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
