Every time Towertalk starts off on one of these threads I feel compelled
to add one skeptic's viewpoint, and this time I'm actually going to do it.
Unless you are an electrical engineer with deep understanding of
lightning protection, I think that attempts to replicate a commercial
24/7 always-connected solution are far more likely to fail than to
succeed. Rhetoric about causing all the grounds in a station to rise
and fall together during a strike is fine, but how much voltage
difference does it take to damage ICs and semi-conductors?
I am *not* that engineer, so I decided 17 years ago that my installation
would have quick-disconnects for every conductor coming from the tower,
at the panel where they enter my second-floor shack. I leave them
disconnected except when I am on the air. I should probably have the
disconnects at ground level, but I felt I would be more likely to
disconnect them if they were right at hand.
A few years ago, I took a direct hit on the top of my tower, some 190
feet from the house. I was in the shack at the time, and the SO-239
connectors on my entry panel arced with a loud bang. Both rotators, a
stackmatch and a remote antenna switch were damaged, and a loading wire
on my 40-meter yagi was severed, but the only damage in the house was to
two computers on an Ethernet network, both of which were fried by
induced voltage on the network wiring, and my telephone answering
machine. I was well pleased with this result, as was my insurance agent.
73, Pete N4ZR
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On 7/4/2013 4:26 PM, Jim Lux wrote:
On 7/4/13 1:09 PM, les wrote:
Is it better to place lightning protecting at the base of the tower or
where it enters the house. All cables will be in a buried conduit.
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The electrical code, which is worried about structure and life
protection, requires it at the entry point to the structure.
If you have a long run underground between tower and house, then there
is some advantage in also having protection at the base of the tower,
on the assumption that the coax on the tower would be destroyed, but
the coax underground would be saved.
I'm not sure about that.
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