I just went through a similar nightmare with another repeater that was 1200 KHz above our repeater's input frequency. Turned out that the coax jumpers between each can in the duplexer array had deteriorated and needed to be replaced. I was dealing with an 8 can arrangement, so there were lots of jumpers to replace. Replacing those jumpers eliminated about 95 % of the problem and then the final culprit turned out to be a bad coax "Tee" connector that tied the receive and transmit sides of the duplexer to the antenna. I then replaced that "Tee" connector and the problem disappeared completely.
After this, I went back and retuned the duplexer and the results were amazing! Now the system is much more sensitive than it has been in many years, and most of the scratchy noise complaints on fairly strong signals have disappeared. pat scolla, wb0egr Harford County, MD RACES Officer Harford County, MD ARES EC
