I don't think tying anything together that is more than 80' apart does
anything, because I believe the energy from the stroke will go somewhere
else quickly, rather than patiently traveling out the end of one ground
system and trying to all flow to another. Think UHF techniques where a 6"
piece of wire is a major inductance. A 30' piece of wire (even #00) is for
all practical purposes a choke. I like the grounds independent and having a
common point only in the entrance panel to the shack, which becomes the
reference point.
In very low conductivity soil, I think all you can do is have lots of
surface area for the energy to spread out on, and a low inductance path for
the spreading to occur. The coax to the shack is a much higher impedance
path than the ground system, so it is not a likely path. I like to bury the
feed lines and control cables, but still use isolators at the point where
the feed lines enter the shack. I operate 95% of the time remote, so I can't
go out and disconnect things when a storm comes up: it is on all the time.
I have had one direct hit on the tower with no damage. I have seen energy
from a stroke take a very unlikely path and do lots of low probability, but
very real, damage. I figure that having the round rods farther apart would
just isolate them and essentially place "chokes" between them, so in low
conductivity soil, I like spacing approximately equal to the length of the
rod. BTW, rods are impossible to drive here, and my rods are placed in 2"
diameter holes drilled in the rocky soil and back filled with Bentonite.
-----Original Message-----
From: Dick Green [mailto:dick.green@valley.net]
Sent: Thursday, August 12, 1999 9:56 AM
To: John Langdon; wa4dou@excite.com; towertalk@contesting.com
Subject: Re: [TowerTalk] RE: Tower Grounding Query!
I have some additions questions on this subject.
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