Elecraft

Counterpoises and Grounding

Classic

List

Threaded

10 messages Options

Stan GW3SRM

Counterpoises and Grounding

I note that the subject of counterpoises has been debated many times in this
forum but I have not seen the subject of tuneable artificial grounds
discussed. As no doubt many are aware, operating from a location remote from
the ground has its problems in ensuring effective grounding, especially with
end fed wire antennas. I have this problem as I operate from an upstairs
shack. I have overcome the difficulty by using a tuneable counterpoise
arrangement in conjunction with my end fed wire antenna. The EFW antenna is
approximately 66ft (20m) long and the counterpoise wire 16ft (5m).

Using my homebrew AGT and my KX3 is a simple process to tune for resonance.
a) Tune to the desired frequency using the internal KX3 auto tuner. b) Tune
for maximum current using the AGT meter (low power recommended for tuning).
Repeat the process as necessary to obtain best match. Usually 1:0 or 1:1
(KX3 reading). I only operate with 5 or 10 Watts. Apart from overcoming
grounding problems you get a resonate grounding system not an approximately
resonate one as used in most circumstances. This in my view, is a suitable
compromise in overcoming difficult grounding conditions, although I do not
advocate it in preference to an extensive grounding system where conditions
permit. One point to note is that if an external power supply is used the
output must be isolated from ground and suitable precautions taken against
lighting strikes. Many designs for simple homebrew AFT projects are
available on the web and MFJ also do one commercially. Obviously different
or different multiple lengths of counterpoise wires can be used to get the
best setup with your antenna.

73 Stan GW3SRM

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Jim Brown-10

Re: Counterpoises and Grounding

On Sat,6/10/2017 11:40 AM, Stan GW3SRM wrote:
> I note that the subject of counterpoises has been debated many times in this
> forum but I have not seen the subject of tuneable artificial grounds
> discussed.

Fundamental concepts like this are very well addressed in the classic
references on antennas. Your use of the word "counterpoise" is precisely
correct. Your use of the word "ground" is absolutely and totally WRONG.

A connection to Mother Earth does NOT make a transmitting antenna work
better. The earth is a big resistor. Shoving TX RF into it wastes TX
power by warming worms.

What IS needed, no matter where you operate, is a return for antenna
current -- SOMETHING to act as the other half of the antenna. Antennas
like a dipole inherently provide that; with an end fed antenna, we must
supply that "other half," and the correct name for it is "counterpoise."

Transmitters are designed to work into some defined load Z, usually 50
ohms, but with some tolerance. That tolerance is often defined by the
apparent SWR as measured at the transmitter. The function of an antenna
tuner is to transform the Z at the transmitter end of the feedline to
the Z that the transmitter want to see -- that is, the Z into which it
will provide the most power, and do so without stressing the output
transistors or tubes. The so-called "artificial grounds" provide the
same function, but in a different way -- they vary the electrical length
of the counterpoise so that the combination of the "intentional antenna"
(the end fed wire) and the counterpoise make the Z at the transmitter as
close as possible to 50 ohms. This allows the TX to put power into the
antenna. That counterpoise, whatever it is, is PART OF THE ANTENNA. And
that's true whether we CALL it "ground" or counterpoise.

Another point. ALL end-fed antennas must put their return current
SOMEWHERE. If we don't provide a "good" path (like a good
counterpoise), mother nature will take over and put the current where
SHE wants it to go, like anything attached to the chassis of the
transmitter. This can be a coax shield, the power system protective
earth (green wire), a wire going to a ground rod, even telephone wiring
or CATV wiring connected to that ground rod. (Remember, the earth is a
big resistor). KK9H, a fairly smart engineer who is one of my old
buddies in Chicago, intentionally uses the HVAC air ducts in his home as
a counterpoise for a 160M wire. At my last Chicago QTH, I used a big
wrought-iron fence running around the front of my lot as a counterpoise
on 160 and 80 for a Tee-vertical.

A connection to mother earth is important for only two reasons. First,
and most important, for lightning protection and electrical safety.
Second, for SOME receiving antennas, where the resistance of the ground
makes the antenna work, or where the loss of efficiency caused by adding
the resistance to an RX antenna doesn't matter.

