[TowerTalk] Fwd: Lightning protection - length of grounding rods runs from tower?

[Hans Hammarquist via TowerTalk]

Ray,


With your ground conditions I would make .. sure to have a very good connection between the tower and the shack ground. I myself have a 6" wide aluminium strip (not aluminum foil but of an aluminum sheet) between my tower and the shack ground. I also used 9 grounding rods, each 4 feet down around the tower, That's the only grounding for my shack - tower. The power line has a safety ground but I believe that I should (any day now) connect the house ground with my shack/tower ground with a heavy wire/strip.


If the lightning strikes the tower you want to make sure to minimized the voltage potential between the tower and the shack (and whatever else is connected). I have no other suggestions. I suspect you will have a tough time to make any good ground connections the way you describe the ground conditions around your location.


Good luck with your installation and best 73 de,


Hans - N2JFS 










-----Original Message-----
From: Ray Benny <rayn6vr at cableone.net>
To: TowerTalk <TowerTalk at contesting.com>
Sent: Wed, Jan 28, 2015 7:37 pm
Subject: [TowerTalk] Lightning protection - length of grounding rods runs from tower?


I am about to start the grounding system for my 90ft free standing tower. I
do have the Ufer ground / rebars connected to the tower. The next part is
to run 'spokes' of ground rods out a distance from the base of the tower.
Ground rods are connected with #4 copper wire with Cadwell thermal devices,

My question, or request for your thoughts, is it better to run 3 grounding
wires out 40, 50 or 60 ft (8 ft ground rods about every 16 ft connected
with bare #4 wire) or to run say 6 ground wires out, perhaps 30 - 40 ft
outwards? I have room in all but one direction to trench out a 100 ft if
that would be even better yet.

I'm in the Arizona high desert, at 5000 ft. My soil is hard packed dirt and
conductivity is very low, with no moisture at all, except during our winter
storms and summer monsoons. Its takes about 5 minutes to drive an 8 ft
ground rod with an electric impact driver. Water level is about 350 ft.

Your thoughts and knowledge please.

Tnx,

Ray,
N6VR
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