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[Towertalk] Proper way to ground open-wire feeders

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Subject: [Towertalk] Proper way to ground open-wire feeders
From: (Jeffrey Clarke)
Date: Mon, 26 Aug 2002 16:31:12 -0700 (PDT)
 I saw this post when reading the archives.....

 About 6-7 years ago - when I lived in OH -I had my center-fed 80 meter
zepp @ 30 ft hit by lightning. The 450 ohm feed was disconnected from
the tuner but was hanging inside the window of my shack.

The lightning blew a hole in the side of the shelf on my operating desk
and found a path to all my equipment via the case of the antenna tuner.
I had to send my HF radio, 2 meter radio , and power supply away to be
repaired. My computer was ruined and had to be replaced. Lucky for me
my homeowners insurance covered the repairs and a new computer.
(plus I was home to catch this happening... the house could of caught
on fire if I was gone !!!)

Do what Tom says and "just throw the feedline out the window". I always
disconnect mine now....

                      Jeff KU8E

> Hello All,
> I have been enjoying this list, especially recently with all the text
> about grounding. My question is about how anyone is grounding 450-ohm
> line as it enters the house. My antenna is only up about 30 feet, so
> maybe not a big lightning risk, but I am concerned just the same. I
> did have the line coming in a basement window, then a small knife
> switch with one side connected to the cold water pipe - I was uneasy
> about bringing lightning inside for that.

I'd disconnect it outside, and let it lay away from the house if 
possible. I would not ground it to anything, as long as I could get 
the wires loose and away from the building and away from valuable 

Short of that, I'd use a spark gap. The problem is with open wire 
line the voltages can be very high even with modest power, so you 
sometimes need a very large gap!

Open wire or ladder line, or a single wire feed, are probably the 
worse things in the world to handle short of tossing em out in the 
yard before storms arrive. DO NOT depend on a ground, especially 
through a balun or small switch! A knife switch would never work 
reliably on a nearby or direct hit.


   73, Tom W8JI 

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