Hi Jeff, If you've got the patience... drop the transmitter down to the exciter only power and see if you can reproduce the problem at any time.
Do you have a circulator on the power amplifier's output? your turn cheers, skipp > "Jeff Lehmann" <[EMAIL PROTECTED]> wrote: > > I've been pulling my hair out trying to figure out a problem with my > 224.060 repeater in Norwell, MA. Somehow the transmitter is feeding > back into the receiver. This all started happening back during the > winter when a tower crew started working on the tower. Whether that is > a coincidence or not, I have no idea. > > My original antenna was at 120 feet (Hustler G7-220). After the tower > work was complete, I was able to get a Comet CA-Super22 installed at > the top of the tower (180 feet). Sometime during all of this work, the > feedback began to happen, while I was still transmitting and receiving > on the original antenna. The duplexer is a Wacom 6 cavity, transmitter > is a Hi Pro, and receiver is a Hamtronics. I also have a Kendecom 75 > watt amplifier, and the noise has been present with and without that > in line. > > Without the repeater transmitting, everything is fine, the receiver > has no noise at all, which I can listen to via the 6 meter repeater > that is on the same RC-210 controller. My latest theory was that it > happens more when there is slight tropo enhancement on the band, > usually in the evenings or early mornings, but I haven't proven this > yet. The duplexer has been tuned probably 3 or 4 times at this point, > by about as many different people, and it looks fine. I'd have no > problem buying a new duplexer if I could find that somehow, it was the > problem, even though it looks fine on test equipment. > > The latest things I tried was a DCI filter, which had the repeater > working great for about 10 minutes, then the noise came roaring back > in again. I don't know what else to try at this point. One idea that I > have is to try someone else's complete repeater system up there for a > couple days, so it doesn't involve tuning anyone else's duplexer. If > that repeater, on a different frequency still had a problem, then I > would know that it was something with the site/antenna system. If it > worked fine, I'd then know that it's something either wrong with my > transmitter/receiver or duplexer. > > I've tried different combinations of the 2 antennas, receiving on one, > TXing on the other, with some success at times, but the noise always > comes back eventually. If anyone has any suggestions, it would be > greatly appreciated. I just want to solve this once and for all. I've > got a great site, and want to use it to it's full potential. > > 73 > Jeff Lehmann - N1ZZN > Hanson, MA >
