You might try placing a relatively high value (10dB) attenuator in series with the receiver and note any difference in the problem. You can also try a high powered attenuator in various locations (tx/rx and duplex paths) to note differences.
Some informal relative thoughts... If the grunge/noise changes about 10dB you might figure the problem to be half duplex in that direction. If it changes 20dB the issue might be bi-directional at that location. Sometimes it might even go away when you modify the gremlin source path enough... Pads are a relatively easy and cheap test device, which sometimes with a bit of thinking can point you in a direction. Are you using a circulator/isolator? ... preamplifier? How much tx power? Does the problem happen at reduced power? Does red wine go with fish? cheers, s. > "jminn699" <[EMAIL PROTECTED]> wrote: > -I am having the same problem also with a wacom duplexer. On a dummy > load the tunning checks great with no desense, but with the antenna > attached the repeater will hang on transmitting noise as long as the > ttansmitter is on. > I can`t take the system off the air, and I don`t have another > duplexer. My short term solution has been to set the repeater hang > time to zero. Another would be to make the tx pl different from the > rx; but I am hoping to avoid reprogramming all the radios on the > system. > > My system is located in a lousy enviorment, a elevator equipment > room-there is a layer of carbon dust on everything. I suspect that > this dust may have found its way inside the cans, but I can`t take it > off the air to open up the cans. > > I hope someone has a solution to this problem. > > Joe > > > > > > -- In Repeater-Builder@yahoogroups.com, "Dan Cation" <dan-cat@> > wrote: > > > > Hi everyone - new to the group looking for help on a strange > problem. > > I've been involved with two repeaters in Southeast Kansas > (Humboldt - > > 147.18 and 442.900) for over 30 years and work in Electronics, > > although not in radio. A couple months ago we lost both repeaters > > when we had a flood in this area - I took the Wacom duplexer apart > and > > cleaned any obvious corrosion or such and assumed it would be fine - > > it tuned up without any trouble and there was almost no corrosion. > I > > replaced as many of the T connectors as I could and carefully > cleaned > > any that remained and made new cables of the correct length. I have > > built a new repeater but am now having a problem with intermittent > > buzzing sometimes when the transmitter is up - it will hold the > > receiver open and cover any signals that aren't pretty strong. > Comes > > on whenever the transmitter comes up but not always - sometimes it > is > > fine. I have tried 3 different transmitters - a Midland 3400, a > > Midland 340A and even a couple Icom rigs - makes no difference. > Same > > for receivers - makes no difference. Never shows up unless the > > duplexer is hooked to an antenna - works fine on a dummy load. > Tried > > two different antennas as well. The noise sounds like bad line > noise, > > but I can't hear it except on the repeater. The repeater is at my > > house right now, but I intend to haul it back to the site to see if > it > > shows up there as well when I can get time to do it. Anyone else > ever > > ran into this kind of thing? > > >
