Sealing coax doesn't have to be messy. I wrap with a silicone tape. Then I
wrap with black electrical tape. I finish it off with a couple of coats of
liquid tape. Even on the rainy side of the Big Island of Hawaii never a
problem. Plus, it's pretty easy to remove. Just cut with a utility knife and
peel back.
Bill K4XS/KH7XS
-----Original Message-----
From: George Harlem <george.harlem@gmail.com>
To: Franki ON5ZO <on5zo@telenet.be>
Cc: cq-contest <cq-contest@contesting.com>
Sent: Tue, Nov 1, 2016 2:30 pm
Subject: Re: [CQ-Contest] oxidized inner conductor when coax carries DC power
H2O molecules are pretty small. I'm told that copper oxide eventually turns
from green to black. I use Coax Seal, but it can be nasty to remove-- at least
it seems to do its intended job. George W1EBIFrom George's iPhone> On Oct 31,
2016, at 6:51 AM, Franki ON5ZO <on5zo@telenet.be> wrote:> > Probably not the
appropriate forum but there ought to be a technically skilled ham here? Sorry
that this post isn’t about cheating and what defines ‘assistance’. Some
contesters have real issues though.> > A few weeks ago I was doing some
relocating and rerouting of the coaxes outside. One RG-213 is used for my
active RX loop. It needed a different plug on the antenna switching side so I
cut the existing one off and prepared the cable for a new one. Much to my
surprise I found the inner conductor black from corrosion. I cut off a few
centimeters at a time, but after having cut off two meters, it still was black.
I have been working with these things for ages and I can tell you: it is NOT
water ingress. Everything is sealed properly. I was a pain to solder the new
plug to the center conductor. I had to sand the black film off and even then
the tin wouldn’t flow.> > Last week I took the loop down and cut away the
layers of tape that kept the feed point coax dry. And dry it was. However I
noticed the N male-female junction had a green mush developed around the mating
pins of the inner conductors.> > I didn’t pay attention in chemistry class, but
I’d label this as corrosion. Right?> Since I have never seen this before, and
this is the only coax that ever carried DC around here, I assume the DC voltage
is the culprit here?> > * Can I avoid this?> * Does it hurt? I seem to remember
something about DC and polarity that can eat your copper away?> * My coax
shields are tied to a dedicated earth system. Does this relate to the corrosion
in a good or bad way?> > I’m thinking of ways to improve my 80/160 RX
situation, and several scenarios involve DC over the coax. So I better know
what I’m up against.> Thanks and 73> Franki ON5ZO / OQ5M>
_______________________________________________> CQ-Contest mailing list>
CQ-Contest@contesting.com>
http://lists.contesting.com/mailman/listinfo/cq-contest_______________________________________________CQ-Contest
mailing
listCQ-Contest@contesting.comhttp://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|