Let me start by saying that I do this kind of thing all day long for a living. I have seen it occasionally on some commercial systems with the same antennas. I have all TX/RX 6 cavity duplexers, and the repeaters are Motorola (CDR or R1225 type) with circulators and line matchers if needed. I spent a few hours at the problem site the other night and no matter how I was trouble shooting it, it pointed to the antenna system (beyond my polyphaser lightning protection at the ground window/entry). This is definitely an external mix (IM) that includes my transmit signal. The mix is strong enough that I can see it on my service monitor inside the concrete building. No problems at all with a dummy load, and cutting my power output to exciter only reduces but does not eliminate the problem.
hope that all makes sense .. James Jay Urish wrote: > > It's not an antenna problem.. What duplexers are you using?? Repeaters? > > James Delancy wrote: > > > > > > Just a quick question for the group. I have two repeater sites with > > DB224-E antennas on them (ham/gov't split). One repeater site tends to > > feed back upon itself often (duplexers, radios, cabling inside all ok > > into dummy load, antenna SWR good). The other repeater site does this > > occasionally. Has anyone had any experience with this problem with > > these antennas ... and what is the fix (other than replacement). > > Station Masters do sound like a good but expensive option though. > > > > Thanks! > > > > James > > > > > > -- > Jay Urish W5GM ex. KB5VPS > > ARRL Life Member Denton County ARRL VEC > N5ERS VP/Trustee > > Monitoring 444.850 PL-88.5 146.92 PL-110.9 > >
