This is a multi-part message in MIME format.
--part0_896888912_boundary
Content-ID: <0_896888912@inet_out.mail.aol.com.1>
Content-type: text/plain; charset=US-ASCII
--part0_896888912_boundary
Content-ID: <0_896888912@inet_out.mail.aol.com.2>
Content-type: message/rfc822
Content-transfer-encoding: 7bit
Content-disposition: inline
From: TOMK5RC@aol.com
Return-path: <TOMK5RC@aol.com>
To: tower-talk@contesting.com
Subject: Re: [TowerTalk] Lightning solution
To: <towertalk@contesting.com>
Date: Wed, 3 Jun 1998 11:45:29 EDT
Mime-Version: 1.0
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7bit
In a message dated 6/3/98 8:19:58 AM Pacific Daylight Time,
10eesfams2mi@mass1-pop.pmm.mci.net writes:
<< He says it works
because his 40 foot tower in the middle of the 90 foot tall trees
has NEVER been hit. >>
I've never had damage to my home from an elephant stampede, either.
Protecting ourselves from lightning is 50% science and 50% random perversity.
For 20 years, K5LZO lived in an innocuous location, not particularly high,
plenty of trees, towers, light poles, etc., in the area. He had 4 towers, from
50 to 100.' He sustained 13 direct lightning hits in those 20 years. It hit
the towers, satellite dish, house, power lines, phone lines and anything that
was metal.
During those same 20 years, I lived across town, had as many as 11 towers in
the air, from 50' to 185,' lived on open prairie, usually the only metal in
the area. In that time, I had lightning hit the power transformer next to the
house and burn up the electric range. I also had one rotor control box that
may or may not have been damaged by lightning. I took no particular
precautions, except for a good ground at the shack. I used home made switch
boxes. All feedlines were hard wired to the boxes and the only safety
precaution was that the relays all opened when the power was turned off. At my
last QTH in Texas, I had a repeater antenna at 140,' connected and active 24
hours a day for 5 years. Even though we had lightning storms almost weekly,
the antenna took only one known hit and damaged the last 18" of the vertical.
There was an ICE surge box connected to a ground rod and installed at the
duplexer and there was no damage to the duplexer nor the repeater.
Go figure.
In the last few years, we have become more aware that lightning behaves much
like RF, propagating down the outside surface of metal objects, looking for
"ground." Beyond that, protecting yourself from lightning is a matter of
degree of comfort, experience and budget. K5LZO is totally gun-shy about
towers and lightning. I am more philosophical and just take the precautions
that I am comfortable with. Hopefully I will have elephant damage and
lightning damage about the same time. Maybe not.
Tom, K5RC/7
On the Comstock
--part0_896888912_boundary--
--
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
|