[TowerTalk] Static, Lightning, and protection

[W0UN -- John Brosnahan]

The often repeated personal experiences of K0RF, W4ZV (then
known as W0ZV), and myself is that lots of grounded elements
on a tower greatly reduces the number of lightning strokes.  We
have all observed a storm cell moving towards us that was
generating lots of strikes.  As the cell neared our towers the
lightning stopped and the guy wires started crackling and popping.
As the cell passed on by the lightning would resume.  CLEARLY
the towers were doing something to reduce the incidence of
strikes in the immediate vicinity. Whether the little "do-hickeys"
at the top of the tower are helpful or not is another issue.  The
spikes occupy a pretty small volume of air compared to a number
of stacked HF antennas with grounded elements.

The two best mapped areas for lightning distribution are
Florida because of the Kennedy Space Center and Colorado
because of the confluence of NOAA and the National Center
for Atmospheric Research.

 From personal experience there is a lot of lightning in CO,
but the intensity is somewhat less since the ground elevation
is at 5,000 ft so the storms have 5,000 ft less elevation to
develop their charge.

Here are some links to the three main groups of which I
am aware doing lightning research.  Should be enough
to get anyone who is seriously interested in lightning
started with their reading.

The Florida and New Mexico groups do a lot with trailing
wire rockets as well as many other experiments.  Krider
does a lot of electric charge distribution inside the clouds
as well as current distribution in the ground beneath the clouds.

--John   W0UN


William Winn at Langmuir Lab at New Mexico Tech, Socorro, NM
http://bat.nmt.edu/
http://www.ee.nmt.edu/~langmuir/
http://ibis.nmt.edu/nmt_lms/

Paul Krider University of Arizona, Tucson
http://www.atmo.arizona.edu/personalpages/krider.html
http://www.atmo.arizona.edu/

Martin Uman at the University of Florida, Gainsville
http://www.uman.ece.ufl.edu/
http://www.lightning.ece.ufl.edu/
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