Re: VHF antenna issues?
I had the same issue on my setup. It turned out to be an issue with the length of cable between radio and mast base. In the end I replaced it with new cable, and new soldered gold-plated plugs. That did the trick.
In my case I believe the issue was age-deteriorated cable and connectors. In your case it is all new, but termination is still a process that is susceptible to human error.
I think I would proceed by measuring the SWR of the antenna and cabling. If your radio is old and you don't mind getting a new one, I would try that. Thirdly, in my case, I found it helpful to buy and try one of those Shakespeare emergency antennas (which told me that the radio was fine). I kept it as a spare just in case.
1984 Bristol 31.1
Alameda, California, USA