On Sailboats a porcupine is only intended to disperse the static that builds
on the vessel during a thunderstorm. They have not been proven to work that
well, and you won't see very many sailing yachts with one on the main mast.
Ground systems are no guarantee that you will not get a strike either. My
ground system is on par with a commercial broadcast station and yet I drove
home one day to see pieces of a 6 element 20 meter mono-bander and the rotor
all over the field following a severe thunderstorm. We have had worse
storms where I've watched lightning hit the towers and sustained no damage,
but this hit beat them all I guess. The hard-line, rotor cable,
polypahsers, and so on were all cooked. It even got 4 strain insulators on
the guys. There's roughly 4 miles on 10 gauge solid copper in the ground
and 60 12' ground rods all interlinked and tied to the commercial ground per
engineering designs. We get a lot of t-storms and lightning strikes at our
QTH, so I went the extra mile and still had an insurance claim.
Just goes to show that no matter how prepared you are you can still get a
big strike!
By all means don't even touch a wire or gear during a storm. I've had sparks
fly between my fingers when I walked by an 40 meter yagi antenna I was
building in my shop/shack during a major storm...ended up crouching on the
floor with the hair standing up on my head as one of the towers took a hit.
That one was so bad that my family was in the center of the house 100 yards
away doing the same thing I was and praying for me since I was so close to
the major action.
Shoot, our horse barn is even tied into the ground system since it's close
to one of the towers.
Build to take the heat, but it still may not take all of it. I'd venture
that I have some $7k in my ground system.
Cam Hedrick
WA4JKW
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of
towertalk-request@contesting.com
Sent: Tuesday, July 04, 2006 12:01 PM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 43, Issue 13
Send TowerTalk mailing list submissions to
towertalk@contesting.com
To subscribe or unsubscribe via the World Wide Web, visit
http://lists.contesting.com/mailman/listinfo/towertalk
or, via email, send a message with subject or body 'help' to
towertalk-request@contesting.com
You can reach the person managing the list at
towertalk-owner@contesting.com
When replying, please edit your Subject line so it is more specific
than "Re: Contents of TowerTalk digest..."
Today's Topics:
1. Re: Grounding base slab and pier tower bases (Keith Dutson)
2. Re: Water tower omni (bthorson@4smps.com)
3. Re: Grounding base slab and pier tower bases (David Robbins K1TTT)
----------------------------------------------------------------------
Message: 1
Date: Tue, 4 Jul 2006 10:24:32 -0500
From: "Keith Dutson" <kdutson@sbcglobal.net>
Subject: Re: [TowerTalk] Grounding base slab and pier tower bases
To: "'Doug Renwick'" <ve5ra@sasktel.net>, <towertalk@contesting.com>
Message-ID: <001e01c69f7d$f359b9f0$7401a8c0@DUTSON.CORP>
Content-Type: text/plain; charset="us-ascii"
No need to present facts available to you. Just look up measured energy of
a strike and compare it to the ability of the porcupine to dissipate this
energy. BTW, while you are looking for facts, try to determine the amount
of charge that can be dissipated by the porcupine.
73, Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Doug Renwick
Sent: Tuesday, July 04, 2006 9:57 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Grounding base slab and pier tower bases
I did not say that porcupines will stop all lightning strikes.
I said "In other words, my addition of the porcupine did not have a negative
effect."
Scientific experiment will only trump experience IF the scientific
experiment can exacting duplicate the experience and conditions!
Please present your scientific experiment that proves porcupines will not
stop strikes, any strike.
Doug
Subject: Re: [TowerTalk] Grounding base slab and pier tower bases
Experience may trump theory, but scientific experiment trumps experience
EVERY time! porcupines on towers have been shown to not stop strikes. Not
any more than an owl stops birds.
David Robbins K1TTT
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.394 / Virus Database: 268.9.8/380 - Release
Date: 6/30/2006
------------------------------
Message: 2
Date: Tue, 04 Jul 2006 11:33:25 -0400
From: bthorson@4smps.com
Subject: Re: [TowerTalk] Water tower omni
To: towertalk@contesting.com
Message-ID: <44AA8A45.6070809@4smps.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Can you tell me more about the 'Rolling Ball' concept and lightning?
I've never heard of it.
Someone, I think it was in the forum, said that lightning protection is
like an insurance policy. The more you spend, the better your
protection, but you couldn't guarantee that you weren't going to get
taken out. Of course, there's the people who say that's silly, that
professional broadcasters have to stay on all the time, through
lightning hits etc. Of course their equipment is a bit heavier and a lot
more expensive the typical equipment I install.
The side tank mounting has been, at least so far, a relatively safe
method. I think we've had one side tank mounted antenna taken out at
most. (Actually the antenna wasn't taken out, but the coax as it was an
old installation that wasn't properly grounded, if I remember correctly.)
Ben
------------------------------
Message: 3
Date: Tue, 4 Jul 2006 15:55:38 -0000
From: "David Robbins K1TTT" <k1ttt@arrl.net>
Subject: Re: [TowerTalk] Grounding base slab and pier tower bases
To: <towertalk@contesting.com>
Message-ID: <003a01c69f82$4b885ab0$0800a8c0@k1tttibm>
Content-Type: text/plain; charset="us-ascii"
http://lists.contesting.com/_towertalk/2004-03/msg00380.html
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Doug Renwick
> Sent: Tuesday, July 04, 2006 14:57
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Grounding base slab and pier tower bases
>
> I did not say that porcupines will stop all lightning
> strikes.
> I said "In other words, my addition of the porcupine
> did not have a negative effect."
> Scientific experiment will only trump experience IF the
> scientific experiment can exacting duplicate the experience
> and conditions!
> Please present your scientific experiment that proves
> porcupines will not stop strikes, any strike.
>
> Doug
>
> Subject: Re: [TowerTalk] Grounding base slab and pier tower
> bases
>
> Experience may trump theory, but scientific experiment
> trumps experience
> EVERY time! porcupines on towers have been shown to not
> stop strikes. Not
> any more than an owl stops birds.
>
>
> David Robbins K1TTT
>
>
> --
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.9.8/380 - Release
> Date: 6/30/2006
>
------------------------------
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
End of TowerTalk Digest, Vol 43, Issue 13
*****************************************
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|