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Re: [TowerTalk] Antenna/Tower Grounding (Lightning Protection)

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Subject: Re: [TowerTalk] Antenna/Tower Grounding (Lightning Protection)
From: "Robert G. Strickland" <>
Date: Fri, 05 Jan 2007 04:07:49 +0000
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[I apologize if this is a dupe]

>Hello, all...

Being more of a beginner than an expert, and following this thread - and 
others - leaves me with questions "sort of" unanswered. Modeling lightning 
strike wave forms and calculating impulse energy/duration, while necessary, 
is still a bit removed from "okay, here's the tower, now what do I do?" I 
may be putting up a tower at a very high point that is <guaranteed> to take 
direct strikes. My kids across the road from my prospective QTH get 
<direct> hits on their wood fram house several times during the summer 
season. I've been at their house when it was hit [they have an extensive, 
somewhat traditional house grounding system], and for those unfamiliar with 
such an event, it is VERY impressive. Given direct hits, what's the plan? 
Discussions of big versus small strikes seems besides the point. A direct 
hit is BIG regardless of its relative size.

Disconnecting the equipment seems obvious. That done, is there a consensus 
on the following:

1. ground "everything" to the tower at the top and at the bottom.
2. top and bottom grounds should be single point, ie one large, thick 
copper plate.
3. top and bottom grounds and house ground [see #8] should consists of 
something like PolyPhaser and Ice equipment.
4. for very long runs of both coax and control cables, intermediate 
grounding is "recommended."
5. the bottom ground/single point should itself be attached to an 
"adequate" ground system at the lowest point possible [see #7 below].
6. the tower should be grounded independent of any RF radial system [tower 
may be up before radial system is installed].
7. each leg of the tower should be grounded via a VERY LARGE cable/braid to 
a series [2-5x] deep ground rounds driven down 6-10ft deep, stretched out 
along a run of around 10-20ft.
8. where the lines enter the house, another single point ground panel is 
installed that itself is grounded by at least one deeply driven ground rod.
9. any and all other house electrical and telephone line grounding should 
also be installed and connected to the single point ground in #8.

This approach may/may not correspond to any/all applicable codes. However, 
when the strike comes, believe me, nuances of code are lost in the BANG. 
What one wants is the biggest and most extensive of everything. This last 
statement is not meant to contradict the common sense expressed earlier in 
the thread that spending more on protection than the equipment is worth is 
not cost effective.

Also, carry insurance regardless of the grounding system [Murphy's Law].


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Robert G. Strickland PhD ABPH - KE2WY
Syracuse, New York  USA


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