I'm confused about the requirements for a counterpoise for an end-fed wire antenna. I understand
that it's needed, but I don't understand what the requirements are.

Can a ground stake at the base of the feed point serve as a counterpoise, or does it need to be
another wire running under the ground below the antenna?

If a wire is required, how long does the counterpoise have to be?

Would it be better to use insulated or uninsulated wire for a buried counterpoise?

KJ4NTS wrote:
I'm confused about the requirements for a counterpoise for an end-fed wire antenna. I understand
that it's needed, but I don't understand what the requirements are.

If you get 100 replies, you'll probably get 110 different answers to that.


Can a ground stake at the base of the feed point serve as a counterpoise, or does it need to be
another wire running under the ground below the antenna?

No, it makes a good DC ground for lightening protection. A counterpoise can be
run almost anywhere, and the more the better.

If a wire is required, how long does the counterpoise have to be?

..28 wavelength is something I have read, while most people use 1/4 wavelength,
or an electrical equivalent (shorter due to velocity factor).

Would it be better to use insulated or uninsulated wire for a buried counterpoise?

Uninsulated.

Not that some antennas don't need a counterpoise, for example a 5/8th wave
antenna or an end fed zepp which uses no or a very short counterpoise.

A friend of mine has a commercial antenna, which consists of a matching
network, a trap and around 40 feet of wire. It covers 10,20 and 40 meters
with no counterpoise. The matching network can only handle 25 watts,

My speculation is that it's sort of a 5/8th wave type antenna with
loading coils to eletrically lengthen it.

It could also be a 50 ohm 25 watt resistor with a long tail on the "hot" end,
but I really doubt it.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

On Sun, 2 Aug 2009 17:30:31 GMT, "KJ4NTS" wrote:

I'm confused about the requirements for a counterpoise for an end-fed wire antenna. I understand
that it's needed, but I don't understand what the requirements are.

Hi OM,

What are YOUR requirements? (What bands, how long is it?)

Can a ground stake at the base of the feed point serve as a counterpoise, or does it need to be
another wire running under the ground below the antenna?

Both, and more wire(s).

If a wire is required, how long does the counterpoise have to be?

For single band operation? (You aren't very clear about this.) The
deeper into the ground (and deeper than 6 inches doesn't count for
much), the less resonant it will become. Make it as long as your wire
overhead - maybe less.

Would it be better to use insulated or uninsulated wire for a buried counterpoise?

Doesn't matter.

73's
Richard Clark, KB7QHC

I'm confused about the requirements for a counterpoise for an end-fed wire antenna.

What are YOUR requirements? (What bands, how long is it?)

Apparently this is not as important as you first imagined.

On Aug 2, 12:30*pm, "KJ4NTS" wrote:
I'm confused about the requirements for a counterpoise for an end-fed wire antenna. *I understand
that it's needed, but I don't understand what the requirements are.

Can a ground stake at the base of the feed point serve as a counterpoise, or does it need to be
another wire running under the ground below the antenna?

If a wire is required, how long does the counterpoise have to be?

Would it be better to use insulated or uninsulated wire for a buried counterpoise?

With regard to whether you need a counterpoise or not. If your
antenna has two wires at the open end (feed point) then they both must
be connected to the transmitter where there is also an additional
provision for a ground connection ( a must in all cases as the chassis
is floating).If the radiator has only one termination then only one
transmission wire can be connected to it leaving the other wire to be
connected to a ground system which in effect balances your radiator
with a load that does not radiate unless it is the form of a
counterpoise. The effectiveness of your ground system can be measured
by its effectiveness in supplying a resistive feed impedance somewhat
near 30 ohms (above 20 ohms) or so where your transmitter does not
encounter any problems, a counterpoise will present a higher
impedance. An end fed antenna cannot be of a fractional wavelength and
thus the ground field or counterpoise is required to be added to
provide an impedance that can be fed by the transmitter without a
problem so you can enjoy useage of your antenna

"Art Unwin" wrote in message
...
On Aug 2, 12:30 pm, "KJ4NTS" wrote:

ART IS BACK!

don't believe a thing he says, even if you think it kind of makes sense,
which it doesn't.

On Aug 2, 3:01*pm, Art Unwin wrote:

An end fed antenna cannot be of a fractional wavelength...
_________________

? ?

Art, note that the vertical monopoles used by MW broadcast stations
are ALL fractional-wavelength radiators, and probably 99% of them are
end fed.

On Aug 3, 5:24*am, Richard Fry wrote:
On Aug 2, 3:01*pm, Art Unwin wrote:

An end fed antenna cannot be of a fractional wavelength...

