In looking over all the posted responses, it appears that none of these
fellows care much about lightning protection. There are many articles
published and all agree that all cables on the tower should go down to
ground level at the tower base. This is a basic and necessary procedure in
creating a system that "might sustain" (with lots of additional work,
expense, and luck) a lightning strike. When ignoring this detail, all other
attempts at preventing equipment damage are essentially a waste of
resources. If the cables leave the tower at roof level, lets say 10 ft.
above the ground, use ohms law to figure how much of a voltage rise occurs
in those cables assuming only 1/10 of an ohm resistance in all the cables,
with the magnitude of a multi 100KV lightning strike. At the base of a
"properly grounded" tower you should have zero ohms to ground and no
potential on the cables when using adequate protection at that point.
Somewhat safer than the prior example which would likely destroy much, if
not all of your ham equipment, many other sensitive electronic equipment in
and around your house, and maybe the house itself!
I can't believe how many people do this! Can't say you haven't been warned.
I don't know if there is anyplace where lightning considerations shouldn't
be a factor in the construction of a ham antenna / station, but living in NE
Florida, its a HIGH priority for me here but I've still seen many cables
coming off towers as you propose. No, I've never had a hit that I was aware
of, and like it like that. The alternative could be lethal!
73, -=Roger-K9RB=-
-----Original Message-----
From: MBecker@aol.com <MBecker@aol.com>
To: towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Tuesday, September 08, 1998 11:06 AM
Subject: [TowerTalk] Running Cables Into Shack
>
>Hi all,
>
>I am trying to figure out the neatest way to bring my antenna cables into
my
>shack. They will be running across the inside of my attic and I would like
to
>drop them into the shack through an opening in the ceiling. I live in a
one
>story ranch and I can get directly above the shack easily. I don't think
the
>XYL would appreciate a plain hole drilled in the ceiling so I need a way to
>neatly do the job. Any thoughts?
>
>Thanks,
>Mike, KT3U
>
>--
>FAQ on WWW: http://www.contesting.com/towertalkfaq.html
>Submissions: towertalk@contesting.com
>Administrative requests: towertalk-REQUEST@contesting.com
>Problems: owner-towertalk@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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Search: http://www.contesting.com/km9p/search.htm
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