"Owen Duffy" wrote in message
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"David" wrote in
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"Owen Duffy" wrote in message
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"David" wrote in
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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

It was normal sealant silicone from a diy store.

What is "normal".

There are two kinds commonly available, neutral cure and acetic acid
cure. Some of the neutral cure ones are water based (ie water washup of
un-cured material).

If you use acetic acid cured silicone on metals, it corrodes them.
Silicone sealants intended for roofing will have a neutral cure.

Do you know what you used?

Owen

Thanks for the explanation. I didn't know that the did a neutral (water
based silicone).

The one that I have used is the acetic acid cured silicone.