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Old November 30th 03, 05:52 PM
w_tom
 
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Clifton's posts without technical details. Common among
naysayers, who know but cannot even be bothered to learn the
numbers, is this classic example of technical naivety:
You can't produce a protection device that will not sacrifice
itself given a direct lightning strike, not even a 10"
diameter solid steel rod.


Yes, Clifton would have us believe that lightning could
vaporize a 10" diameter steel rod. He did not even post how
many amps must be in a lightning strike to vaporize that 10
inch diameter steel rod!

Instead we learn from industry professionals:
http://www.harvardrepeater.org/news/lightning.html
Well I assert, from personal and broadcast experience spanning 30
years, that you can design a system that will handle *direct
lightning strikes* on a routine basis. It takes some planning
and careful layout, but it's not hard, nor is it overly
expensive. At WXIA-TV, my other job, we take direct lightning
strikes nearly every time there's a thunderstorm. Our downtime
from such strikes is almost non-existant. The last time we went
down from a strike, it was due to a strike on the power
company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning vigorously
to educate amateurs that you *can* avoid damage from direct
strikes. The belief that there's no protection from direct
strike damage is *myth*. ...
The keys to effective lightning protection are surprisingly
simple, and surprisingly less than obvious. Of course you
*must* have a single point ground system that eliminates all
ground loops. And you must present a low *impedance* path for
the energy to go. That's most generally a low *inductance*
path rather than just a low ohm DC path.


Only the naive would believe one needs $thousands to install
an earthing system. And yet that is what Clifton would have
us believe.

If a surge protector fails, then it was clearly undersized
for the task. Surge protectors should be so effective that
one never knows it did its job - in direct contradiction to
what Clifton posts. The most critical component in surge
protection is earthing. Direct lightning strike without
damage is routine. Clifton would even deny this. A surge
protector is only as effective as its earth ground. No earth
ground means no effective surge protection. Clifton has some
wild idea that sacrificial MOVs will provide the protection -
which is why he insults rather than post a single technical
number. Instead Clifton would have us believe that lightning
would vaporize a 10 inch diameter steel rod - without even a
single numerical fact.

"Clifton T. Sharp Jr." wrote:
...
w_tom wrote:
In the radio industry, properly earthed surge
protector are so well appreciated that these industry
benchmark application notes are considered legendary.


The radio industry can afford hundred-thousand-dollar Ufer grounds
and ten-thousand-dollar lightning shunts. And radio stations STILL
go down in storms from lightning strikes.

Do they discuss their product line? Of course not. They discuss
the most important feature in any surge protection system -
earthing:
http://www.polyphaser.com/ppc_pen_home.asp

A surge protector being only as effective as its earth
ground.


The radio industry can afford hundred-thousand-dollar Ufer grounds and
ten-thousand-dollar lightning shunts. And radio stations STILL go down
in storms from lightning strikes.