SO -- let's stop using (or thinking about) the word "ground" in
conjunction with TX antennas, and in stead, talk (and think) of
counterpoise.

73, Jim K9YC

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Fred Moore-2

Re: Counterpoises and Grounding

Jim, lets stop talking about grounds totally when dealing with RF, it's
just a confusion factor when it comes to discussions. unless we are
talking about as NEC and others when they correctly call it a "Safety
Ground" or a "Grounding Conductor" and make sure that everyone
understands the difference.. most don't

discussions should be about

Safety Grounds, and grounding conductors 100% about 60 cycle and DC currents
common connection points 100% about how the above are connected
counterpoises, radiating elements: deals 100% with RF and antenna's

etc.. properly understanding each one and you won't be confused at all..

I also disagree with your statement

"First, and most important, for lightning protection and electrical safety."

The first and most important item is an electrical Safety Ground as it
protects people, they can't be replaced.
Second is lightening protection, as it typically protects equipment.
equipment can be replaced

They don't carry the same weighting factor.. as very few worldwide are
killed from lightning vs improper safety grounds.

most likely the only thing we don't agree on.. everything else you seem
spot on... Regards.. Fred

Fred Moore
email: [hidden email]
[hidden email]
phone: 321-217-8699

On 6/10/17 3:10 PM, Jim Brown wrote:

> On Sat,6/10/2017 11:40 AM, Stan GW3SRM wrote:
>> I note that the subject of counterpoises has been debated many times
>> in this
>> forum but I have not seen the subject of tuneable artificial grounds
>> discussed.
>
> Fundamental concepts like this are very well addressed in the classic
> references on antennas. Your use of the word "counterpoise" is
> precisely correct. Your use of the word "ground" is absolutely and
> totally WRONG.
>
> A connection to Mother Earth does NOT make a transmitting antenna work
> better. The earth is a big resistor. Shoving TX RF into it wastes TX
> power by warming worms.
>
> What IS needed, no matter where you operate, is a return for antenna
> current -- SOMETHING to act as the other half of the antenna. Antennas
> like a dipole inherently provide that; with an end fed antenna, we
> must supply that "other half," and the correct name for it is
> "counterpoise."
>
> Transmitters are designed to work into some defined load Z, usually 50
> ohms, but with some tolerance. That tolerance is often defined by the
> apparent SWR as measured at the transmitter. The function of an
> antenna tuner is to transform the Z at the transmitter end of the
> feedline to the Z that the transmitter want to see -- that is, the Z
> into which it will provide the most power, and do so without stressing
> the output transistors or tubes. The so-called "artificial grounds"
> provide the same function, but in a different way -- they vary the
> electrical length of the counterpoise so that the combination of the
> "intentional antenna" (the end fed wire) and the counterpoise make the
> Z at the transmitter as close as possible to 50 ohms. This allows the
> TX to put power into the antenna. That counterpoise, whatever it is,
> is PART OF THE ANTENNA. And that's true whether we CALL it "ground" or
> counterpoise.
>
> Another point. ALL end-fed antennas must put their return current
> SOMEWHERE. If we don't provide a "good" path (like a good
> counterpoise), mother nature will take over and put the current where
> SHE wants it to go, like anything attached to the chassis of the
> transmitter. This can be a coax shield, the power system protective
> earth (green wire), a wire going to a ground rod, even telephone
> wiring or CATV wiring connected to that ground rod. (Remember, the
> earth is a big resistor). KK9H, a fairly smart engineer who is one of
> my old buddies in Chicago, intentionally uses the HVAC air ducts in
> his home as a counterpoise for a 160M wire. At my last Chicago QTH, I
> used a big wrought-iron fence running around the front of my lot as a
> counterpoise on 160 and 80 for a Tee-vertical.
>
> A connection to mother earth is important for only two reasons. First,
> and most important, for lightning protection and electrical safety.
> Second, for SOME receiving antennas, where the resistance of the
> ground makes the antenna work, or where the loss of efficiency caused
> by adding the resistance to an RX antenna doesn't matter.
>
> SO -- let's stop using (or thinking about) the word "ground" in
> conjunction with TX antennas, and in stead, talk (and think) of
> counterpoise.
>
> 73, Jim K9YC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Jim Brown-10

Re: Counterpoises and Grounding

On Sat,6/10/2017 12:39 PM, Fred Moore wrote:
> Jim, lets stop talking about grounds totally when dealing with RF, it's
> just a confusion factor when it comes to discussions.

