[TowerTalk] Question regarding electrical connectivity of frozen telescoping aluminum tubing

[Bob Shohet, KQ2M]

Hi Rick,

If you some have “grit” between the elements, (sand grains, spider/insect webs/debris, previous conductive paste in the element, etc.) you can have two telescoping tubing pieces that are mechanically stuck together, almost impossible to dis-assemble, and have either no connectivity or poor/intermittent connectivity.

Even if you have connectivity, I would still separate the pieces of tubing, clean thoroughly with steel wool and a scotchguard pad, wipe everything off and dry it, and then put a thin bead of Noalaox or Penetrox (I have used both) on a paper towel, and then put on a nitrile glove and, while grasping the element through the paper towel, close your had smear it onto the element, and then rub up and down the element and sideways in a twisting motion while you are still grasping the element so that you get the “goop” on all parts of the element.  Then put that into the thicker piece of tubing and slide it in and out several times about 1’ longer than the thinner tube needs to telescope out of it.  Now you will have a thin, well distributed layer of conductive paste on the thinner element and inside the thicker element with an excellent electrical and mechanical connection.  

You can be sure of the reasonably certain of the connectivity between the elements as well as the ability to separate them in the future.

73

Bob KQ2M


From: Richard (Rick) Karlquist 
Sent: Wednesday, July 17, 2019 6:20 PM
To: towertalk at contesting.com 
Subject: [TowerTalk] Question regarding electrical connectivity of frozen telescoping aluminum tubing

I bought a used KT34XA and between the seller and me I disassembled
it enough to get it home.  Another KT34XA owner recommended that
I disassemble it completely  and buff it with Scotch bright and
then reassemble using NoAlOx.   The purpose of this was to assure
good electrical conductivity.

This raises the question:  if an old antenna has difficult to
disassemble tubing pieces, is it possible for two pieces
to be mechanically stuck together yet have poor electrical
connectivity?  Or conversely, if conductivity looks good using
a 4 wire ohmmeter, are we in the "don't fix it if it ain't broke"
mode.

I've seen a lot of discussion about ways to unfreeze elements
but this topic doesn't seem to have been covered.

Rick N6RK
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