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[TowerTalk] Another coax question

To: towertalk@contesting.com
Subject: [TowerTalk] Another coax question
From: "Dan Zimmerman N3OX" <n3ox@n3ox.net>
Date: Sun, 5 Aug 2007 12:44:56 -0400
List-post: <mailto:towertalk@contesting.com>
Thanks for all the good info on RG-6 in ham applications.  It seems
like simple good sense to start using it so I'm going to get the tools
to do so.

I solved my UHF problem another way, though, and I wonder how
temporary I should allow the situation to be.

It turned out had about 30 feet of small Heliax that I saved from a
dumpster and then forgot about and I was able to solder crimp-type N
connectors onto that for the run to the roof.  For the flexible run to
the antenna around the rotor I used some RG-115 I had... which has
teflon(?) spiral wrapped dielectric, silver plated copper center and
shield and teflon spiral wrap covered in some fabric for the outer
jacket.  Overall the run loss is the same as if I'd used RG-6 the
whole way... the RG-115 may be lossier than I thought it would be at
UHF, but overall the system of feed and antenna is much better than
what I had before.

My question is, is RG-115 even quasi-weatherproof?   Water seems to
wick right into the fabric.. is it guaranteed to go through the teflon
wrap as well and just soak the whole cable the first time it rains?

I can't trust my loss measurements too much (cheap Rad. Shack
wattmeter), but it does seem like the loss splits up to about half a
dB in the 30 feet of Heliax and 1dB in twelve feet of RG115, so it
might be worth replacing the RG115 with something else, but if it will
survive the weather for a while, I'm just going to stay off the roof
in 90 degree heat.

So anyone know if RG-115 is indoor high-power cable only or if the
outer wrap of teflon actually manages to make the cable waterproof?

73,
Dan
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