That's what I said.

> unless we are
> talking about as NEC and others when they correctly call it a "Safety
> Ground" or a "Grounding Conductor" and make sure that everyone
> understands the difference.. most don't
>
> discussions should be about
>
> Safety Grounds, and grounding conductors 100% about 60 cycle and DC currents
> common connection points 100% about how the above are connected
> counterpoises, radiating elements: deals 100% with RF and antenna's
>
> etc.. properly understanding each one and you won't be confused at all..

I've written extensively on this topic, and both that writing and
several slide shows are on my website. k9yc.com/publish/htm

>
> I also disagree with your statement
>
> "First, and most important, for lightning protection and electrical safety."
>
> The first and most important item is an electrical Safety Ground as it
> protects people, they can't be replaced.
> Second is lightening protection, as it typically protects equipment.
> equipment can be replaced
Again, I refer you to my website.
>
> They don't carry the same weighting factor.. as very few worldwide are
> killed from lightning vs improper safety grounds.
They are not different. Again, see my website. ALL grounds in a premise
MUST be bonded together. PERIOD. Power entry, Telco entry, CATV entry,
antennas, shack, etc. These connections must NEVER be separate or
independent of each other.

> most likely the only thing we don't agree on.. everything else you seem
> spot on...

I think what you view as disagreement is my failure to write well enough.

73, Jim K9YC
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Fred Moore-2

Re: Counterpoises and Grounding

Jim please accept my apologies, I didn't realize that since you have
written extensively on the subject and actually had a website that no
one else is allowed to comment without being chastised for contributions.

I have made myself a note to never reply to any conversation you are
currently or could possibly become involved in , as all authoritative
answers have already been provided on your web site.. and absolutely
nothing else ever need be discussed.

and again I must disagree with you. when you state that

"I think what you view as disagreement is my failure to write well enough."

you write extremely well, your condescending attitude comes through very
clear, to everyone.

Still wondering if I should remove all of my links on the internet, as I
now realize I only need one.

again, please accept my apologies.. I will make every attempt to make
sure it never happens again.

Fred Moore
email: [hidden email]
[hidden email]
phone: 321-217-8699

On 6/10/17 4:36 PM, Jim Brown wrote:

> On Sat,6/10/2017 12:39 PM, Fred Moore wrote:
>> Jim, lets stop talking about grounds totally when dealing with RF, it's
>> just a confusion factor when it comes to discussions.
>
> That's what I said.
>
>> unless we are
>> talking about as NEC and others when they correctly call it a "Safety
>> Ground" or a "Grounding Conductor" and make sure that everyone
>> understands the difference.. most don't
>>
>> discussions should be about
>>
>> Safety Grounds, and grounding conductors 100% about 60 cycle and DC
>> currents
>> common connection points 100% about how the above are connected
>> counterpoises, radiating elements: deals 100% with RF and antenna's
>>
>> etc.. properly understanding each one and you won't be confused at all..
>
> I've written extensively on this topic, and both that writing and
> several slide shows are on my website. k9yc.com/publish/htm
>
>>
>> I also disagree with your statement
>>
>> "First, and most important, for lightning protection and electrical
>> safety."
>>
>> The first and most important item is an electrical Safety Ground as it
>> protects people, they can't be replaced.
>> Second is lightening protection, as it typically protects equipment.
>> equipment can be replaced
> Again, I refer you to my website.
>>
>> They don't carry the same weighting factor.. as very few worldwide are
>> killed from lightning vs improper safety grounds.
> They are not different. Again, see my website. ALL grounds in a
> premise MUST be bonded together. PERIOD. Power entry, Telco entry,
> CATV entry, antennas, shack, etc. These connections must NEVER be
> separate or independent of each other.
>
>> most likely the only thing we don't agree on.. everything else you seem
>> spot on...
>
> I think what you view as disagreement is my failure to write well enough.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Michael Walker

Re: Counterpoises and Grounding

Jim sort of nailed it.

