Funny you should run into this problem... another group member and I have been talking about pretty much this same strange problem in regards to his extra set of Wacom Duplexer Cavities.
He exhausted a number of serious RF test examples to his problematic Wacom duplexer as a package and as individual combinations of cavities and configurations. Different frequencies, hardware, coax harness, tuning, external/local connections, desense testing, physical cleaning, yadda, yadda, yadda and still the desense gremlin remained regardless of what he did/tried. I wouldn't speculate what the problem is/was unless I had the assembly here in front of me. At this time I/we could only present you with a list of suspected gremlin sources based on opinions, guesses, historical references and experience. I can tell you I have seen, heard about and run into a few antenna system hardware combinations that just don't work as advertised. Many of these head scratchers have been related to hardware in the application of antenna combiner and repeater duplexer. Apply the "no free lunch rule". cheers, skipp skipp025 at yahoo.com www.radiowrench.com > "blisswheeler" <[EMAIL PROTECTED]> wrote: > > I've run into a problem that baffles me. > > I have two sets of WACOM WP-641 4 can Duplexers. They have been tuned > to TX on 146.96 mHz and RX on 146.36. One set was tuned in a > Professional Lab, the other I tuned myself. They tune very well with > excellent rejection ~90db. When I duplex into a dummy load running > 100W, I can inject a signal with an iso-tee and there is vertually > zero desense to the receiver. When I hook it to an antenna it > instantly experiences 30db of receiver desense. I can lower the power > to 3 watts or less and still have 20db desense. I have a GE Mastr II > repeater, but I've used a separate Transmitter and receiver and > experience the same results. > > I'm using double shielded RG214 for testing. I've also used 1/2" > heliax for testing from the duplexer to the antenna. I've used 3 > different antennas. 2 different colinear and a j-pole. The antennas > all have less than a watt reflected out of 65W forward. I've used > separate antennas on the TX and RX Cans with the same results. When I > terminate either TX or RX into the dummy load the desense disappears. > It appears that when the reactive component is introduced everything > goes to pot. > > It doesn't make any sense to me. Any Ideas? I'm stumpted.. :-( > > Thanks, > Bliss >
