Topband: Earth conductivity

[Richard (Rick) Karlquist]

Gary Hinson wrote:

> Talking of that, any idea how conductive my soil might be?  It's about 12" of topsoil on a clay
> base, the depth of which exceeds any holes I have yet dug.  It's the sort of solid Real Man's Clay I
> could probably lever out with a spade, leave to dry in the sun, and build a house from.  If they's
> have asked me, I'd have offered to make the heat-refractive tiles for the space shuttle from it.
> 
> I know I really ought to measure it, and I have the design somewhere hereabouts for the gizmo to
> measure ground conductivity which I *will* build one day.  And I may be lucky enough to find
> geological maps of this area at some point to find out what lurks beneath.  But for now, what do you
> say: is topsoil-over-clay high, medium or low conductivity in the grand scheme of things?  
> 
> And, given that, what are the implications?   
> 
> I have ~20 acres of the stuff, with access to hundreds more in the pine forest surrounding our

> Gary  ZL2iFB

Sounds exactly like my 20 acres.  We tried to rip it up with a 7 foot
plow and it stalled a 100 ton, 600HP CAT D-10.  My clay goes down 30 
feet before hitting sand.  My land is shown as near 30 mS on the FCC
conductivity map.  Verticals work extremely well, beverages don't. 
Instead of some abstract ground conductivity measurement, just put up a 
beverage and see how fast the current is attenuated by using a clamp-on
current probe.  On my land, I'm done after 400 ft.  Any additional wire
is wasted.  I still get a lot of use out of my short beverages, but
I don't think they play as well as the really long ones over sand.

Rick N6RK