Re: [TowerTalk] Static, Lightening, and protection

[Doug Renwick <ve5ra@sasktel.net>]

Theory is only theory and a starting point for an investigation.  Experience is
the dominating factor.  Tom's experience is opposite to what my experience has
been.  First I live in an open space and my towers are the highest structure 
around.
Second I have never had any lightning damage in 27 years.  My towers are over
100 ft and I purposely make sure the mast extends well above the tower and 
antennas.
The top of the mast is capped to a rounded point and may contain a porcupine.
My towers are only grounded below and through the concrete base to 2 ground
rods installed before the concrete was poured and attached to the tower legs.
I get a lot of static discharge from only my largest tower/array and a wonderful
'cone of protection' for everything around.  Somewhere else this may not work.
But it sure works here and saves a lot of money and work putting in an elaborate
lightning protection system which may or may not be necessary.

Doug

Tom Champlin wrote:

> No one can predict what lightning will do, regardless of whatever protective 
> mechanism is used, or regardless of the theoretical prowess of the designer. 
> I have observed many hams who have a yagi above their tower, but do not have 
> the 20 foot 2 meter shaft above the yagi who have never had any lightning 
> problems. I also know hams who did have this big lightning rod above their 
> yagi who lost the whole station. After personally inspecting such an 
> installation that had just been hit, I decided to never have anything above 
> the yagi except maybe 5' of mast for the truss. In 13 years, I have never 
> had a hit. I do use heavy solid copper radials and 3 ground rods under the 
> tower to help dissipate a strike should one occur. I also use the Polyphasor 
> coax lightning arrestor which may be of some value.
>
> 73, Tom W0HH

--
Doug Renwick VA5DX
PO Box 50, Clavet, Saskatchewan, Canada S0K 0Y0
VE5RA@sasktel.net
First VE5 9BDXCC
What profit it a ham if he gains all the awards yet forfeits his soul?
I'll run the race and I will never be the same again.

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