Hi, Folks.

Looking for some advice.

I want to create a grounded opening in the wall of my ham shack through
which I'll install each rf cable that enters the shack. I plan to bolt a
conductive plate to the wall ground that I'll fasten the ground side of each
coaxial cable to, then bolt a ground cable to each ground rod and the plate.

Is there a significant difference between using the galvanized steel ground
rods and copper to create an rf gound? The copper ones are more than double
the price - is it worth using them?

Thanks, Bob, VE7HS

On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote:

Is there a significant difference between using the galvanized steel ground
rods and copper to create an rf gound?

Hi Bob,

Two answers for that:
1. No difference whatever;
B. Neither make an RF ground.

Updates will follow this brief announcement.

73's
Richard Clark, KB7QHC

I used one 10 ft. copper clad steel ground rod and three 10 ft. copper
pipes. The pipes had 1/4 inch holes
drilled randomly throughout the bottom six feet and allowed me to annually
pour an epsom salt solution through them to enhance
ground conductivity. One copper pipe was set about 6 inches away from the
paired copper clad steel -- this
enabled the salt solution to salt the region of both. The two sets were
about ten feet apart and joined together
with heavy copper clad steel wire (Silver soldered). . To one set I attached
a number of random length radials running across the
yard (along two fence lines) and around the side of the house. They gave me
a real good ground as far as I
was concerned. Due to illness I recently sold the house, and extracted the
ground system. Surprisingly there was
little if any degredation of the metal elements -- that was after 27 years
in the ground! Both the copper clad steel
rod and the copper pipes were in good shape. Copper is expensive, but it
lasted a long time and took the
worry about whether I had a good ground away.

To install the copper pipes, I first drove in the copper clad steel rod,
then drew it out of the ground with
a car jack and inserted the copper pipes in the resultant holes.

To make the job easy, I had a young ham use a sledgehammer to drive the
copper clad steel pipe into
the ground and jack it back out -- three times! For the fourth hole I did
not have to extract the rod -- it
was left in place.

I'm no engineer, and never did any ground testing (whatever that involved),
but I was totally satisfied
with the system. Do it once right amd then don't worry about it!

Irv VE6BP





"Richard Clark" wrote in message
...
On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote:

Is there a significant difference between using the galvanized steel
ground
rods and copper to create an rf gound?

Hi Bob,

Two answers for that:
1. No difference whatever;
B. Neither make an RF ground.

Updates will follow this brief announcement.

73's
Richard Clark, KB7QHC

On Fri, 28 May 2010 11:17:28 -0600, "Irv Finkleman"
wrote:

I'm no engineer, and never did any ground testing (whatever that involved),

Hi Irv,

In fact you had the perfect opportunity to do simple but effective
test through a classic three electrode measurement.

You perform the test three times by rotation among the three
electrodes. You apply a HIGH voltage across the two most distant
electrodes, measure that current, and measure the potential difference
to the third, middle electrode. You must us a high voltage to
overcome local ground currents and any cathodic action. 50 or more
volts is enough.

73's
Richard Clark, KB7QHC

Richard Clark wrote:

On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote:

Is there a significant difference between using the galvanized steel
ground rods and copper to create an rf gound?

Hi Bob,

Two answers for that:
1. No difference whatever;
B. Neither make an RF ground.

Updates will follow this brief announcement.

73's
Richard Clark, KB7QHC

Looks like my follow up post didn't make it through.

Richard I intend these three ground rods to be the start of grounding my
station, not as a counterpoise for one of my antennas. These will be bonded
to my radios and the electrical service entrance ground.

Why do you say this does not make an RF ground?

Thanks, Bob

On Sat, 29 May 2010 17:04:16 -0700, Robert Smits
wrote:

Why do you say this does not make an RF ground?

Hi Bob,

If by "this" you mean the three rods, then they will NOT make an RF
ground.

Of necessity due to wavelength, your ground must be spread out (not
buried) to one quarter wavelength. For 160M, your radials (not ground
rods), should extend 40 meters from your radiator.

Classically, you would need 120 radials for an RF ground.

Classicism and practical reality diverge, so there are variations on
all of this EXCEPT ground rods do not make an RF ground.

