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Re: [TowerTalk] Grounding of Amateur Radio installations

To: (Phil Camera),
Subject: Re: [TowerTalk] Grounding of Amateur Radio installations
From: Pete Smith <>
Date: Fri, 08 Dec 2006 10:08:51 -0500
List-post: <>
Actually, I took a direct hit on my 40M yagi some 3 years ago, about 200 feet 
from the house and 100 feet in the air.  Thanks to disconnection, I lost 
nothing on the radio side in the shack.  Unfortunately, my wired Ethernet 
network connections made a good antenna, and  the induced EMP killed both 
computers.  Aside from them, we lost only the stuff on the tower, and a 
telephone answering machine.  I'm not sure that additional measures would do 
much to improve on this.

73, Pete N4ZR

At 09:55 AM 12/8/2006, Phil Camera wrote:
>Even though a second floor shack is not optimum, installing a well designed 
>grounding system is not out of the realm of possibilities.  Polyphaser has a 
>good technical article discussing exactly this problem.
>In summary a well designed grounding system consists of the following elements:
>1.  Tower or mast ground
>2.  SPG
>3. Lightning arrestors
>4. Shack ground
>5.  Service entrance ground
>All five must be tied together, outside, for it all to work.  Leave out any 
>part, and Mother Nature has an entry route.  Yes, being upstairs from your SPG 
>is a problem but what you'd need to do is install the lowest 
>resistance/impedance ground from your shack to the rod.  The best would be 
>copper strip a number of inches wide.  With everything listed connected 
>together, when your system gets that energy surge from a strike or nearby 
>strike (up to a mile away can induce enough current to fry electronics) then 
>everything rises in voltage together and there is no potential difference 
>between grounds which is what zaps your electronics.
>Simple disconnetion outside can work, as far as eliminating the lightning 
>arrestor part of the above list but you'd then still need to take care of all 
>the other listed items.  A surge via your power lines can also zap your 
>electronics even if the coax is disconnected.  The best would be to totally 
>disconnect your rig and put it in the closet but I'd doubt you'd do it every 
>time and it only takes one time to get bummed out.   Worst case you might have 
>lightning getting into the house and that can be bad also.
>Phil  KB9CRY
>-------------- Original message -------------- 
>From: Pete Smith <> 
>> At 09:18 AM 12/8/2006, Phil Camera wrote: 
>> >"Something to bear in mind is that, in general, most jurisdictions don't 
>> >bother 
>> enforcing the NEC for amateur radio antennas" 
>> > 
>> > 
>> >Which actually is too bad because these guidelines are exactly the measures 
>> >one 
>> should do for a properly installed safety & lightning prevention grounding 
>> system. And every single measure must be in place or else you're leaving an 
>> entry route for Mother Nature to bite you. 
>> > 
>> >Phil KB9CRY 
>> Which is fine if your shack is in an optimal location so that you can do 
>> everything by the book, but what if it's on the second floor of an old 
>> house? I 
>> attempt a single-point ground in th e shack, but it is a long way from earth 
>> ground. I am not so naive as to believe I'm going to be able to survive a 
>> hit 
>> if the cables from my tower are connected. Is simple disconnection at the 
>> shack 
>> entrance up to code? I don't know, but it's all I have. 
>> 73, Pete N4ZR 


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