Joe S. wrote:
(snip)
I have found a source of anti-oxidant grease that's used on electrical
connections and I will put this stuff on the connector-mount junction to
prevent further oxidation. Here's the question: Do I loosen the nut and
put grease between the nut and the antenna mount -- similar to putting
thermal grease between a heat sink and the surface of a transistor -- or, do
I tighten the nut and smear grease on the outside, not on the mating
surfaces? I suspect I should put the grease on the mating surfaces between
the nut and the mount -- loosen the nut, smear on grease, tighten the nut.

The anytioxidant has to be in intimate contact with the metal surfaces
before they are clamped together. Here is a site that tells how to
use one version, Penetrox-A. The details are about 1/4 of the way down:
http://www.inspect-ny.com/aluminum/alreduce.htm#1A