[Top] [All Lists]

Re: [TowerTalk] Lightning

To: Doug Renwick <>,,
Subject: Re: [TowerTalk] Lightning
From: Jim Lux <>
Date: Fri, 05 Jan 2007 20:27:05 -0800
List-post: <>
At 05:30 PM 1/5/2007, Doug Renwick wrote:
>So far nobody, NOBODY, has presented sound empirical data
>that proves the porcupine does or does not reduce the
>incidence of lightning strikes.

Aside from the problems inherent in "proving a negative", there IS 
published engineering testing that shows no statistically significant 
benefit AND there's a fair amount of theoretical physics that says 
they provide no benefit.

As the saying goes: "Extraordinary claims require extraordinary proof"

>  Without that data, you are
>nothing more than an opinion.
>At the bottom read the post from WD4K.

But nowhere does WD4K say anything about spending money on something 
that has no benefit.  Sure, there's always a cost benefit tradeoff on 
all lightning protection.  And, contrary to the guy from Polyphaser's 
statement, you CAN design and build a system that tolerates ALL 
strikes.  For instance, the antennas on top of the Empire state 
building received so many direct hits that they provided a lot of the 
statistical lightning stroke data used for designining protection 
systems.  The LLL study talks about how to design an explosives 
storage area to take worst case lightning or EMP (which is actually a 
tougher problem).

I've got an open mind.  If a lightning eliminator/static dissipator 
manufacturer (or anyone else, for that matter) wants to do a 
rigorously controlled study and publish the results, I'm willing to 
change my opinion.  But, if they're going to rely on "we installed it 
in one place and we didn't get hit (as much) by lightning" that's not 
real convincing.  And if the mfr is going to play the "as sold to 
NASA" game to imply an endorsement, that's really lame.  The problem 
is that everybody who has actually gone out and done real tests with 
decent experimental processes has found no statistically significant 
effect.  This is basic junior high scientific method stuff: running a 
control group, swapping devices between towers, etc.

And, of course, for lightning protection in general, it's quite the 
crap shoot, and, in the great middle ground between absolutely 
nothing and the nuclear trigger explosives vault bombproof shelter, a 
lot of what you do is "judgement calls". i doubt many hams would go 
to the trouble to actually do a cost/benefit analysis on all parts of 
the system, carefully trading off incremental protection against 
expected loss over time. You do what seems ok and go from there.  If 
the porcupine makes you think it's safer and you can sleep better at 
night, it's worth it.

Jim, W6RMK  


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>