In article ,
says...

Hi, my old HT DMM is still abandoned, but...
I must repair a Vertex VRX-7000 repeater that has a noisy output:

https://i.postimg.cc/3JhhbHpC/IMG-3321-1.jpg

Do you know how can generate this noise, also UNDER the trasmitting
frequency?
The receiver frequency falls in the noisy area, and when I connect a
duplexer, the sensitivity of receiver is blanked.




Go here and ask the question , Many repeater owners are here.

https://groups.io/g/repeater-builder


It could normal for the transmiter. How many notch cavities are you
using for a duplexer