I think porcupines fall into that category of 'if you tell a lie frequently
enough, eventually you believe it, too.'
Which might explain a lot of the opposition to Ufer grounds...
73, Kelly, ve4xt
Sent from my iPad
> On Aug 8, 2015, at 11:34 AM, David Robbins <k1ttt@arrl.net> wrote:
>
> The purpose of franklin style lightning rods is to provide a preferred point
> for the stroke to attach and then provide an easy path to ground for the
> current. There is nothing you can do to 'drain' the charge away since it is
> being attracted straight out of the earth by the charge built up at the
> bottom of the thundercloud. The best you can do is provide the sharp point
> to initiate a streamer to connect to the downward moving leader and then
> keep that current out of your building.
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Patrick Greenlee
> Sent: Saturday, August 08, 2015 16:19
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Static Discharge Porcupines?
>
> 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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