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## [TowerTalk] More comments on lightning - second hand from an expert

 To: [TowerTalk] More comments on lightning - second hand from an expert k1ttt@berkshire.net (David Robbins) Thu, 04 Jun 1998 00:54:55 +0000
 ```dave@egh.com wrote: > 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 the tower (a 45 degree angle is a commonly used estimate for how big of an area is 'protected' by a tall pole or wire). This means that any stroke in an 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, but out here in western mass there are about 4 strokes per square kilometer per year on the average. this means 4 strokes in 1,000,000 square meters per year.... so your 2800 square meter area would get 4*2800/1000000 or about .0112 strokes per year, or about one stroke every 89 years that may hit the tower itself, or may ignore it and still hit the ground. -- David Robbins K1TTT (ex KY1H) k1ttt@berkshire.net or robbins@berkshire.net http://www.berkshire.net/~robbins/k1ttt.html -- FAQ on WWW: http://www.contesting.com/towertalkfaq.html Submissions: towertalk@contesting.com Administrative requests: towertalk-REQUEST@contesting.com Problems: owner-towertalk@contesting.com Search: http://www.contesting.com/km9p/search.htm ```
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