
6. Remove the test equipment and connect the duplexer back to the repeater. Check the duplexer for insertion loss
according to its specifications.
4-42