I agree with this assessment. My club has a 2 meter repeater located on a
tall building in Houston. The antenna sits on top of the building, mounted
to a metal facia running around the perimeter of the roof. So far, the club
has bought an average of one antenna per year due to destruction by
lightning.
Two years ago our repeater trustee happened to meet another fellow with a
similar problem. His solution was to install a lightning rod slightly above
the antenna and connect to ground with 4 gauge copper cable. We now have
one of these and the antenna has been spared for the last 24 months.
Keith
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Kevin Hemsley
Sent: Wednesday, July 07, 2004 1:39 PM
To: Towertalk
Subject: Re: [TowerTalk] lightning frequency and towers
There is a very interesting short paper on this site that is directly
related to the recent lightning thread: "Towers, Lightning and Human
Affairs". Here is a quote from the abstract which is discussing "ham radio
towers, water towers, microwave repeater and VHF communication towers":
". . .such towers increase the incidence of lightning at the tower location
and the probability of lightning to a tower increases as the square of the
tower height."
Although the paper leaves many unanswered questions, and is primarily
intended to warn about the dangers of placing towers in close proximity to
people, this paper does seem to dispel some of the home-spun "theories"
about lightning and towers with respect to a tower's ability to dissipate
charges and thereby reduce the probability that the tower will take a
strike.
http://www.lightningstorm.com/resources/library/lightn1.pdf
Thanks,
Kevin.
------------------------------------------------------
Kevin Hemsley
Systems Engineer
Microserv Computer Technologies, Inc.
kev@ida.net
NF7J
----- Original Message -----
From: Jim Lux
To: Towertalk
Sent: Wednesday, July 07, 2004 8:01 AM
Subject: [TowerTalk] lightning frequency and towers
If someone were interested, you might be able to find someone at Vaisala
(who run the National Lightning Detection Network) who could take the
database of strike locations and match it up against the FCC antenna
database and see if there is any correlation (or lack).
The dataset extends back to the late 80's, and has locations within a few
hundred meters for each flash detected in most of the US
Try http://www.lightningstorm.com/
Folks with a research connection might be able to get free access to the
database through NASA/Goddard SFC or NWS.
http://www.lightningstorm.com/tux/jsp/guide/products/data/archive/index.jsp
Good summer project for a student.
_______________________________________________
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
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
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
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
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
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|