I trust that these grounds are also connected or bonded back to the AC mains
ground. They should be according to NEC. This is one significant step that
I find most hams omit.
73
Bob, K4TAX
----- Original Message -----
From: "Merschrod" <kris@merschrod.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Friday, May 04, 2012 2:16 AM
Subject: [TenTec] Grounding out! (new title old thread :>)
For what it is worth, one of my better protections consists of three
ground rods about 15 feet apart that have the heavy multi-strand main
service type copper ground wire clamped (with no-Ox and wrapped with
sealer) between them and clamped to the tower. Then from there, for about
40 feet, is a run of the same ground wire to another ground rod at the
base of the drop line from my main multi-band (cats whisker)where there is
also an antenna switching box. That box and the coax connectors are
connected to that ground system too. When I leave for vacation or when
there may be storms, the drop lines go to ground and the switch and
underground coax line from there to the house is disconnected.
What are the odds? I do not know, but each step reduces them. Once I was
working in the Chapare Valley of Bolivia. It reminded me of Florida
friends' description of lightening. All dipoles were on towers that had a
lightening rod on top and grounding rods - the works. But if you really
like grounding and lightening stories, the best and most sophisticated
that I have seen is at the Arecibo Observatory in Puerto Rico. That
platform in the air is always at some sort of a "potential" and the guys
who work on it and prepare it for hurricanes say that when they are up
there on that steel platform, their hair starts to stand on end as storms
close in. Lightening is always hitting it and they have cables going
right to ground consisting of salt soaked pits to drain off that "static."
It is hard to imagine the EMF inducted to sensitive micro processors and
servos used to stabilize that platform at the base of those heavy cables,
but they are insulated well enough so that they seldom are knocked out,
but when they are knocked out the chore is to zip out there and into the
area under the dish and replace them so that the radio telescope is stable
and focused.
If you have a chance to go to the Observatory, contact the hams beforehand
who work there and ask for a special tour. It makes our home chores on
static look easy :>) (I had the pleasure of working at the Observatory for
six months a few years ago - awesome and for a guy who is afraid of
hieghts going up there to check out conditions was a real test.)
For sure the commercial radio station folks on this net can describe how
they are connected even if there are lightening storms.
73,
Kris KM2KM
> Absolutely! Bob McGraw is right about doing all your surge protection
> and lightning diversion outside the shack so as to not have a conductor
> path inside during a fault.
>
> In fact, when you are not home, you should unplug feedlines and
> preferably ground them if you have outside antennas in the clear.
> Lightning can and does bypass higher objects sometimes and goes for the
> wires, or aluminum of antennas.
>
> Unplugging the feedlines and power lines when the shack is not manned
> removes the equipment from any potential direct path, and lessens
> chances of losing all rigs and accessories to lightning. Don't overlook
> other electronics on the operating desk like computers and phones.
> Anything that has a connection outside the shack to utilities could
> bring lightning events inside. Don't be complacent if you have
> underground utilities. Somewhere out there, that utility line goes
> above ground and goes high up on a pole.
>
> A surge arcing inside your shack is a nerve shattering happening.
> Been there heard that back in Novice days.
>
> -Stuart Rohre
> K5KVH
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>
Briançon, France
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