:)

Mike va3mw

On Sat, Jun 10, 2017 at 4:59 PM, Fred Moore <[hidden email]> wrote:

> Jim please accept my apologies, I didn't realize that since you have
> written extensively on the subject and actually had a website that no
> one else is allowed to comment without being chastised for contributions.
>
> I have made myself a note to never reply to any conversation you are
> currently or could possibly become involved in , as all authoritative
> answers have already been provided on your web site.. and absolutely
> nothing else ever need be discussed.
>
> and again I must disagree with you. when you state that
>
> "I think what you view as disagreement is my failure to write well enough."
>
> you write extremely well, your condescending attitude comes through very
> clear, to everyone.
>
> Still wondering if I should remove all of my links on the internet, as I
> now realize I only need one.
>
> again, please accept my apologies.. I will make every attempt to make
> sure it never happens again.
>
> Fred Moore
> email: [hidden email]
> [hidden email]
> phone: 321-217-8699
>
> On 6/10/17 4:36 PM, Jim Brown wrote:
> > On Sat,6/10/2017 12:39 PM, Fred Moore wrote:
> >> Jim, lets stop talking about grounds totally when dealing with RF, it's
> >> just a confusion factor when it comes to discussions.
> >
> > That's what I said.
> >
> >> unless we are
> >> talking about as NEC and others when they correctly call it a "Safety
> >> Ground" or a "Grounding Conductor" and make sure that everyone
> >> understands the difference.. most don't
> >>
> >> discussions should be about
> >>
> >> Safety Grounds, and grounding conductors 100% about 60 cycle and DC
> >> currents
> >> common connection points 100% about how the above are connected
> >> counterpoises, radiating elements: deals 100% with RF and antenna's
> >>
> >> etc.. properly understanding each one and you won't be confused at all..
> >
> > I've written extensively on this topic, and both that writing and
> > several slide shows are on my website. k9yc.com/publish/htm
> >
> >>
> >> I also disagree with your statement
> >>
> >> "First, and most important, for lightning protection and electrical
> >> safety."
> >>
> >> The first and most important item is an electrical Safety Ground as it
> >> protects people, they can't be replaced.
> >> Second is lightening protection, as it typically protects equipment.
> >> equipment can be replaced
> > Again, I refer you to my website.
> >>
> >> They don't carry the same weighting factor.. as very few worldwide are
> >> killed from lightning vs improper safety grounds.
> > They are not different. Again, see my website. ALL grounds in a
> > premise MUST be bonded together. PERIOD. Power entry, Telco entry,
> > CATV entry, antennas, shack, etc. These connections must NEVER be
> > separate or independent of each other.
> >
> >> most likely the only thing we don't agree on.. everything else you seem
> >> spot on...
> >
> > I think what you view as disagreement is my failure to write well enough.
> >
> > 73, Jim K9YC
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

riese-k3djc

Re: Counterpoises and Grounding

In reply to this post by Stan GW3SRM

Yep Bob K3DJC

On Sat, 10 Jun 2017 19:58:01 -0400 Michael Walker <[hidden email]>
writes:

