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Re: [TowerTalk] Conductive Concrete and Grounding

To: "K8RI on Tower Talk" <>,"Charlie" <>, "Bill Shell" <>,"Tower Talk List" <>
Subject: Re: [TowerTalk] Conductive Concrete and Grounding
From: "Jim Lux" <>
Date: Wed, 26 Jan 2005 22:14:06 -0800
List-post: <>
----- Original Message -----
From: "K8RI on Tower Talk" <>
To: "Charlie" <>; "Bill Shell" <>; "Tower
Talk List" <>
Sent: Wednesday, January 26, 2005 6:40 PM
Subject: Re: [TowerTalk] Conductive Concrete and Grounding

> The one thing predictable about lightning is its unpredictability.
> The Science (Discovery) channel had an interesting program on this a
> of weeks back.

While the producers of shows on Discovery Channel usually(!) try to be
technically accurate, one should remember that they are being paid to

> Supposedly the regular strikes of a strength that can be managed, while
> super strikes are a tad beyond our abilities at present.

The statistics of lightning have been measured for years... The vast
majority are the usual 10-20 kA kinds of things, but there are occasional
100+kA strokes.  The very large strokes also have large "continuing
currents", which causes a lot of ohmic heating, so they do a lot of damage.

> So, taking precautions should mitigate damage from the lesser strikes, but
> with the super strikes you can only hope for the best.

It's all a statistical gamble in any case.  Two things to keep in mind:
How much are you willing to pay?
How much can you tolerate losing? (and how often)

Answer those two questions, and most equipment, insurance, etc. issues can
be resolved.

If you live in a lightning prone area, maybe a bigger investment in
lightning protection is worthwhile. Or, maybe, investing that same dollars
in an insurance policy is a better deal (if you can tolerate the down time
while waiting for new equipment).

I suspect that most hams are in a very different situation from a commercial
provider. Commercial providers have implied or explicit "maximum downtime"
requirements.  Hams generally don't.


See:  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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