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[TowerTalk] Ground rods

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Subject: [TowerTalk] Ground rods
From: raylarue@gte.net (Ray LaRue)
Date: Wed, 16 Apr 1997 09:17:01 -0700
Have been reading the several comments about grounding for towers.  For 
those souls who live in Central Florida (the lightning capitol of the 
world?), and other similar ground areas, I thought I'd share a bit of my 
experience on the subject.  I hope it will be of some help to others who 
might be lulled into thinking 1 ground rod is sufficient.  

After moving to my present QTH a few years ago, I quickly put up my 68 
foot tower and drove a 10 groud rod at the base.  A while later, I became 
concerned about the ground conductivity of the sandy soil here and 
borrowed a ground tester from a friend at the power company.  What I 
measured on my 10 foot ground rod, was 750 ohms!  Being quite surprised, 
I decided I had to go deeper, I secured some threaded rods and couplers, 
and an electric driver.  I had to drive 55 feet to get a 5 ohm ground.  
You could see quite easily where the ground impedance started to fall 
(getting into moist earth), at about 45 feet. I eventually drove 4-50 
foot plus rods, with 1 at the tower and the others about 40 feet, and 
axial, from the base.  I then bonded them together with 4-0 copper 
stranded wire, buried in the ground.
 
Maybe some will say that was a bit overkill.  I'm not sure it is for this 
area.  Let me suggest a conversation with some of the local power company 
outside installers and techs, can be quite helpful for what is typical 
for your area.  But a single rod should be viewed as a very questionable, 
and certainly as minimal, for lightning protection and/or a good RF 
ground.  

I hope this is helpful to anyone who might be concerned with such things. 
  
73,
Ray, W4BYG

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