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Re: [TowerTalk] Lightning suppression through coax loops

To: <n4zr@contesting.com>, <TowerTalk@contesting.com>
Subject: Re: [TowerTalk] Lightning suppression through coax loops
From: "Wes Attaway \(N5WA\)" <wesattaway@bellsouth.net>
Date: Thu, 27 May 2010 08:57:32 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I believe I remember that the old Polyphaser manual had some info about coax
loops and bends.  The idea is simple, and makes sense, because the grounding
at the tower and at the entrance to your house, etc., is creating a
voltage/current divider that will, ideally, shunt most of the energy to
ground before it gets to your house.

The Polyphaser manual explained that loops and bends in coax runs toward the
point of entrance add inductance to that path and cause it to be
incrementally less attractive for the lightning energy.

I see no reason to doubt this because it is simply a practical application
of Ohm's Law.


------------------ Wes Attaway (N5WA) ------------------
1138 Waters Edge Circle - Shreveport, LA 71106
    318-797-4972 (office) - 318-393-3289 (cell)
        Computer Consulting and Forensics
-------------- EnCase Certified Examiner ---------------
 

-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Pete Smith
Sent: Thursday, May 27, 2010 7:10 AM
To: TowerTalk@contesting.com
Subject: [TowerTalk] Lightning suppression through coax loops



73, Pete N4ZR

The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
reversebeacon.blogspot.com
I bought an Ameritron RCS-10 antenna switch at Dayton, and in reading 
the manual (please, no giggling) I note that it calls for a two-turn 
loop in each antenna coax line just before entering the relay box. 
These are described as "drip and lightning retarding loops." The manual 
is quite prescriptive (for example, "keep coils spaced from each other 
by vertical or horizontal separation of 2" minimum"), and I get the 
"drip" part, but I wonder what the real, practical effect of these loops 
would be.  Is there enough inductance to offer any practical blocking 
effect for induced voltages resulting from a nearby strike?
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