I am installing a short tower. The soil is very dry, mostly volcanic ash
and low conductivity. I had the backhoe operator dirll several holes 4
feet deep for grounding. It is impossible to drive a ground rod deeper
than 4 feet due to bedrock. What should I use to fill the holes after
the ground rods are installed?

You are lucky to have 4 feet. I have 8 inches or less around my house.
Zero behind the garage.

Is this going to be an antenna or just a tower for an antenna? Is the
area irrigated/watered for grass? If an antenna, you will need to
install a bunch of radials on or just under the ground surface. If you
are trying to ground the tower for lightening protection, I guess I
would mix a bunch of granular commercial fertilizer in with the soil as
I packed it around the ground rods. Then lots of water on the area.

Did you also have holes placed for guy wire anchors?

Paul, KD7HB

wrote in message
oups.com...
You are lucky to have 4 feet. I have 8 inches or less around my house.
Zero behind the garage.

Is this going to be an antenna or just a tower for an antenna? Is the
area irrigated/watered for grass? If an antenna, you will need to
install a bunch of radials on or just under the ground surface. If you
are trying to ground the tower for lightening protection, I guess I
would mix a bunch of granular commercial fertilizer in with the soil as
I packed it around the ground rods. Then lots of water on the area.

Did you also have holes placed for guy wire anchors?

Paul, KD7HB

I believe the aim is to get more conductivity from the soil. That being the
case, I would pour rock salt in the holes.

west

I saw a group of reps from MITRE solve a radar grounding issue by tying
the ground line to a 4'X8' copper plate and burying the plate in a 6'
deep pit filled with copper sulfate crystals. Threw in water, waited
and, viola, decent ground in granite rock mountain top.

-Bob

I am installing a short tower. The soil is very dry, mostly volcanic ash
and low conductivity. I had the backhoe operator drill several holes 4
feet deep for grounding. It is impossible to drive a ground rod deeper
than 4 feet due to bedrock. What should I use to fill the holes after
the ground rods are installed?

Do a web-search for "bentonite" and "ground", and you'll learn lots!

Although I've never used it (but I'm going to start!), "bentonite" is
the appropriate stuff to use. When wet, it expands inward to squeeze
the ground rod and outward to press firmly against the soil, thereby
resulting in (effectively) a very large-diameter ground well-connected
to the soil.

Clumping-type kitty-litter is supposedly bentonite (a clay material),
so it should be relatively cheap.
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

On 22 Dec 2005 13:53:30 -0600, wrote:

I am installing a short tower. The soil is very dry, mostly volcanic ash
and low conductivity. I had the backhoe operator drill several holes 4
feet deep for grounding. It is impossible to drive a ground rod deeper
than 4 feet due to bedrock. What should I use to fill the holes after
the ground rods are installed?

Do a web-search for "bentonite" and "ground", and you'll learn lots!

Although I've never used it (but I'm going to start!), "bentonite" is
the appropriate stuff to use. When wet, it expands inward to squeeze
the ground rod and outward to press firmly against the soil, thereby
resulting in (effectively) a very large-diameter ground well-connected
to the soil.

Clumping-type kitty-litter is supposedly bentonite (a clay material),
so it should be relatively cheap.

Hi Myron, how are you these days? If I recall, bentonite is used in
the oil patch as a slurry to seal the drill hole. It is called
drilling mud in that context. It should be pretty cheap!

Russ

On Fri, 23 Dec 2005 03:24:56 GMT, Russ wrote:

Hi Myron, how are you these days? If I recall, bentonite is used in
the oil patch as a slurry to seal the drill hole. It is called
drilling mud in that context. It should be pretty cheap!

It is also used in sand foundries in their molding sand.

Danny, K6MHE




email: k6mheatarrldotnet
http://www.k6mhe.com/