Everybody acknowledges that a good ground is required for any amateur
work, especially for a vertical. When I'm putting in an RF ground for
either my station or for an antenna system, how do I know when I've
achieved "good enough"? What works?

===================================

Anything will work!

To summarise, begining with 1 radial, all you can do is keep laying more
radials until performance ceases to improve. Then that's the best which can
be done at your QTH. Performance can be judged by measuring the strength of
fixed, stable, not too distant, MF and lower frequency HF radio stations in
daylight. There's an effect known as "Reciprocity" which means that an
antenna with its ground system is just as good or bad on transmit as it is
on receive.

If you increase the number of shallow-buried radials by 50 percent and
there's no noticeable improvement then stop laying. Depending on the type of
soil you will end up with a number which, in general, will be fewer than
what you thought of before you started.

With a vertical, much depends on the lowest frequency of interest. Opinions
differ but in my opinion, in average garden soil, there's not much point in
laying shallow buried radials longer than 1/10th of a wavelength. They can
be shorter in very fertile, fine, damp soil and longer in dry sandy or rocky
soil. Fertility is the key. Increase their number according to the above 50
percent guidline.

Layout and bends in the wires are unimportant as are varying lengths. Just
spread them out fairly uniformly over the area available. A 180-degree
missing sector because the house gets in the way is not of great
consequence.

Wire diameter has little electrical effect. Choose wire diameter according
to type of soil and wire durability.

Forget about ground rods. A ground rod is little better electrically than a
horizontal radial of about the same length. A short ground rod can be used
as a common connecting point.

If you like amusing yourself with numbers, and for crude predictions of what
to expect, download programs EARTHRES and RADIALS2 from website below. A
little knowledge of your local soil resistivity can add much to the interest
and help you to forget the lumbago.
---
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

I should have mentioned. When measuring signal strengths as a measure of
performance there's safety in numbers. Take the average of a fair number of
transmissions, all well above the noise level, at about the same time each
day, using your most stable S-meter with the receiver gain turned down such
that the meter deflection is on the most sensitive sector of its scale.
Allow the receiver to warm up for the same length of time on each occasion
it is used.

S-meter calibration doesn't matter two hoots.

And once set, don't ever touch the receiver gain control.

You should take all these precautions from the time when you have laid only
one radial. You will not wish to dig up already laid radials in order to
re-measure the earlier ones you forgot to treat in the standard manner.

It will be appreciated, to make tests during radial-laying operations by
asking for signal strength reports from your many friends, using THEIR
S-meters, will result in you losing them.

Incidentally, when "I" used this method of testing antenna efficiency I
stopped at 8, 10 feet, radials with a 3 feet rod at the end of each. This
included the domestic incoming main water pipe which made no difference when
THAT was connected. So I stopped.

But my soil resistivity is only about 70 ohm-metres. I can grow anything in
my garden. At present it is covered with a dense growth of 3 feet high
weeds except for a small patch which I use to feed the birds. As if they
didn't get enough to eat anyhow. With the trees and overgrown bushes it is
a wild-life sanctuary for frogs, rats, squirrels and hedgehogs. The only
complaints I get are from the neighbours. But its stopped them complaining
about TVI.
---
Reg, G4FGQ

"Reg Edwards" wrote in message
...
I should have mentioned. When measuring signal strengths as a measure of
performance there's safety in numbers. Take the average of a fair number
of
transmissions, all well above the noise level, at about the same time each
day, using your most stable S-meter with the receiver gain turned down
such
that the meter deflection is on the most sensitive sector of its scale.
Allow the receiver to warm up for the same length of time on each occasion
it is used.

S-meter calibration doesn't matter two hoots.

And once set, don't ever touch the receiver gain control.

You should take all these precautions from the time when you have laid
only
one radial. You will not wish to dig up already laid radials in order to
re-measure the earlier ones you forgot to treat in the standard manner.

It will be appreciated, to make tests during radial-laying operations by
asking for signal strength reports from your many friends, using THEIR
S-meters, will result in you losing them.

Incidentally, when "I" used this method of testing antenna efficiency I
stopped at 8, 10 feet, radials with a 3 feet rod at the end of each. This
included the domestic incoming main water pipe which made no difference
when
THAT was connected. So I stopped.

But my soil resistivity is only about 70 ohm-metres. I can grow anything
in
my garden. At present it is covered with a dense growth of 3 feet high
weeds except for a small patch which I use to feed the birds. As if they
didn't get enough to eat anyhow. With the trees and overgrown bushes it
is
a wild-life sanctuary for frogs, rats, squirrels and hedgehogs. The only
complaints I get are from the neighbours. But its stopped them
complaining
about TVI.
---
Reg, G4FGQ


Sounds a little like my counterpoise. 12 wires 12ft long, Short ground rod
at far end of each wire just to pin it down. 10ft 2inch pipe in the middle
for ground/ mount. You can get an idea of resistance to ground by
connecting 120 VAC to the ground system through a fuse and see how big of a
fuse you can blow. I rigged a fuse holder with a neon blown fuse indicator
to a piece of PVC pipe. last time I checked mine it would pop a 10amp fuse.

Nice Site,

John-WA4JM

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