"David" wrote in
:

....
The only place I didn't put any grease was on the elements were the
matching network connects to. I used clear silicon sealant for those.

Was it a water based silcone sealant? I have observed high VSWR and noise
on an antenna feed that used such, until the stuff had thoroughly dried /
cured. It does not seem to be affected by rain since the initial cure.

If it was not a neutral cure silicone, perhaps there is something galvanic
going on?

Owen