[TowerTalk] grounding elevated vertical for lightning?

[Jim Brown]

There are two elements to the protection. First, the coax shield is 
bonded to the panel and from there to the rest of the ground system. 
Second, the gas tube shorts the center conductor to the shield, which 
limits the voltage at the equipment input.

73, Jim K9YC

On 2/10/2013 7:49 AM, David Jordan wrote:
> Jim,
>
> Isn't part of the Polyphaser lightning protection circuit a spartgap? 
> I opened one up and thought I saw a gas tube.
>
> 73,
> Dave
> wa3gin
> ----- Original Message ----- From: "Jim Brown" 
> <jim at audiosystemsgroup.com>
> To: <towertalk at contesting.com>
> Sent: Sunday, February 10, 2013 1:52 AM
> Subject: Re: [TowerTalk] grounding elevated vertical for lightning?
>
>
>> On 2/9/2013 12:43 PM, Mark Robinson wrote:
>>> Could he not also ground through an rf choke to bleed off static?
>>
>> Lighting is NOT a DC event, it is an RF event.  Chokes block it 
>> (until they fry).  Not a solution.  As AC0C noted, the coax is 
>> grounded at the house/shack, as it must be, which provides a DC path 
>> anyway.
>>
>> As W8JI has observed with respect to several other problems of this 
>> nature, we must consider the entire system.  The length of the coax 
>> matters a lot -- a long run of coax has a lot of inductance, so it's 
>> close to an open circuit for lightning.
>>
>> Jim Lux got it right -- a spark gap to a local rod does the job for 
>> lightning and doesn't degrade the antenna system.
>>
>> 73, Jim K9YC
>> _______________________________________________
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>>
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>