Re: [TowerTalk] [Bulk] Re: [Bulk] Re: copper or galvanized ground rods in red SC clay

[jimlux <jimlux@earthlink.net>]

On 1/10/16 11:40 AM, David Robbins wrote:
> At lightning current densities and time scales the earth ionizes and rapidly
> increases its conductivity.  See equations by Weck and others:
> http://www.ipstconf.org/papers/Proc_IPST2011/11IPST109.pdf
>
> Note in the graphs how the effective resistance of the ground decreases as
> the current increases.
Very interesting..
(and, of course, there's about a 3:1 difference among the various 
models, which I'd sort of expect)
That paper and the references it cites will give me a fair amount of 
reading.
However, I don't see any sort of "saturation" behavior: in fact, it's 
more of a negative resistance (i.e. resistance goes down as current goes 
up).

> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> jimlux
> Sent: Sunday, January 10, 2016 17:42
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] [Bulk] Re: [Bulk] Re: copper or galvanized ground
> rods in red SC clay
>
> On 1/10/16 8:56 AM, Roger D Johnson wrote:
> > Another factor not usually considered by hams is that conduction
> > through the ground is NOT the same as conduction through a copper
> > wire! A copper wire has a copious supply of free electrons and will
> > happily conduct increasing amounts of current until it melts. In soil,
> > the conduction is by ions from metallic salts in the earth. The supply
> > of ions is finite and when all are being used to conduct electric
> > charges, the resistance rises sharply. The soil has gone into
> > "saturation".
> do you have a reference for this?  I'm interested in a more technical
> description of the phenomenon.
>
> I'm familiar with some other soil and tissue conductivity phenomena relevant
> to RF having to do with the ion mobility (e.g. the Cole-Cole model which is
> used for all sorts of things at all sorts of frequencies:
> prospecting for ore, measuring the ripeness of produce, and RF imagery of
> human bodies)
>
>
>    A lightning ground system
> > has to be designed to dump the current from a strike into a large
> > "volume" of earth capable of conducting the strike current.
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk