GD Tom,
I have had the experience of vaporizing antennas a couple of times.
The first time I saw such a thing happened back in the mid '70's when
my neighbor's 75M dipole disappeared during a very violent
thunderstorm. I went to check and the #12 AWG antenna was simply
gone, leaving only the coax and puffs of monofiliment line from the
exploded closeline that he had used to support both ends of the
antenna. The end of the coax was melted and we never found the
insulator. The other end of the coax, which had been disconnected
before the storm, was welded to the metal leg of the operating desk
and there were burn marks on the floor. That lightning event very
nearly became a house fire.
The second time happened to me in the form of a 400' 17-AWG galvanized
Beverage that vanished during a violent thunderstorm about five eyars
ago. There was a loud bang in the middle of the night and I smelled
smoke, which turned out to be an extremely fried antenna switch. In
the morning, I could not find any trace of the antenna, its matching
transformer, or the termination resistor. The coax was melted on both
ends and the jacket perforated every few feet from the standing wave
voltage loops punching through the jacket to ground.
I do think the weather has become more violent over the past decade or
so. The derecho event last week was an eye opener, as I lost all my
Beverages to falling trees, as well as my Battle Creek Special that
had stood up to everything until now. I am off the low-bands for a
bit. It will take months to repair all the damage, but at least the
lightning threat should not be an issue.
73,
Steve
AB4I
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Message: 5
Date: Sun, 8 Jul 2012 09:34:27 -0400
From: "Tom W8JI" <w8ji@w8ji.com>
Subject: Topband: Lightning makes antennas vanish
To: <Topband@contesting.com>
Message-ID: <C03E04344D964684815C90E9E0D1B22C@tom0c1d32a93f0>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I've never experienced this before a year or so ago, when I had a Beverage
antenna melt in two from a nearby tree getting hit.
About a month ago I had about 300 feet of a Beverage just vanish from a hit
on a tree next to the wire.
Now it happened again this week, and long stretches of two Beverages just
vanished. This is cad plated #17 electric fence wire.
Anyone else have this happen? My copperweld #14, that clearly has arc
pitting where it passed over other wires, shows no damage other than the arc
pits. The cad-steel fence wire must get so hot it just vaporizes. I can't
even find any pieces of it.
Since the 1960's or 70's, this is the very first time I've seen this happen.
Are thunderstorms more violent now, or is wire cheaper? :-)
I'm not fixing my antennas until October or November.
73 Tom
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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