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Re: [TowerTalk] tower ground question

To: jim Jarvis <>,
Subject: Re: [TowerTalk] tower ground question
From: David Gilbert <>
Date: Thu, 29 May 2008 01:45:31 -0700
List-post: <">>
Jim Jarvis wrote:
> The idea is to provide a low impedance path AROUND the concrete  
> foundation
> for lightning to get to ground, not THROUGH it.
Why?   If it is indeed a low impedance path (and it would be useless if 
it wasn't), why is it less desirable to run it through the concrete than 
around it?
> Personally, I would not attach the rebar to the tower at all.   To do  
> so only makes
> that a more viable path for lightning. 
Why?  The tower legs (or the tower base or the tower mounting bolts) are 
already embedded far into the concrete and they arguably form the lowest 
possible impedance path INTO the concrete.  Besides, Polyphaser strongly 
recommends making a Ufer ground out of the rebar cage specifically for 
the purpose of lightning protection (see  In 
fact, my local zoning department INSISTED that the tower be bonded to 
the rebar cage.

>   In addition, the corrosion  
> which will take place
> with the copper attachments will assure that in 10 years, those  
> embedded connections
> can't be trusted.
That's why Cadweld connections should be used to bond to the rebar, and 
it isn't any more difficult to do that than to bond the ground wires to 
ground stakes.  I bought the mold and materials to do so on eBay for 
less than $30.

I keep seeing this same discussion pop up time after time, and yet I've 
never seen a single coherent, fact-based argument why a ground wire 
should not be run through a concrete tower base.  Lots of people claim 
to have heard about a tower base that exploded for that reason, but even 
Polyphaser says they haven't been able to confirm any instance of it 
(they call it a myth).  I installed a tower and antenna system at my own 
QTH over the last few months --- I bonded the tower base to the rebar 
cage and ran six ground wires from the tower out through the side of the 
concrete base to be connected to ground rods in a radial pattern.  
Pictures of the entire installation can be found at  We get some major lightning storms here in 
southern Arizona during our summer "monsoon" season and if my concrete 
explodes I'll be sure to let everyone know and add pictures of it to the 
web site, but in the meantime it would be nice to see this discussion 
revolve around facts instead of urban legends.

Dave   AB7E


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