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[TowerTalk] Grounds

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Subject: [TowerTalk] Grounds
From: (Guy Olinger, K2AV)
Date: Thu, 17 Jun 1999 15:54:33 GMT
On Tue, 15 Jun 1999 03:53:42 -0400, wrote:

>==     ==      ==      ==      ==      ==      ==      ==      ==
>So much for the polyphasers, differentials and backwards-zaps, etc.
>Check out this reprint of an article that appeared in World Radio a few
>years ago.
>                 (Or,  'Here goes TDF  A G A I N')


(Yuk, yuk, sniggle, snort) Amen...

All the polyphaser aside (and yes, I know who wrote "backward-zap"),
and after all the delicate care I will take to minimize known and
understandable lightning risks, the question still remains whether I
or Mother Nature is ultimately going to win in a head-knocking contest
over whether my protection is better than her Ka-Zap.

My favorite illustration of Who Always Wins If She Wants To:

At a certain well done shack in upstate New York a while back, a ham
couple had set aside one of the larger rooms in the house for computer
and ham gear. The table was in the center of the room. When not in
use, all cables, plugs, connections were disconnected, coiled up and
on the table in the center of the room, isolated by at least five feet
of room air gap from anything metallic in the walls. At the time of
this eposide all was disconnected in the equipment room and coiled up
on the table, and the Lady of the House was walking up the hall toward
the door into the equipment room.

Lightning hit the phone pole out back, ignoring the fairly
well-grounded tower next to the house. The phone pole, lacking a
ground sufficient to dissipate the strike, decided to try dissipating
on the phone lines, including the drop over to the house, which it
vaporized into a plasma conduit.

When it got to the house, it still couldn't find any real dissipative
path, because the telco ground was wimpy. Getting grumpier by the
microsecond, it decided to jump to whereever and see if it could find
a better path. "Ahah," it said to itself...

It jumped from the phone socket over the five foot air gap to the
table, sparking up two computers, two transcievers, and misc other
stuff. Still finding no ground, it jumped to the 110 outlet on the far
side of the wall (didn't like the one next to the phone outlet). In
the process it made one of those fireballs, which rolled out into the
hall and singeing the walls as it went, chased Lady of the House down
the hall and out the door, before it jumped into an outlet at the end
of the hall.

True story. I still have a piece of charred S100 computer from them to
remind me who's ultimately in charge.

Even TDF's unopened cardboard-boxed rig would not have survived on the
table that day when Mother Nature again proved her point.

We just cut down on the odds. And we can keep from being collateral
damage when Mother Nature takes out the neighbor. But Mother N gonna
get *us* with her Ka-Zap if she REALLY wants to.

(For the techno-types who just HAVE to know how come the above story
was possible, they lived on top of a broad dome, and the soil up there
was rocky and shallow by normal standards, and a fairly poor ground
without burying a fortune in copper, which accounts for all the wimpy
utility grounds.)

73, Y'all

73, Guy
--. .-..

Guy Olinger, K2AV
Apex, NC, USA

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