[BC] Lightning

[Bruce Doerle]

Excellent point Lamar!

We use nineteen ground rods on our system in Orlando and it has been recently supplimented with about twelve more curtiousy of T-Mobile around their installation to our tower.

Thanks, you validate my points,

Bruce

>>> lowen at pari.edu 05/25/05 7:40 PM >>>
On Wednesday 25 May 2005 18:52, Kevin/Tieline Technology wrote:
> Wow, then how DO you deal with multiple hits in a place like Florida?
> Do you have to rebury the ground rod now and then?  I would think the
> ground resistance meter that the power company folks have would be real
> valuable for you then.  Curious to know the answer!

The packet Nautel ships with their new transmitters has (or at least used to 
have) in it the PolyPhaser manual.  This is a good read.  The basic idea is 
multiple rods, spaced to prevent overloading the ground (glassification is a 
clue that the ground was overloaded), star grounded to a single bonding 
point.  Grounding is quite literally a matter of surface area; the resistance 
of soil is quite high, and in order to prevent overload one must reduce the 
current the rod must handle; the only way to do this is multiple rods. See 
http://www.polyphaser.com/ppc_ptd_home.aspx for a list of free publications, 
or buy the book "The 'Grounds' for Lightning & EMP Protection" (out of print, 
but available from several sources, including Amateur Electronic Supply 
(www.aesham.com)) for $20.
-- 
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
(828)862-5554
www.pari.edu