I use them, have for over 20 years ...how effect are they I don't know,
BUT when the clouds are low, very dark and you can taste the ozone, and
the hair on your arms stands up...the porcupines put on a show similar
to kids with the 4th of July sparklers...all my towers are between 80
and 140 feet, as to the effect on lower towers, BUT also the towers are
grounds with multi rods in open face feeding pits, ...a quarterly dose
of gypsum and Rock salt ....again as to the effect and protection, I do
not know, but the home 200 meters away was hit and blew an 8 foot hole
in the roof, another house 1000 meter away was hit and burned ...
Also on the typical Ham towers I have SS jumpers across each joint to
enhance the conductivity.
See some of it..
http://www.kc4pe.com/amateurshack.htm
-Bill .... KC4PE
On 8/8/2015 12:19 PM, Patrick Greenlee wrote:
My quick literature search showed the US Navy and others tested the
ESD (Electrostatic Dissipation devices AKA porcupines) and found them
to not reduce the frequency or number of lightning strikes on their
test structures.
Seems counter-intuitive to me but I can't argue with their results as
I have no experimental results to the contrary. From what I read the
porcupines can't handle the currents required to prevent the charge
building up and having a strike.
I'm sure folks in the business of selling protective devices put the
best face on their product as possible but...
In my early years I was taught that lightning rods were to prevent a
strike by draining off the charge preventing a build up sufficient to
make for a strike and to be well grounded with low resistance-low
inductance paths to ground in case they took a strike. Oh well,
empiricism trumps theory and or wishful thinking.
Patrick NJ5G
On 8/7/2015 10:12 PM, Jim Lux wrote:
On 8/7/15 7:39 PM, Tony wrote:
All:
I came across this video from Nott Ltd that describes how their static
discharge arrays or "Porcupines" help disapate static electricity to
prevent lightning strikes.
https://www.youtube.com/watch?v=JYILAHIx2lk
I understand they are used in several industries including
communications towers and was wondering if anyone has experience with
them. Installation is easy enough, but I wonder how this work work with
crank-ups?
Totally ineffective.
You're not going to "dissipate" the charge in a thunderstorm.
http://lists.contesting.com/_towertalk/2004-07/msg00971.html has a
discussion. Run back and forth in the thread for more discussion.
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