[TowerTalk] RE: TowerTalk Digest, Vol 19, Issue 122

[Dudley Chapman]

Yes, that concerns me, too.  The distance between the two entry points will
surely produce a difference in potential on one utility ground vs the other
if one utility gets hit.  And when they combine at a rig, there will be
problems.  

Although his proposed grounding scheme will improve the situation greatly, I
wonder if it might be better to run the phone line underground to the other
side of the house and have it enter beside the electrical utility, with
their grounds bonded together.  It would not be less work than running the
ground system around the house underground.

Dudley - WA1X



Date: Thu, 29 Jul 2004 14:57:48 -0500
From: "Jim Brown" <jim at audiosystemsgroup.com>
Subject: RE: [TowerTalk] Grounding, Lightning & corona discharge
To: "Tower Talk List" <towertalk at contesting.com>
Message-ID: <20040729195800.9FA4D7D42 at gw1.nlenet.net>
Content-Type: text/plain; charset="us-ascii"

On Thu, 29 Jul 2004 11:16:08 -0500, Keith Dutson wrote:

>I want to see less than .01 ohm resistance across the longest path. 

When thinking about it, remember that the energy in lightning is NOT at 
dc, it is around 1 MHz. The impedance of that path is primarily 
INDUCTIVE REACTANCE, not resistance. Resistance (greatly 
increased by  skin effect)  will certainly produce the I2R losses, but XL 
will determine current! 

Jim Brown  K9YC

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