73's
Richard Clark, KB7QHC

In article ,
Robert Smits wrote:

Richard Clark wrote:

On Thu, 27 May 2010 17:36:41 -0700, Bob Smits wrote:

Is there a significant difference between using the galvanized steel
ground rods and copper to create an rf gound?

Hi Bob,

Two answers for that:
1. No difference whatever;
B. Neither make an RF ground.

Updates will follow this brief announcement.

73's
Richard Clark, KB7QHC

Looks like my follow up post didn't make it through.

Richard I intend these three ground rods to be the start of grounding my
station, not as a counterpoise for one of my antennas. These will be bonded
to my radios and the electrical service entrance ground.

Why do you say this does not make an RF ground?

Thanks, Bob

A lot of folks, make the same mistake, in thinking that Electrical
Ground and RF Ground are the same thing. They, clearly, are NOT, the
same thing or even close to the same thing, unless you happen to be
living on a Salt Marsh. Ground Rods, of any kind, are only Electrical
Grounds. Rf Grounding is a Totally Different bag of cats. RF Grounds
need to be engineered, by someone who is familiar with Antenna Design
and Installation Procedures, for the particular Antenna and landscape,
where the antenna is to be installed.

In article ,
Richard Clark wrote:

Of necessity due to wavelength, your ground must be spread out (not
buried) to one quarter wavelength.

Richard-

I have a steel well pipe that is approximately a quarter wave on 40
Meters. Even though it is buried, why wouldn't this work as the bottom
half of a vertical dipole?

I tried it with a mobile whip as the vertical element. It worked better
than I expected, but not really well.

Fred
K4DII

On Mon, 31 May 2010 00:33:00 -0400, Fred McKenzie
wrote:

I have a steel well pipe that is approximately a quarter wave on 40
Meters. Even though it is buried, why wouldn't this work as the bottom
half of a vertical dipole?

Hi Fred,

One perspective of the radial field is that it shields the radiator
from the loss of ground. However, that simplification disguises the
fact that the radials radiate too - and unproductively. When every
radial's radiation is taken into consideration, opposite radials (each
one that is 180 degrees from the other) cancel.

That aside, their benefit is they conduct better than dirt. What this
means is more power goes into copper/steel instead.

Now, if we consider your well pipe, it goes deeper into that lossy
dirt and the deeper it goes, the more dirt the return signal (to the
other, the vertical radiator) has to go through. More loss than use.

OK, another reason. For as poor/well as dirt may conduct, it too has
skin effect. This means at some distance into the dirt, conductivity
plummets because of skin effect. Deeper yet, and the skin effect loss
increases at a quick clip.

As skin effect is frequency dependent, at really low frequencies, your
well pipe has some advantage. This frequency range is suitable for
working lightning whose top end is 1MHz. At 7 MHz, there's no point.

I tried it with a mobile whip as the vertical element. It worked better
than I expected, but not really well.

Which shows you how crummy the whip is because what well pipe there
was that was above ground was doing the job of the whip.

Step back and look at the big picture using your analogy of a vertical
dipole with half of it buried. Now, convert that buried half into
multistrand. Bend each strand 90 degrees so that each strand just
rides an inch or two above ground with all of the newly bent strands
in a flat circular spray around the upper half. Walla! as the French
say.

73's
Richard Clark, KB7QHC

It appears that you are a masochist [to yourself] or a sadist [to the kid you had use a sledgehammer !!! There is a much, much easier device, to place ground rods in place. It's called a 'Water Drill'. You use typically 3/4" galvanized steel pipe of the appropriate length {couple lengths together, as needed}, add a 1' 2' section at a right angle to the main vertical length, for rotational/insertion/extraction leverage. On the end of the short piece, add a female hose [with a water shut-off] to pipe adapter. On the vertical pipe, add a older style adjustable brass spray nozzle. You usually want a forceful stream. Simply place the nozzle end where you desire to begin a hole for the ground rod. Turn on the water (wear a raincoat/wetsuit, if you like), and apply slight downward pressure. You may need to alternately extract and reinsert, to allow dirt, from the hole being drilled, to escape.

This procedure, very possibly, may not work in VE6 land; in the wintertime. Where I live, I can drill a hole in usually less than 5 minutes, and drop in the ground rod shortly thereafter.