Motorola MTR2000 T5544 Instruction / Field Service Manual page 320

VHF Duplexer Module
Duplexer Tuning Procedure
12
The duplexer field tuning procedures are provided in Figure 9. The proce-
dures are most easily performed with the duplexer module removed from
the station rack or cabinet. Be sure to make note of the transmit and receive
frequencies for the particular station before beginning.
If the duplexer module is tuned according to instructions and does not
meet specifications for return loss, insertion loss, and/or isolation, you
must return the duplexer for repair.
The notch (reject) frequency will maintain its spacing to the pass frequency
when the pass adjustment of a cavity is moved several MHz. For example,
a system operating at 135 and 138MHz, which is moved to 138 and
141MHz will require a minimum of readjustment if the pass adjustment is
made first. It is therefore recommended that the pass adjustments be
made first and that the procedure provided in Figure 9 be followed.
68P81085E16-B
09/30/05