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Re: [TowerTalk] Static, Lightening, and protection

To: Tom Champlin <w0hh@msn.com>, towertalk@contesting.com
Subject: Re: [TowerTalk] Static, Lightening, and protection
From: Doug Renwick <ve5ra@sasktel.net>
Reply-to: ve5ra@sasktel.net
Date: Mon, 22 Mar 2004 09:10:26 -0600
List-post: <mailto:towertalk@contesting.com>
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.

_______________________________________________

See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

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