Re: Railroad counterpoise

On Mon, 15 Jul 1996 22:25:10 -0600, Tesla List
<tesla-at-poodle.pupman-dot-com>, you wrote:

>> Subject: Re: Railroad counterpoise
>>From hullr-at-whitlock-dot-comMon Jul 15 22:23:40 1996
>Date: Mon, 15 Jul 1996 09:20:13 -0700
>From: Richard Hull <hullr-at-whitlock-dot-com>
>  When he ran a small coil, the system did just 
>fantastic.  The plate acted as an effective ground and counterpoise.  
>When he connected a beefy coil's resonator base onto the plate and ran at 
>a KW or two the plate started issuing sparks too.
>This is why Tesla got sparks off of water mains and his arrestors arced 
>over in Colorado.  He had such a powerful system and the ground was so 
>dry, he was able to power up the local ground, showing that he had 
>defeated his counterpoise.  He spent a number of days mproving his ground 
I found a great page on grounding last night in search of my elusive
neutron page. This page is from a company that specializes in
grounding systems for radio towers. In the second snippet, they talk
about using concrete as  part of a ground system.




------------------ snip of www page ---------------------------
CHAPTER ONE - Current Distribution

     Much has been written on the techniques of Lightning Protection.
Indeed, there is much to know about the art of proper grounding that
encompasses the laws of physics and RF design. We hope you will follow
these proven concepts which will protect your valuable equipment from
even direct lightning hits. Whether your equipment is a radio site,
pipe line, utility substa-tion, telephone central office, tactical
military, ship-board, or security installation, the same requirements
apply for proper protection, installation and grounding.


     Lightning takes the form of a pulse which typically has about a
2us rise and a 10 to 45us decay to a 50% level. Presently, the IEEE
Standard is an 8 by 20us wave-form. The peak current will average 18kA
for the first impulse (stroke) and less (about half) for the second
and third impulses. Three strokes is the average per lightning strike.
A strike is a constant current source. Once ionization occurs, the air
becomes a conductive plasma reaching 60,000 degrees F and is luminous.
This luminosity level is brighter than the surface of the sun! The
resistance of a struck object is of small consequence, except for the
power dissipation on that object (I2 x R). Fifty percent of all
strikes will have a first strike of at least 18kA, ten percent will
exceed a 65kA level and only one percent will have over 140kA. The
largest strike ever recorded was almost 400kA.
---------------------end snip----------------------------------

------------------ snip of www page ---------------------------

Concrete is a fair conductor and can be used safely and effectively to
augment your tower grounding system. The characteristic which makes
this practical is the concrete's ability to quickly absorb moisture
and release it slowly over a long period of time. The pH of the
released moisture in turn enhances the conductivity of the surrounding

It is a common misconception to think that a lightning strike will
blow up a concrete pad.  However, consider first, a myth-perpetuating
case of an improperly designed system where the tower leg "J"-bolts
are imbedded directly into the concrete pad. In this case, due to the
poor nature of the tower ground system, each of these J-bolts will
actually share a significant amount of strike current which in turn
will flow through the concrete.

---------------------end snip-----------------------------------------