On Mon, Oct 10, 2022 at 04:09 PM, Stephan HB9EAJ wrote:
It's the speech compressor. It's not the problem, but it "amplifies" the problem.
Exactly. With the antenna connected directly to the radio and no counterpoise, some RF is finding its way onto the mic audio and the resulting noise is being boosted by the CMR compression. Adding a counterpoise or CNC ( or both ) will help but you can still have issues due to the radiating element being so close to the mic cable. I've done a bit of experimenting with this in the past as I had similar issues on a SOTA summit using exactly the same setup... I couldn't change my antenna setup at the time but found that turning off the CMR compressor stopped the symptoms on 15m and 10m. The proper cure would be to address the antenna issues.
