Ground rods in rocky soil
 

I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil? The
topsoil on my property tends to be very shallow, at times only 12 in. deep.
I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

Phil, K4NE

Hi Phil:

Two thoughts on your question. First it sound like your putting in the
ground rod for RF grounding reasons. Ground rods are very poor RF grounds.
Grounds rods are for lighting and electrical safety not RF. If you want a
good RF ground plus electrical protection ground putting in a ground rod
plus as many buried radials of what ever length you can manage will do the
job much better.
Second, I have 6 ground rods in my tower installation. The ground here is
rocky also, which made putting them in not something I looked forward to. In
the end I used an electric jack hammer to put them in. It had a cup adapter
in place of the normal bit. I started the rod by hand with a big hammer and
then muscled the electric jack hammer up and finished the job. The hardest
part was lifting the jack hammer up to reach the top of the ground rod. This
is a lot easier if you have some help. The jack hammer belonged to a friend
but I'm sure that a large rental store should have them.


--
John Passaneau, W3JXP
Penn State University


"Northern Lights" wrote in message
news:1069183285.115652@rh9cache2...
I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil?
The
topsoil on my property tends to be very shallow, at times only 12 in.
deep.
I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

Phil, K4NE

Phil,
In line with the previous suggestion, if you can't
go 'down', go side ways. 'Depth' isn't what does the
job.
'Doc

Howdy,

I never buy so-called "ground rods". Instead I use 3/4-inch Cu tubing and
connect it to the end of my garden hose.

I turn on the water and push the end of the tubing into the ground. The water
pressure makes it easy to push the rod into the ground.

HOWEVER: Depending on how "rocky" the soil is, it may be a little harder than
if the soil is un-rocky. (It's a much better hint for softer soil.)

BTW Cu tubing is much cheaper than a ground rod.

73 de Jack, K9CUN

BTW Cu tubing is much cheaper than a ground rod.

.................................................. ......

But it is still a waste of effort and money for a ground connection
resistance of 50, 100, 200 ohms or more.

Go horizontal with radial wires. Shallow-buried. Or lay on the surface if
that's all you can manage.

Phil:

Have any building projects coming up???

When I built my workshop, I tied the rebar perimeter together and ran a #6
copper wire in the trench. Also put a number of #12 wires under the vapor
barrier (on top of the compacted fill, and below the plastic vapor barrier.
Brought each wire down to a common point at the corner of the room that is now
my Ham Shack. I'd guess there's somewhere over 700 feet of bare copper wire
laying under there... The slab is 32 x 52 feet, and the individual copper wires
range from 50 to 66 feet long, and they are cross connected at a couple of
random places across the narrow dimension of the slab. It's clearly the best
"ground" I've ever had.

There wasn't a ghost of a chance of driving conventional ground rods, as I live
on solid Lava, which has what the locals call "Blue Rock" underlying (which is
just more lava, but with higher density). The rock is so hard, it will stop a
D-9 Caterpillar using a single claw ripper in it's tracks, even if they are
only ripping less than a foot deep. Ripping and leveling a lot here takes more
than a bit of time, particularly compared to dirt or mixed dirt and rock!

Even if I wasn't putting up a building, I'd be thinking about how I could get a
decent grid of copper out there, even if I had to lay it out on the ground and
put an inch of dirt on top and grow new grass.... If I ever move, I know I'll
be doing something similar.

-_Rick AH7H



Northern Lights wrote:

I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil? The
topsoil on my property tends to be very shallow, at times only 12 in. deep.
I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

Phil, K4NE

Phil, get a piece of PVC or ABS pipe, large enough to slide the ground rod
into. Glue an adapter to the pipe that will allow you to connect it to a
garden hose. With the ground rod inside the pipe, turn the water on, and
let it drill the ground rod in for you. Unless we're talking solid rock,
this works pretty well even with hardpan.

Uh, BTW, what are you grounding?

73,
Mike KI6PR
El Rancho R.F., CA

"Northern Lights" wrote
I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil?
The
topsoil on my property tends to be very shallow, at times only 12 in.
deep.
I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

Phil, K4NE

Mikey wrote:

Phil, get a piece of PVC or ABS pipe, large enough to slide the ground rod
into. Glue an adapter to the pipe that will allow you to connect it to a
garden hose. With the ground rod inside the pipe, turn the water on, and
let it drill the ground rod in for you. Unless we're talking solid rock,
this works pretty well even with hardpan.

Uh, BTW, what are you grounding?

73,
Mike KI6PR
El Rancho R.F., CA

"Northern Lights" wrote

I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil?

The

topsoil on my property tends to be very shallow, at times only 12 in.

deep.

I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

I hear people speaking of simply laying wire on the ground being better
than a rod type ground.

Is this serious? I'm trying to envision this, and even if it works
electrically, it seems like rather dangerous advice in many ways.

- Mike KB3EIA -

Mike,
Yes, it's serious, many times a ground radial system
will be 'better' than a ground rod(s). Given the rocky
ground as in the original post, a radial system would be
much preferable to ground rods.
Given that you get the wires deep enough to be missed
by the lawn mower, what's so dangerous about it?
'Doc

Two possibilities:

1. Try a ground plate. They have the same surface area as the rod, but you
still have to bury it. However, you will still have to find an area you can
dig a hole 1' x 1.5' x (as deep as you can get it, but deeper than 3' should
not be necessary.) How is the moisture in the earth? If it's dry, you have
yet another problem.

