To: <towertalk@contesting.com>
>Date: Tue, 29 Oct 1996 22:49:10
>To: K8DO@aol.com
>From: "Roger L. Elowitz" <K2JAS@worldnet.att.net>
>Subject: Re: Ground Rod Placement
>
>Hi Denny,
>
>I've been getting many replies on this thread. Yours is more specific than
most and very much appreciated. I'm summarizing at the end.
>
>You mention using a large diameter conductor for the grounding cable run. I
managed to acquire some vinyl jacketed STRANDED copper cable whose diameter
(on closer inspection) appears to be equal to the diameter of my pinky finger.
>
>Some people seem to be adverse to using stranded cable for this application
without explaining why. You are the first to mention using aluminum flashing
or siding. That I find most interesting and ingenious. However, wouldn't
that stuff simply vaporize in a real lightning strike? And for that matter
so would my pinky diameter copper cable- wouldn't it? And, at the voltages
likely to be encountered in a lightning strike, what's a few millihenries
more or less inductance going to mean? (asked in all seriousness)!
>
>At 10:48 PM 10/29/96 +0000, you wrote:
>>2 foot should do it... but then, I would put out a spread of 2 or more ground
>>rods, spaced 16 feet apart, and running heavy, bare wire from rod to rod...
>>even 1 extra rod will help tremendously... if you don't have enough of a yard
>>for a spread of rods, then run them around the perimeter of the house...
>>studies show that a ground rod will drain excess charge (in average ground)
>>for a radius of (roughly) 8 foot... putting the rods too much closer than 16
>>foot apart overlaps their influence area,... conversely, much more than 16
>>foot will allow a significant charge to build between rods... in dry, sandy
>>soil you might close them in about 25%, and in wet, highly organic soil,
>>spread them out 25%...
>>
>>In general a large diameter conductor is better than a smaller diameter... a
>>flat ribbon, 2" or 3" wide cut from aluminum roofing flashing (copper would
>>be great, but expensive) will have lower inductance and be even better... a
>>parallel run of smaller conductors will also lower the inductance per foot,
>>compared to a single larger conductor...
>>
>>Denny
>>
>
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