Tom wrote: "The data was derived from a map of recorded lightning hits, and
comparing concentration of hits to heights of towers. One thing specifically
discussed in these links was a water tower that was erected near a house. They
were very good in their methodology, so I have no reason to doubt the accuracy."
Tom... I took a look at the data on the two sites you mention.
The first one reports how well grounded lightening rods curbed the damage the
wind generator towers were experiencing from lightning strikes, bringing the
damage to near-zero incidence. But I saw no data that addressed the number of
lightning strikes before or after the installation, they just talked about
damage mitigation. I saw nothing there that says how often the ground around
the towers was struck vs how often the towers were struck.
The 2nd site speaks to geographical influences on lightning strike density, and
it's on a large scale... covers areas much larger than an antenna field. It
also doesn't say anything specific that I could find about the topic we had
under discussion, just general trends. There's lots of the maps of you mention,
but I didn't see anything "comparing concentration of hits to heights of
towers" as you stated.
And, I didn't find anything on the Polyphaser site (other than grounding, on
which everyone agrees) that deals with pre-strike means to lessen the risk of a
strike, just methods and products for post-strike mitigation.
But perhaps I perused them too quickly. I'm sure if you relied on specific data
it must be there somewhere. Could you please extract the pertinent data for me?
Maybe your eyes are sharper than mine.
See, all due respect and no offense intended, I don't think you (or others)
have any more real, hard, pertinent, reliable, data on pre-strike factors than
I do, yet you (and others) insist on making definite, specific, authoritative
pronouncements about the subject. I don't say you (or others) are wrong, just
that you (like me) don't really know for sure, and one can't convincingly
refute ideas without presenting some hard, pertinent data.
Here's a site that seems to have hard data to support its products, which look
remarkably like "spiderballs" and are in wide industrial use as a way to lower
the risk of a damaging strike. They offer pre-strike risk reduction with
products approved by the Underwriters Lab. I have no independent knowledge of
whether or to what degree they might work, but I seriously doubt this company
would have been in business for 30+ years if their claims were just hooey.
http://www.lightningeliminators.com/technica.htm
73, Jerry K3BZ
----- Original Message -----
From: Tom Rauch
To: Jerry Keller ; kk9a@arrl.net ; TOWERTALK@contesting.com
Sent: Wednesday, July 28, 2004 9:34 PM
Subject: Re: [TowerTalk] spider balls
Because it's from you, Tom, I'm willing to accept that, but
I wonder:
1. Where does one find the data to which you refer?
2. Who are the researchers?
3. When was the data compiled?
4. How was the data gathered?>>
The links for this were all on this thread very early on. I
believe it was K1TTT that posted that particular link, but I
may be mistaken.
The data was derived from a map of recorded lightning hits,
and comparing concentration of hits to heights of towers.
One thing specifically discussed in these links was a water
tower that was erected near a house. They were very good in
their methodology, so I have no reason to doubt the
accuracy.
The other information is in the technical articles on the
polyphaser site.
Links people post here are generally very educational. If no
one pops up with the link(s) again, I guess I can search the
archives and find it again or you might have a look back.
I'd like to add:
http://www.nrel.gov/docs/fy00osti/28604.pdf
Which if you look at the data shows the number of hits in
farms of wind turbines is roughly proportional to the
frequency of lightning hits in the area. No "quiet zone" in
turbine farms from multiple towers or grounding!
and
http://www.nssl.noaa.gov/wrd/wish/kaney/light/light.html
73 Tom
_______________________________________________
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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_______________________________________________
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.
_______________________________________________
TowerTalk mailing list
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