[TowerTalk] lightning umbrella

[Keith Dutson]

>MY experience has been just the opposite through a number of lightning
strikes.

My experience is similar.  There have been five observed direct hits to the
tower.  Damage was sustained in the house and shack from one of these.
However, this problem was traced to a grounding problem at the house AC
mains that allowed induced voltage to follow power, phone and LAN cables
from the house to the shack, wiping out several computers and phones plus
the AC circuit boards in the Alpha amp and Icom transceiver.

Keith NM5G

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of W0UN -- John
Brosnahan
Sent: Saturday, February 26, 2005 3:44 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] lightning umbrella


>
>My interpretation of the zone of protection would be, if your house is 
>anywhere WITHIN that radius, you are MORE likely to be hit than if the 
>tower were located further from the house, outside the 'protection' 
>radius.

MY experience has been just the opposite through a number of lightning
strikes.  (I know there is no rule that says there will never be exceptions
and this claim is supported by only a few incidents.)

My house in CO is on a little hill.  Probably 25 feet or so above most of
the surrounding area.  Also on this hill is my 175 ft rotating tower, within
about 35 ft of the house.  The tower is well grounded with a total of NINE
10ft ground rods and a radial system interconnecting them.

This was felt necessary because the soil has such poor conductivity -- being
mostly sand and sandy loam.

I also have a steel building that about 200 ft from the tower.
The building is in an low area and the highest points of the building are
well BELOW the level of the earth at the house and tower.

I have never had any hits to the tower or to the house since I installed the
tower, at least that I know of, and I have never received any damage to the
house or equipment.  But the steel building has been hit a couple of times,
the most recent was on the "arm" that supports the yard light on the end of
the building closest to the tower.  Now there is a lot of conduit in the
barn that only has remnants of TW wiring.

I feel that I have enough experience to believe that the cone of protection
concept is actually true.

--John  W0UN


_______________________________________________

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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