The Polyphaser book recommended ground rods spaced at 2x the length of the
ground rods. The purpose was to spread the charge out in the event of a hit.
So is that theory or explanation now out, disproved, or ...?
It has been a long time since I looked at the book so I may not have
remembered it correctly.
73, Larry W6NWS
-----Original Message-----
From: Mike Reublin NF4L
Sent: Thursday, January 29, 2015 7:42 AM
To: Ray Benny
Cc: towertalk reflector
Subject: Re: [TowerTalk] Lightning protection - length of grounding rodsruns
from tower?
My electrician (who is regarded as a grounding expert here) told me the
extra ground rods would add absolutely nothing to the protection provided by
the Ufer ground of the base. OTOH having the rods wouldn't hurt anything.
Since he'd charge me to drive 'em I decided to forego them. He megged the
tower at 4 ohms. Water level is about 3 feet.
73
Mike NF4L
On Jan 28, 2015, at 7:37 PM, Ray Benny <rayn6vr@cableone.net> wrote:
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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