water well ground system
 

I have access to a 65' water well that I could install a radial in. This
is sulfur water and the conductivity is quiet high (per the lab
analysis). I was wondering if this would make a good ground system for a
vertical on 160/75/40. I am sitting on 6' of sandy loam which is sitting
on solid limestone bedrock. I've heard of people wanting to use the well
casing or tubing, but I would like to install a copper wire. Any
comments, suggestions or debate welcome

73's

Richard

Richard wrote in message link.net...
I have access to a 65' water well that I could install a radial in. This
is sulfur water and the conductivity is quiet high (per the lab
analysis). I was wondering if this would make a good ground system for a
vertical on 160/75/40. I am sitting on 6' of sandy loam which is sitting
on solid limestone bedrock. I've heard of people wanting to use the well
casing or tubing, but I would like to install a copper wire. Any
comments, suggestions or debate welcome

73's

Richard

I don't think it would work all that well. But I've never tried it.
Would be about the same as running a ground wire straight down into
the ground. Which is not very good. You still would have no radials on
the surface of that lossy ground. And thats where the radials really
count. A radial going straight down into the ground will be fairly
useless for rf purposes to my way of thinking. But maybe others will
throw in their opinions...You could use it as a center grounding
point, but I would still lay out radials on the surface of the ground.
It sounds like you are on fairly lossy earth. MK

W7TI wrote:

On Sun, 26 Oct 2003 22:07:50 GMT, Richard wrote:

I have access to a 65' water well that I could install a radial in. This
is sulfur water and the conductivity is quiet high (per the lab
analysis). I was wondering if this would make a good ground system for a
vertical on 160/75/40. I am sitting on 6' of sandy loam which is sitting
on solid limestone bedrock. I've heard of people wanting to use the well
casing or tubing, but I would like to install a copper wire. Any
comments, suggestions or debate welcome

__________________________________________________ _______

This reminds me of the April article in QST years ago about digging a
trench, filling it with water and using it as a yagi reflector.

The spirit lives on!

--
Bill, W7TI

Yep. It worked really great, but it was an unholy bitch
getting that trench up 30' to the back of the boom.

On Sun, 26 Oct 2003 22:07:50 GMT, Richard
wrote:

I have access to a 65' water well that I could install a radial in. This
is sulfur water and the conductivity is quiet high (per the lab
analysis). I was wondering if this would make a good ground system for a
vertical on 160/75/40. I am sitting on 6' of sandy loam which is sitting
on solid limestone bedrock. I've heard of people wanting to use the well
casing or tubing, but I would like to install a copper wire. Any
comments, suggestions or debate welcome

It makes an excellent *safety* ground. Not much in the way of a
radial though.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

73's

Richard

Richard,
Don't bother, wouldn't be worth the trouble. Use
the wire as radial instead.
'Doc

"W7TI" wrote in message
...
On Sun, 26 Oct 2003 22:07:50 GMT, Richard wrote:

This reminds me of the April article in QST years ago about digging a
trench, filling it with water and using it as a yagi reflector.

The spirit lives on!

--
Bill, W7TI

I forgot about that April Fool's issue article ... great memory !

GB

Richard wrote:
"I have access to a 65 ft. water well that I could install a radial in."

A radio wave traveling along the surface of the earth has its electric
lines of force tilted slightly forward so that the direction of
propagation is tilted slightly downward. The earth is a poor conductor
as compared with copper. The earth absorbs and dissipates some of the
wave`s energy.

Skin effect is the phenomenon of high-frequency current concentration on
a conductor`s surface. Skin effect applies to earth as it applies to
copper, butthe

Richard wrote:
"I have access to a 65 ft. water well that I could install a radial in."

A radio wave traveling along the surface of the earth has its electric
lines of force tilted slightly forward so that the direction of
propagation is slightly tilted downward. The earth is a poor conductor
as compared with copper. The earth absorbs and dissipates some of the
wave`s energy.

Skin effect is the phenomenon of high-frequency current concentration on
a conductor`s surface. Skin effect applies to earth as it applies to
copper, but the penetration depth depends on wavelength and resistivity
of the conductor. At 1 MHz, r-f penetrates copper to an effective depth
of only 0.0026 in.. The effective skin thiclkness (penetration depth) in
the earth depends on its dielectric constant. In ordinary soil the
dielectric constant may be 15 and may vary with moisture in the soil.
Water has a dielectric constant of about 80. Very dry soil may have a
dielectric constant of only 2 to 5. Soil conductivity varies from 1 mmho
to 40 mmhos.

