[TowerTalk] Coax

[john at kk9a.com]

It would be interesting to see actual loss of Belden 8267 RG-213.  I only 
use it for jumpers and rotator loops and I use Heliax for long runs.

Johh KK9A




To:towertalk at contesting.com
Subject:Re: [TowerTalk] Coax
From:Jim Brown <jim at audiosystemsgroup.com>
Reply-to:jim at audiosystemsgroup.com
Date:Sun, 08 Apr 2012 21:11:58 -0700
List-post:<towertalk at contesting.com">mailto:towertalk at contesting.com>

On 4/8/2012 9:01 PM, Jim Thomson wrote:
> LMR-400db          .666 db
> LMR-400UF          .799 db
> RG-213U             1.024 db

RG213 is not a spec, it's a very broad generic description. There are
RG213s built with thin copper braid and others with heavy copper braid.
The loss in cable is a direct function of how much copper they use to
build it.  Based on resistance data, Davis's 213 is directly equivalent
to LMR400 for use on the HF bands.

##  say what.   Run 200 feet  of 213-U   into a dummy load at the far end, 
with
a wattmeter 1 foot before the dummy load.


You'll need far more precise instrumentation than a Bird to measure a
difference of 0.1 dB   Rather, you'll need a scope, RF voltmeter, or
spectrum analyzer that can resolve 0.01dB, you'll need to measure by
substitution, and you'd better make a bunch of measurements and compare
them.

73, Jim K9YC