The Polyphaser book suggests several lightning rods spaced at twice the rod
length for some distance out from a tower in several directions. It
presumably spreads the charge of a strike out if I recall. (It has been
several years since I read the book last.)
73, Larry W6NWS
-----Original Message-----
From: Jim Lux
Sent: Monday, August 20, 2012 4:40 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Info/Advice re: Exothermic Welds
On 8/20/12 10:54 AM, Art Greenberg wrote:
>
>
> I imagine that the single-shot mold might be faster to use but more
> expensive than a reusable mold. If each trench run is 100 feet and I use
> 10-foot ground rods spaced at 20 feet, that's a total of 12 ground rods to
> bond to including the existing electrical service ground.
It's not entirely clear why you would want to put a rod every 20 feet on
a buried conductor. The wire laying in the trench itself isn't a bad
ground conductor.
Some sort of grounding electrode at each end is probably what you want.
And for lightning ground, strap doesn't buy you much over round wire.
>From a lightning standpoint, the inductance is what's important and the
inductance of strap and round wire is pretty similar. (AC resistance is
lower for strap, so if it's part of your radiating systems: e.g. a
vertical antenna ground system, then strap might make a difference)
" The entrance
panel will contain a grounding plate on which lightning arrestors are
located, and I'll run a ground wire (or a wide copper strap) from the
grounding plate to that ground system, and to my electrical service ground
rod. "
For this, wire is the way to go. The AC resistance isn't the dominant
thing to worry about.
Of course, if you've got a pile of strap for other reasons, then you
might want to use it.
I've seen schemes where people curl the strap up and braze it to another
conductor, or wrap the strap around something like copper pipe or AWG2
stranded, and braze/hard solder it.
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