Horrible Interference on repeater

[N4DES]

No sir. Nothing has changed. I'm all but certain its propagation. I was just up at the site and there was zero interference today.
I saw where the station I believe is causing it modified their license about 3 months ago, and that's when it started. I've been trying to dig in a little, but the FCC site is extremely slow if it works at all seems like.

If you truly think that you found the offending user and it started about the time that they modified their license, reach out to the coordinator that did their license modification and advise them of the interference issue. If you do get through the FCC drama and find someone who is willing to work with you, the FCC will also engage the coordinator and if they made a mistake will want them to "work it out".

I had something similar with my HOA's Part 90 UHF repeater that I licensed and installed for them. It would get debilitating interference on the input frequency, a lot like yours, from a golf course irrigation system that was operating more than 4 times their licensed TX power output, no CWID, and antenna height higher than licensed. This is on the low power/low altitude part of the UHF spectrum, so the golf course's installation was totally illegal, but I brought them into compliance through the use of the coordinator.

 

[speedway_navigator]

In my early days of installing I put a base in the golf maintenance shop for the Lawrence Welk course in north county San Diego. A few weeks later I was in there for another task when one of the guys said every time they keyed it set off a sprinkler somewhere. I had not notice the sprinkler control was near where I ran the RG-8 (long before LMR400) and offered to move the install.

"oh no, we love to watch those old geezers run off the greens" was his reply.
Now I am one.