[TowerTalk] Loss of wet RG-213

[Jim Thomson]

Date: Tue, 31 Mar 2015 14:40:09 +0000
From: Markku Oksanen <ww1c at outlook.com>
To: Keith Dutson <kdutson at sbcglobal.net>, "towertalk at contesting.com"
<towertalk at contesting.com>
Subject: Re: [TowerTalk] Loss of wet RG-213

Hi
Interestingly I can't find any figures for the loss!I can imagine that high F this may be really bad but how about 28 MHz?
Markku

## temp install a bird wattmeter at the top of the tower.  Then another in the shack.  Then apply exactly 1 kw..if using a 1 kw slug,
or 1.5 kw if using a 2.5 kw slug.   Then measure what you get at the top of the tower on the freq of interest.   Aside from the normal 
water proofing of your choice, you  should also use some form of a drip loop. 

##  back when I was 16,  I had a hb 20M GP  up 70 ft,  fed with  58-U..and NO connector at the base of the GP.   I used the ARRL
fubar method of hot side of coax to GP..and braid to the 6 x radials.  Then a bunch of tape and goop.  4 months later... I had water coming 
out of the coax connector in the shack !!    The water had migrated down the entire length of the braid !   Lesson learned.  The same silly fubar
method of connecting coax to a quarter wave sloper on a tower, is still depicted in the arrl ant book today...but even worse, with braid
attached to tower leg with a SS hose clamp !    A simple L shaped aluminum piece, aprx .25 inch thick, with the hole in it for a SO-239
on one side, and bolted to the trylon tower leg on the other side... is a better method.   Then water proof the connectors plus where the 
10 ga stranded RW-90 is soldered to the SO-239. 

##  Coax is expensive enough as is... esp the double braided RG-393 stuff.   Vapor wrap, plus T+B industrial heatshrink tubing... the
good stuff with the glue glop and ribs on the inside will water proof anything. Then wrap the heat shrink with 88 tape. 

Jim  VE7RF