At I MHz, the effective skin thickness of the earth, with good soil
conductivity of 36 mmhos per meter, is about 8.5 feet. At a soil
conductivity of 6 mmhos per meter it is 20 feet. For a poor conductivity
of 1 mmho per meter the skin thickness of the earth is about 50 feet at
1 MHz.

Sea water has a dielectric constant of 80, and has an effective skin
thickness at 1 MHz of 0.738 feet.

Skin effect thickness varies inversely with the square root of
frequency.

Point is that contact with the soil at a 65-foot well depth is not
important at h-f, as r-f current flow at h-f is mostly confined to the
surface of the earth. Skin effect will confine the r-f path from the
water surface at the bottom of the well to the surface of the well bore
back out of the well to the surface of the earth around the well, if the
r-f can be caused to go down the well at all. Highly conductive radials
at the surface are the key to an effective ground for h-f unless you are
lucky enough to be in close contact with water in the sea..

Best regards, Richard Harrison, KB5WZI

Sorry I fat fingered the wrong button sending off an incomplete post.

I read the "Organic Reflective Elements for the Simple Dipole" in April
1973 "OST" It`s the issue with M. Walter Maxwell`s picture on page 35.
There is no connection between these stories in "QST".

The place for a story such as the reflecting water-filled trenchs would
have been in "Radio-Craft".

Best regards, Richard Harrison, KB5WZI

The assumption that the skin depth varies inversely as the square root
of frequency is valid only for good conductors. Most types of soil fit
this category only at low frequencies, with the transition falling on or
near the HF range. For example, average soil (conductivity of 5 mS/m,
dielectric constant of 13) behaves like a conductor only below about 7
MHz. Above that, it's more like an insulator, where the skin depth stays
constant with frequency. Here are the skin depths in feet for average
soil at various frequencies:

0.25 MHz 47.6
0.5 MHz 34.2
1 MHz 25.0
2 MHz 19.0
4 MHz 15.4
7 MHz 13.8
10 MHz 13.2
100 MHz 12.6
1 GHz 12.6

There's a very good discussion of this in Kraus' _Electromagnetics_.

This doesn't alter Richard's conclusion that radials near the surface
make a much better ground than a single vertical conductor or
"connection" to ground.

Roy Lewallen, W7EL

Richard Harrison wrote:
Richard wrote:
"I have access to a 65 ft. water well that I could install a radial in."

A radio wave traveling along the surface of the earth has its electric
lines of force tilted slightly forward so that the direction of
propagation is slightly tilted downward. The earth is a poor conductor
as compared with copper. The earth absorbs and dissipates some of the
wave`s energy.

Skin effect is the phenomenon of high-frequency current concentration on
a conductor`s surface. Skin effect applies to earth as it applies to
copper, but the penetration depth depends on wavelength and resistivity
of the conductor. At 1 MHz, r-f penetrates copper to an effective depth
of only 0.0026 in.. The effective skin thiclkness (penetration depth) in
the earth depends on its dielectric constant. In ordinary soil the
dielectric constant may be 15 and may vary with moisture in the soil.
Water has a dielectric constant of about 80. Very dry soil may have a
dielectric constant of only 2 to 5. Soil conductivity varies from 1 mmho
to 40 mmhos.

At I MHz, the effective skin thickness of the earth, with good soil
conductivity of 36 mmhos per meter, is about 8.5 feet. At a soil
conductivity of 6 mmhos per meter it is 20 feet. For a poor conductivity
of 1 mmho per meter the skin thickness of the earth is about 50 feet at
1 MHz.

Sea water has a dielectric constant of 80, and has an effective skin
thickness at 1 MHz of 0.738 feet.

Skin effect thickness varies inversely with the square root of
frequency.

Point is that contact with the soil at a 65-foot well depth is not
important at h-f, as r-f current flow at h-f is mostly confined to the
surface of the earth. Skin effect will confine the r-f path from the
water surface at the bottom of the well to the surface of the well bore
back out of the well to the surface of the earth around the well, if the
r-f can be caused to go down the well at all. Highly conductive radials
at the surface are the key to an effective ground for h-f unless you are
lucky enough to be in close contact with water in the sea..

Best regards, Richard Harrison, KB5WZI