On Thu, 2 Sep 2004 15:10:33 -0500, (Richard
Harrison) wrote:
Coastal Texas is almost as good as it gets when it comes to soil on the
map, 30 millimhos per meter. Seawater is not shown on the map but its
conductivity is given as 5,000 millimhos per meter or 167 times as good
as the best soil.

Hi Richard,

If all would review the standard FCC groundwave propagation curves,
they would notice that they offer low AM Band signal strengths in
terms of "conductivity" and that the differences in strength for the
5,000 millimhos per meter and that of 40 millimhos per meter (125 fold
difference) DO NOT achieve the same proportional difference in
received signal strength. In fact, the difference is so narrow you
could shave with a razor as sharp as it. Even at the high end of the
band the difference has to be out 700 miles to show the "conductive"
ratio. Of course, over that range of transmission ONLY Sea Water
would support that forecast as continental soil varies vastly in
smaller spans - hence the reputation of the Sea.

John Cunningham says in "The Complete Broadcast Antenna Handbook: on
page 309 that:
"The conductivity of the earth ranges from about 2 millimhos per meter
for dry sandy locations to as high as 5 mhos/m for sea water."

This is the conundrum of conductivity of earth: that there is so much
contradiction. You cite coastal Texas, but in distinct contradiction
to the dry sandy locations forecasts, pan handle Texas also exhibits
just as high conductivities for less water as Corpus Christi which
oddly enough easily has twice the sand content as those arid
wastelands.

There are a lot of reductionist statements about ground that simply
don't exhibit against the claims made for it. Reggie has long claimed
to be an authority on the subject, and when push comes to shove for my
hints that he offer Kelvinian substance, he complains about the CIA or
his insufficient understanding of English. The urchins of Rio would
guffaw at that one. I will anticipate Punchinello's Magic 8-Ball
answer "try again later," as I am sure the software could do no
better. ;-)

And by the way, the kitchen calibration of mud is a common gardener's
exercise, why Punchinello cannot or does not recite it is evidence
that no one really cares to ask (me or him). His embarrassment would
be found in its lack of correlation to RF (there are far more
variables to consider).

73's
Richard Clark, KB7QHC