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Re: [TowerTalk] Lightning damage to rotor housings(Was:Whichthrusebearin

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Subject: Re: [TowerTalk] Lightning damage to rotor housings(Was:Whichthrusebearing?)
From: "K8RI on TowerTalk" <>
Date: Fri, 15 Dec 2006 01:00:04 -0500
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In all my years on the air I have never had a rotator or control box damaged 
by lightning. That's not saying I won't lose them all next summer, but so 
far...  As others have already said, the strength of lightning strikes 
varies widely and the stuff is very unpredictable.

Another note, I agree with someone who said the copper cable down the tower 
would be a waste of time as the tower would provide a lower inductance path.

I've had all kinds of wind damage to the rotator proper as well as a recent 
seal failure letting water in one, but nary a lightning problem.  I say that 
knowing this system has taken an average of 3 confirmed "direct" hits a 
year. This past summer was a bit above average with 5 hits (all before mid 
July). I've replaced a few coax connectors up there that looked like they'd 
been etched from the corona.

Relying on a memory getting older and shorter: Due to lightning I've lost a 
couple of big verticals, had a piece of 7/8" Heliax blown out about 20 feet 
below the top of the tower, one blown balun, one blown ferrite choke, two 
Polyphasers on the 440 antennas in two consecutive years, and one N-Type 
double female barrell connector shorted.  Very early on before the ground 
system was finished I also lost one *new* computer and the front end out of 
a 2-meter rig from a direct hit to  the tower.

BTW all that damage (with the exception of one Polyphaser) was when I had 
the old tower up, a repeater antenna on top, and was using a Ham IV to turn 
a Cuscraft ATB34. The rotator had been up nearly 15 years and the outside 
looked it, but it still worked fine.  I replaced the big commercial repeater 
antenna with a Diamond after the hit that took out the Heliax. A year later 
I replaced the Diamond with a Comet I had up just above the roof after the 
Diamond was blown apart.

I'd really like to put one of the Diamond or Comet 144/440 verticals on top 
of the present system, but I think that'd be a lost cause.

Since completing the ground system there have been many direct strikes with 
no damage. However if it ever takes one of the so called "super strikes", I 
think it'll be time to call the insurance company and a construction crew.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2


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