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Subject: Re: [TowerTalk] BLACKENED BRAID?
Date: Tue, 14 Jun 2011 11:55:16 EDT
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Here's what it says in the Coax chapter (page  140) in my UP THE TOWER book 
(_www.championradio.com_ ( ).
>  Another advantage of RG-213/U is that the jacket is made
from  non-contaminating PVC unlike regular RG-8/U. Any cable used
outdoors is  subject to years of sunlight abuse. The UV radiation
from sunlight causes a  chemical reaction with the standard PVC jacket
material and the chloride from  the jacket material (polyvinyl chloride,
remember?) starts to migrate, or  leach, toward the inner dielectric
and through the copper braid. Not only  does the braid get all gummed
up, but also it degrades the performance of the  coax and it only gets
worse over time. In an extreme case, the chloride will  coat each
strand of braid and actually insulate each strand from the  others.
You’ll have continuity on each strand but not from one to the  other.
The SWR of the coax (not the antenna) will rise over time due to  this
feedline degradation and you’ll have to replace it. If you are in  the
Sunbelt or are at a higher than average elevation, the  non-contaminating
jacket is probably mandatory.
    So your problem is either this or water incursion. 
Steve     K7LXC
Champion Radio Products
Cell 206-890-4188

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