At 2/23/2007 12:50 PM, you wrote: >With respect to using the GE MII mobile frame for repeater applications: > > > 1. Can you say categorically that there is sufficient TX/RX shielding > to prevent any desense at any power level the conversion is capable of > operating? > >In my experience, yes. In fact, we have had several repeaters that the >sensitivity actually gets BETTER with the transmitter active. (due to the >correct 50 impedance being applied to the TX port of the duplexer)
Hmmm, that sounds rather unusual. I can see the non-50 ohm impedance at the TX port pulling the notches on the RX side, but I wouldn't expect it to affect the much broader RX pass response to the point of degraded RX sensitivity. I have experienced this phenomenon before, but without a duplexer (or anything except a load for the TX) connected to the radio. In my case it was due to "leaking" the RX RF from the signal generator (in this case just an HT) through the radio's case & the RF taking different "paths" through the radio to the RX between the TX on & TX off conditions. Sometimes the RX would degrade with the TX on (as expected), & sometimes it would improve. Both conditions were eliminated when the sig. gen. was properly coupled to the RX's RF input. Bob NO6B
