[TowerTalk] Water in my XM240

[kk9a@arrl.net]

I never use end caps on elements or the boom.  I just see them as a moisture
trap and I really haven't seen any problems with not using them.  I did have
a wasp nest in one of my lower antennas once, but that really never caused
any problem.

The usefulness of an aluminum to aluminum compound probably varies depending
on how corrosive of a location you are in.  I don't think northern Alabama
is that corrosive.  I have not used it on the majority of my antennas in
Illinois and I've never had problems disassembling the antennas or noticed
any corrosion problems.  In fact it was more difficult for me to disassemble
an antenna that I used Penetrox on because the compound hardened.  I also
purchased a used antenna that once belonged to AA6TT/0 and it was a little
bit of a job cleaning off the hardened compound before reassembling it.  The
compounds do however help keep a good electrical connection - especially in
a corrosive environment.  I use it on all of my antennas in Aruba.

73,
John KK9A / P40A




Subject: [TowerTalk] Water in my XM240
From: K4SAV

For the past eight weeks, my XM240 has been sitting in my back yard on
concrete blocks, awaiting the arrival of my 4 element SteppIR. Today I
removed a couple of the elements and found a lot of water inside. (Much
more than can be accounted for by condensation.) Then I noticed that
there are no weep holes on this antenna anywhere, and the element ends
have rubber caps. I inspected the elements for a possible hole to let
water enter. I found that the loading-hat-cross was mounted by two holes
drilled through the elements. That looked like the best spot for water
to enter. I packed duct seal around the screws.

There was also water in the element sections, closer to the boom. This
section was blocked from the end section by the solid fiberglass rod
that the loading coil was on. I don’t know how water got in this
section. Maybe it’s coming in around where the sections are telescoped
together and clamped with hose clamps, although the fit looks tight and
there are no obvious holes.

I am beginning to wish I had used Noalox on the areas where elements are
telescoped together and clamped. The manufacturer didn’t say to do this,
but it sounds like a good idea to me. Can any of you think of any reason
why this is not a good idea? What do other antenna manufacturers
recommend? It’s a lot easier to do this while the antenna is still
sitting on the ground.

It won’t bet the first time I have violated the prime directive with
this antenna, I used Noalox on the bolts when the manufacturer said to
use liquid soap. Soap just seemed too water soluble to me for this
application.

Jerry, K4SAV