[TowerTalk] New Tower Construction - Questions

[K7LXC@aol.com]

In a message dated 08/30/2000 3:43:45 PM Pacific Daylight Time, N8NGA@one.net 
writes:

> A)  It is advisable to use the rebar cage as PART (not all) of a grounding
>  system.  Lightning will in fact go through the tower to the rebar and
>  the concrete for a ground.  (interesting note, most building
>  departments now require the rebar in concrete swimming pools to be
>  grounded).
>  
>  B)  The concrete, under certain conditions can, in fact, explode
>  exactly as I described and for the reasons I described.   When a
>  proper system is done, though, the chance of this happening is very
>  slim.
>  
    The central issue in using the rebar/base as part of a grounding system 
is that it all has to be bonded properly. Simpy using wire ties won't do it - 
everything will still arc. It has to be an exothermic bond like CadWeld or 
similar or it needs to be brazed or welded somehow. I've seen discussions of 
why you shouldn't braze/weld rebar but IMO it's still better than wire-tying 
everything. Most hams won't spend the time or money to use CadWelds and don't 
know how to braze/weld so I would not recommend doing it that way. Installing 
ground rods is easier and can be done by just about any ham so that would be 
my suggestion.  

Cheers,   Steve   K7LXC
Tower Tech 

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