Probably the best DX site in the world
 DX news
Great 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 to earth.
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.
Front page
DX News
Andes DX
DX Lab
In Print
Web Stories

Web Archive
Mail Archive

Search all HCDX
mail since 1995

 About us
About us
Write to us

HCDX mail list

antennX  Cebik  FM antennas  Werner's links  Antenna Elmer  Coax basics