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Re: [TowerTalk] Ground Rods

To:, <>
Subject: Re: [TowerTalk] Ground Rods
From: Jim Lux <>
Date: Tue, 04 May 2004 09:53:35 -0700
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At 08:07 AM 5/4/2004 -0700, Bill Turner wrote:
On Mon, 3 May 2004 18:38:26 -0600, Grillo's wrote:

>One of the calculations I was looking at can drop impedance from 300 down to 5 ohms with using only 4 of these rods.


This reminds me of the school of thought that says the connection to
your ground rods must be tight.  As if lightning, having traveled
thousands of feet through the air, is going to be stopped by a gap of a
few thousands of an inch.

I suspect that this is for dissipating an induced voltage (not a direct strike). As a practical matter, there are probably more "nearby" strokes that cause problems than direct hits.

Direct hits are more rare (difference between being the bullseye and hitting the target anywhere)

With a direct hit, as you say, the lightning finds a path to ground, and if your equipment gets damaged, it's probably not a little damage, but a significant "exploded front end" kind of damage.

With an adjacent hit, where you just got a few kV (or even a few hundred V) transient on the antenna connector.. enough to cook the input mixer, perhaps partially, or to partially cook something else.

The advice to ground the radio input when not in use comes more from the "protect the delicate receiver from middling transients" than the "protect the rig from exploding in a direct hit".


See: for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

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