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[TowerTalk] grounding

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Subject: [TowerTalk] grounding
From: (Pete Smith)
Date: Wed May 21 07:01:18 2003
At 09:30 PM 5/20/03 -0500, Wes Attaway \(N5WA\) wrote:
>Going from a second floor room to ground for the
>purpose of a so-called DC ground is not much of a problem.  Your
>coax should be grounded near the ground out at the tower, and
>maybe again just outside the house before coming up to the second
>floor, so I don't think it would much of an issue as far as the
>second floor goes. DC grounding and RF grounding problems are two
>different animals.

But lightning is much more like RF than DC, according to the Polyphaser 
book, because of the short rise-time.  That's why they put so much emphasis 
on the use of short, wide, straight (low-inductance) copper strap for 
grounding their SPG bulkheads.  I understand that hypothetically you could 
have a situation where a strike caused all the grounds in a station to rise 
to the same (relatively high) potential, and because there was no 
difference between them no damage would occur.  But frankly, I'm not that 
confident of my ability to make that occur.

It seems to me that all this is a matter of probabilities.  Since I don't 
need 24/7 operational capability, I would rather disconnect all conductors 
going to my tower, in the belief that any direct strike or serious induced 
voltages are much more likely to arrive in my shack by this route.  My AC 
service has a whole-house surge protector, all items in the station are on 
surge-protector strips, and my telephone line also passes through a surge 
protector.  I'm sure there are still scenarios where I could sustain 
damage, but I think the likelihood is acceptably low.

73, Pete N4ZR
The World HF Contest Station Database was updated 9 May 03.
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