Belden 9913 is the most problematic coax that I have ever used. I think
that I do a pretty decent job of waterproofing connectors, but water
ingress was difficult to stop with the air dielectric. I have had no
problems with Belen 8267. I imagine that water also finds its way into my
underground conduits but I am not overly concerned. The wires inside are
for 24v rotators and 12v relays. I glued each of the 4" PVC pieces
together with no drains and have vented Hoffman boxes on the ends. My
feedlines are all direct buried next to the conduit.
John KK9A
To: TexasRF@aol.com
Subject:Re: [TowerTalk] water in EMT conduit
From: Grant Saviers <grants2@pacbell.net>
Date: Wed, 27 Feb 2013 15:34:23 -0800
"Hermetic" is very difficult to do. Belden withdrew their air dielectric
RG8 series coax because of water migration (original 9913 not current
9913F7). I know, I had 270' of it in a conduit. Consider also the perm
ratings of the plastic covering, water vapor can migrate through some of
them. I bought some 9913F7 when Buryflex was out of stock and regret it.
Direct burial rated coax and cables are best for any buried conduit.
I've also built some deflagration test chambers and stranded wire can't
be used in any seals as the leakage in between the strands is too much.
Grant KZ1W
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|