ground with kitten litter
By Guy Atkins
hcdx list, August 10, 2000
Bentonite is great for getting an excellent conductive ground.
That's the stuff used in clumping kitty litters.
I had forgotten that the "clumping" litters are Bentonite. The brand
we buy for our Siamese cat says that it's "a natural clay product...".
That's the Bentonite!
If you can locate a supply of the mineral called Bentonite,
it makes an excellent ion-rich (and non-corrosive) backfill for
ground rods and grounding systems. Professional antenna installations
and electrical substations use Bentonite for lowering the resistance
I have read that Bentonite is sold at animal feed stores; it is
used as an additive to cattle & pig feed. Also, ceramic supply stores
sometimes carry Bentonite, as it is a special clay used by potters.
During a vacation one year, I got my initial supply of Bentonite
directly from a refinery in Wyoming where they mine the stuff...
they gave me some bags of Bentonite free because the bags were slightly
ripped and they couldn't sell them.
To use the Bentonite, you dig a hole eight inches or more
in diameter, perhaps three feet deep (post-hole digger helps), and
suspend the ground rod in the middle. Put in a few inches of the
powdered or crushed Bentonite, water it thoroughly (it swells up
tremendously with water), and then add another layer. Water that
layer, and continue with water-soaked layers of Bentonite until
the hole is filled up.
The Bentonite absorbs the water, expands, and holds the ground rod
very tightly in the center. Because of the expansion and Bentonite's
conductive qualities, a lower resistance path to ground is achieved.
It's sort of like using an eight-inch diameter ground rod at your
site. The Bentonite never drys out, as it is "hydrophilic" and absorbs
moisture from the soil to remain hydrated.
If you do a web search on the term "bentonite" you'll come
up with a lot more information about this mineral. Besides improving
ground systems, it is used as a colloidal (suspension) product for
everything from vinyl plastics to chocolate(!) to cosmetics. Also,
Bentonite, in a highly refined form, is the key active ingredient
in disposable baby diapers (I'm not kidding!). I know this trivia
because Bentonite mining is one of the industries in the region
of Wyoming where my wife's family resides.
[It is also to be used as protective
shock absorber for nuclear waste, dumped deep inside Sweden's rocky
ground. -- hcdx editor]
Here in Bonney Lake, WA, our soil is very rocky, ancient
glacial debris from Mt. Rainier. Even though we live on a small
island and are surrounded by water, the soil is still very dry and
rocky. Bentonite surrounding my ground rods has improved the directionality
of my impedance-matched, terminated 175 ft. longwire. In my opinion
there was an improvement in directivity to Papua New Guinea and
Irian Jaya after improving the ground with Bentonite.
I also use the same ground for K9AY electronics (the head unit),
although I'm not positive this is really helping. It's worth a try,
though, especially for poor soil.
There was a IEEE paper written some years ago about Bentonite
grounds. The careful measurements and comparisons they did showed
clearly that resistance-to-ground was lowered when Bentonite was
used. This method is clearly preferred over adding various salts
to the soil... Bentonite won't corrode the ground rod nor harm the
soil or surrounding vegetation.