> My tallest tower is now only 85 feet tall, yet I have had towers
> above tree level for almost 15 years and have yet to experience a lightning
> hit. The towers are grounded, yet I am not sure how good the ground is at
> this point in time. To what do I attribute my lightning-free experience?
> Only Divine providence. However, the moral of the story is that you should
> not expect to be safe from lightning strikes simply because there are taller
> objects nearby than your tower.
well, maybe divine prvidence and a bit of statistics.
consider a 30m high tower. use a 45 degree angle down from the top of
tower (a 45 degree angle is a commonly used estimate for how big of an
is 'protected' by a tall pole or wire). This means that any stroke in
area of about 2800 square meters around the tower may strike the tower
instead of the ground. i don't remember the statistics for your area,
out here in western mass there are about 4 strokes per square kilometer
year on the average. this means 4 strokes in 1,000,000 square meters
year.... so your 2800 square meter area would get 4*2800/1000000 or
.0112 strokes per year, or about one stroke every 89 years that may hit
tower itself, or may ignore it and still hit the ground.
David Robbins K1TTT (ex KY1H)
email@example.com or firstname.lastname@example.org
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com