2. Buy a 1/2" x 10' copper pipe, thick wall. Solder on a tee (sideways) and
cap the top side, and mount a hose fitting on the perpendicular opening and
attach your garden hose. Cut the 'drilling' end of the pipe off on a slight
angle. (30 degrees?) Now, use a rubber mallet and some finesse, turn on the
water and see if you can coax it down as far as possible. If you hit a big
flat rock surface, you're buggered, but if with a little luck you might get
at least 8+ feet of it into the earth.

Good luck!

Pat

On Tue, 18 Nov 2003 14:21:40 -0500, Northern Lights wrote:

I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil? The
topsoil on my property tends to be very shallow, at times only 12 in. deep.
I would rather use earth ground and not go the route of an artificial
ground.

I used a rotary impact drill in my rocky soil. I had to grind a littl off
of the rod to get it to fit but worked fine.

BTW, don;t use the RS ground rod. Very thin plating

'Doc wrote:


Mike,
Yes, it's serious, many times a ground radial system
will be 'better' than a ground rod(s). Given the rocky
ground as in the original post, a radial system would be
much preferable to ground rods.
Given that you get the wires deep enough to be missed
by the lawn mower, what's so dangerous about it?
'Doc

If it is under the surface, then no problem. But I'm referring to the
laying the wires on the ground comment I've heard of a few times here.
And that would be dangerous for people crossing the lawn, and myself,
after the XYL is done with me! 8^)

- Mike KB3EIA -

Simply lay the wires on the ground. Take old coat hangers and cut 6" pieces
from them. Fold in half and place over the radial wire stapling it to the
ground. By next spring you will not be able to find a wire let alone trip
over it.


"Mike Coslo" wrote in message
t...
'Doc wrote:


Mike,
Yes, it's serious, many times a ground radial system
will be 'better' than a ground rod(s). Given the rocky
ground as in the original post, a radial system would be
much preferable to ground rods.
Given that you get the wires deep enough to be missed
by the lawn mower, what's so dangerous about it?
'Doc

If it is under the surface, then no problem. But I'm referring to the
laying the wires on the ground comment I've heard of a few times here.
And that would be dangerous for people crossing the lawn, and myself,
after the XYL is done with me! 8^)

- Mike KB3EIA -

One h_ll of a problem.

First: What do You need the ground rods for?
Is it RF earth or lightening protection.

For Lightening protection, almost anything will do. Remember, You only will
have
to make it EASIER for the lightning to take a predictable way, than taking a
un-predictable one. Just drill a hole, put in the rod, put some soil in the
hole and
enjoy.

For RF ground, things go from acceptable to nightmare(-ish). First of all, You
will
need at least three rods. Then, You HAVE soil on Your property. 1 foot of it
(30 cm). What you do now, is to take out the showel, and start digging. Three
holes, in a triangle some 10 feet apart. The diameter of the holes, say 2 feet.

Dig until You hit the rocks. Then, find an electric or pneumatic drilling
machine.
There are excellent machines that makes holes in rock as it was butter. Then,
You
put in 3 rods, length about 4 feet in the holes. The small hole in the rock is
filled
with salt (NaOH). The digged part of the holes are filled up to 3/4 (You need
a small part below ground level for "refilling") with a mixture 50% soil, 50%
salt.
Then You dig a ring around EACH hole. This ring is 4'' deep, 4" wide.
Connect Your rods to Your RF earth system. Before You plan to go QRV, take
a watering can, and fill the rings with water 1 hour in advance (dry season
only). Two times a year, You fill the holes with extra salt, until it reaches
ground
level (the "refilling" described above).

Remember, that Your plants will die, and perhaps, thus Your marriage. Your
Neighbors
will turn their dislike of radio amateurs into pure hate. A small price for a
decent RF
ground in rocky environment! You COULD of course use wires instead. But that's
cheating!


Northern Lights wrote:

I have a mundane question.

Does anyone have suggestions for installing ground rods in rocky soil? The
topsoil on my property tends to be very shallow, at times only 12 in. deep.
I would rather use earth ground and not go the route of an artificial
ground.

I think I know the answer to my question but wanted to see if anyone out
there had a silver bullet solution.

Phil, K4NE

Nisse wrote:

For Lightening protection, almost anything will do. Remember, You only will
have
to make it EASIER for the lightning to take a predictable way, than taking a
un-predictable one. Just drill a hole, put in the rod, put some soil in the
hole and enjoy.

If you honestly think this is Lightening (sic) protection, I wouldn't
put any antennas higher than three feet if I were you.


73 ... WA7AA


--

Anti-spam measu look me up on qrz.com if you need to reply directly

Just drill a hole, put in the rod, put some soil in the
hole and enjoy.
If you honestly think this is Lightening (sic) protection, I wouldn't
put any antennas higher than three feet if I were you.
Reminds me of the joke of astronauts taking a barrel of dirt with them
into outer space so they could be buried if they died out there.