_________________

? ?

Art, note that the vertical monopoles used by MW broadcast stations
are ALL fractional-wavelength radiators, and probably 99% of them are
end fed.

I regard a radiator with a counterpoise as being center fed of a
given impedance to connect to regardles whether the counterpoise is
above ground or not. If a radiator is of a closed cuircuit form it may
be fed at any point in physical terms. Other peoples definitions may
vary. The poster I understood to be at the position of the end of a
transmission line with two wires in hand and wanted advice from that
point to procede. If his advisers are going to quibble then he needs
to go elsewhere for advise or settle for a poll.

"Art Unwin" wrote in message
...
On Aug 3, 5:24 am, Richard Fry wrote:
On Aug 2, 3:01 pm, Art Unwin wrote:

An end fed antenna cannot be of a fractional wavelength...

_________________

? ?

Art, note that the vertical monopoles used by MW broadcast stations
are ALL fractional-wavelength radiators, and probably 99% of them are
end fed.

I regard a radiator with a counterpoise as being center fed of a
given impedance to connect to regardles whether the counterpoise is
above ground or not. If a radiator is of a closed cuircuit form it may
be fed at any point in physical terms. Other peoples definitions may
vary.

This is a simplified way of looking at things. It only works if he is to
use a horizontal loop, but doesn't address matching the antenna to the line
and in the case of "two pieces of wire", you won't have a clue where the
electrical "center" is. One of the original posts was about a dipole where
the coax would have to follow one of the legs because it would hang down
where it shouldn't be. That makes the feed point NOT in the center and
prone to common mode currents on the line.

It took me a couple of posts to realize the Poster has made multiple posts
questioning different aspects of his problem and we get the whole scenario
from chasing down all his threads.

It looks to me that his real estate won't allow a balanced antenna anyway,
so he will have to deal with the issues of an unbalanced radiator anyway. I
first thought of an Inverted L as an optimal antenna for his situation, with
remote matching for multi-band operation to keep RF out of the shack. An
elevated horizontal loop or off center fed dipole with ladder line to a
tuner at the entrance of the shack would also be an answer to the problem.
A multi-band vertical would be a good choice for 30-10 meters. Although
they work for 40 and 80, the pattern is not as good as a horizontal antenna
for exploiting the shorter skip.

On Aug 3, 11:17*am, "JB" wrote:
"Art Unwin" wrote in message

...
On Aug 3, 5:24 am, Richard Fry wrote:

On Aug 2, 3:01 pm, Art Unwin wrote:

An end fed antenna cannot be of a fractional wavelength...

_________________

? ?

Art, note that the vertical monopoles used by MW broadcast stations
are ALL fractional-wavelength radiators, and probably 99% of them are
end fed.
I regard a radiator with a counterpoise *as being center fed of a

given impedance to connect to regardles whether the counterpoise is
above ground or not. If a radiator is of a closed cuircuit form it may
be fed at any point in physical terms. Other peoples definitions may
vary.

This is a simplified way of looking at things. *It only works if he is to
use a horizontal loop, but doesn't address matching the antenna to the line
and in the case of "two pieces of wire", you won't have a clue where the
electrical "center" is. *One of the original posts was about a dipole where
the coax would have to follow one of the legs because it would hang down
where it shouldn't be. *That makes the feed point NOT in the center and
prone to common mode currents on the line.

It took me a *couple of posts to realize the Poster has made multiple posts
questioning different aspects of his problem and we get the whole scenario
from chasing down all his threads.

It looks to me that his real estate won't allow a balanced antenna anyway,
so he will have to deal with the issues of an unbalanced radiator anyway. *I
first thought of an Inverted L as an optimal antenna for his situation, with
remote matching for multi-band operation to keep RF out of the shack. *An
elevated horizontal loop or off center fed dipole with ladder line to a
tuner at the entrance of the shack would also be an answer to the problem..
A multi-band vertical would be a good choice for 30-10 meters. *Although
they work for 40 and 80, the pattern is not as good as a horizontal antenna
for exploiting the shorter skip.

You are correct. I should NOT have given a simplified response to a
simple question.
Your technical answer is a much better response tho I suppose I could
have made mine as technical so that he would not ask questions any
more! Good point about common mode. That should screw him up as well
as other things that you inserted with respect to how does one connect
to an antenna. We could ask him I suppose how many wires he intends to
connect to his intended antenna feed point, and if it is not two then
question how he intends to measure the impedance for matching
purposes. Yup, I could have done a better job.