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Re: [TowerTalk] Single Point Grounding question

To: K1TTT <K1TTT@ARRL.NET>
Subject: Re: [TowerTalk] Single Point Grounding question
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Date: Fri, 04 Sep 2009 15:12:09 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>

K1TTT wrote:
>> I doubt it as the shield for the coax cables are grounded side by side
>> at the tower and at the bulkhead where they enter the house.  The two
>> leads that arced over are about 8' long and are just a continuation of
>> those same coax cables.
>>     
>
> It is possible it was just induced voltage also, a nearby stroke can induce
>   
Nearby it was. <:-)) It was a direct hit on the tower which likely had a 
number of secondary hits around the area. So there was most likely 
induced as well as direct currents flowing.
> quite a high voltage in an open loop.  That it would have enough energy to
> be that loud is odd, but maybe there were a combination of nearby arcs that
> made a bigger noise than just that one gap.
>   
Basically every thing was hooked up, radios, computers, networks, and 
TV. Both the shop and house systems were running with two CAT6 hardwired 
computers in the shop and two in the house tied into an 8 port switch 
plus router. Actually the duo-band 144/440 rig was hooked to the Alpha 
Delta switch. It was still running after the flashing lights and noise. 
As I mentioned in another post the Polyphasers in the UHF and VHF coax 
(the ones affected) survived just fine.

The flash and bang reminded me of a disconnected and ungrounded cable to 
an ungrounded antenna which is a very good reason for NOT disconnecting 
the coax from the rigs when a storm is coming unless you throw the coax 
outside, or better yet, hook it to an outside grounding plate. An 
ungrounded and disconnected coax in the house is *dangerous*  BTW the 
144 and 440 arrays are on a cross boom at 130' which is the highest 
point on the tower, or rather 30' above the top of the tower.

73

Roger (K8RI)
> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>  
>
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