In a message dated 2/24/02 4:22:30 PM Pacific Standard Time, rfman@nc.rr.com
writes:
> My shack is constrained to the second floor. This means that my ground will
> be long (approximately 15 feet). I CAN'T CHANGE THAT. I can run
additional
> radials around the shack floor edge and into a walkout area over the
garage.
>
> My service, telco, and cable entrance is on the opposite side of the house
> (of course :-). This means that I will have to take some #6 or better
(both to
> meet code and to do any good) and run it around the house to connect my
> shack/antenna ground and the other grounds. What a pain. But I see no
alternative. > We are talking about approximately 110 feet.
>
Well, the purpose of a good Single Point Ground System is to keep the
lightning transients OUT of the house so if you do that, what happens IN the
house is not as bothersome.
You can't obtain a very useful shack ground because of the distance
anyway. The inductive resistance (I think that's the proper unit) of a foot
of good-sized wire is relatively high so it's not going to encourage any
charges to follow it to ground - particularly if it's on the second floor.
Bring the cables in where you need them via your SPGS ground bus, have 3
ground rods under the ground bus, and then tie the bus ground into the
utility grounds via a big bare, buried solid wire with either exothermic or
compression connections and you should be in good shape.
The main point is that you want the potential of everything that may be
part of the lightning charge to rise and fall at the same rate - that's why
you tie it all together. If you've got that and you keep the transients out
of the house, then you've won.
Cheers,
Steve K7LXC
Tower Tech
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