> Jim sort of nailed it.
>
> :)
>
> Mike va3mw
>
> On Sat, Jun 10, 2017 at 4:59 PM, Fred Moore <[hidden email]> wrote:
>
> > Jim please accept my apologies, I didn't realize that since you
> have
> > written extensively on the subject and actually had a website that
> no
> > one else is allowed to comment without being chastised for
> contributions.
> >
> > I have made myself a note to never reply to any conversation you
> are
> > currently or could possibly become involved in , as all
> authoritative
> > answers have already been provided on your web site.. and
> absolutely
> > nothing else ever need be discussed.
> >
> > and again I must disagree with you. when you state that
> >
> > "I think what you view as disagreement is my failure to write well
> enough."
> >
> > you write extremely well, your condescending attitude comes
> through very
> > clear, to everyone.
> >
> > Still wondering if I should remove all of my links on the
> internet, as I
> > now realize I only need one.
> >
> > again, please accept my apologies.. I will make every attempt to
> make
> > sure it never happens again.
> >
> > Fred Moore
> > email: [hidden email]
> > [hidden email]
> > phone: 321-217-8699
> >
> > On 6/10/17 4:36 PM, Jim Brown wrote:
> > > On Sat,6/10/2017 12:39 PM, Fred Moore wrote:
> > >> Jim, lets stop talking about grounds totally when dealing with
> RF, it's
> > >> just a confusion factor when it comes to discussions.
> > >
> > > That's what I said.
> > >
> > >> unless we are
> > >> talking about as NEC and others when they correctly call it a
> "Safety
> > >> Ground" or a "Grounding Conductor" and make sure that everyone
> > >> understands the difference.. most don't
> > >>
> > >> discussions should be about
> > >>
> > >> Safety Grounds, and grounding conductors 100% about 60 cycle
> and DC
> > >> currents
> > >> common connection points 100% about how the above are
> connected
> > >> counterpoises, radiating elements: deals 100% with RF and
> antenna's
> > >>
> > >> etc.. properly understanding each one and you won't be confused
> at all..
> > >
> > > I've written extensively on this topic, and both that writing
> and
> > > several slide shows are on my website. k9yc.com/publish/htm
> > >
> > >>
> > >> I also disagree with your statement
> > >>
> > >> "First, and most important, for lightning protection and
> electrical
> > >> safety."
> > >>
> > >> The first and most important item is an electrical Safety
> Ground as it
> > >> protects people, they can't be replaced.
> > >> Second is lightening protection, as it typically protects
> equipment.
> > >> equipment can be replaced
> > > Again, I refer you to my website.
> > >>
> > >> They don't carry the same weighting factor.. as very few
> worldwide are
> > >> killed from lightning vs improper safety grounds.
> > > They are not different. Again, see my website. ALL grounds in a
> > > premise MUST be bonded together. PERIOD. Power entry, Telco
> entry,
> > > CATV entry, antennas, shack, etc. These connections must NEVER
> be
> > > separate or independent of each other.
> > >
> > >> most likely the only thing we don't agree on.. everything else
> you seem
> > >> spot on...
> > >
> > > I think what you view as disagreement is my failure to write
> well enough.
> > >
> > > 73, Jim K9YC
> > > ______________________________________________________________
> > > Elecraft mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > > Help: http://mailman.qth.net/mmfaq.htm
> > > Post: mailto:[hidden email]
> > >
> > > This list hosted by: http://www.qsl.net
> > > Please help support this email list:
> http://www.qsl.net/donate.html
> > > Message delivered to [hidden email]
> >
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list:
> http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Stan GW3SRM

Re: Counterpoises and Grounding

In reply to this post by Stan GW3SRM

I note the comments generated by this topic. I must admit the use of the
term 'tuneable artificial ground' generated some controversy but it is
widely used in both amateur and commercial literature. Perhaps 'tuneable
counterpoise' would have been better and the term 'artificial' is
superfluous. Safety earthing (grounding) is of course used for protection in
our 50Hz mains power distribution system, lightning protection etc. The
counterpoise is of course part of the antenna system described and I thought
antenna radiation and earth conductivity were well understood.

I regret that my submission should have created such heated comments.

Nuf said.

73 Stan GW3SRM

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Jim Ewing

Re: Counterpoises and Grounding

In reply to this post by Stan GW3SRM

As someone relatively unversed in grounding and counterpoises, this thread
has been very useful to me, so thanks to Fred and Jim.

That said, Jesse Colin Young advised us thusly back in the 60's,

Come on people now,
Smile on your brother
Everybody get together
Got to love one another
Right now.

Peace and 73,

Jim Ewing
N4TMM
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

David Cutter

Re: Counterpoises and Grounding

In reply to this post by Stan GW3SRM

Hello Stan

My note is a little off topic because I like to remove the counterpoise all
together by addressing the issue of common mode current.

I thought that, rather than getting embroiled with definitions, I would
offer something different. You don't say what bands you operate but your
crucial point is you are up in the sky so to speak and I've been there and
suffered accordingly.

*Until recently* no commercial antenna manufacturer had conquered the mighty
common mode current problem of the off-centre-fed dipole. Since you run QRP
you don't need anything big or heavy duty, you might consider the offerings
from Spiderbeam. They currently do a 40m version which covers all bands to
6m and your KX3 will handle any slight mis-match with ease. A friend of
mine ran one of these as a sloper out of his window using a KX3 and got
excellent results. No external tuning box or counterpoise is necessary,
it's all handled in the special dual choke balun. I understand they are
working on an 80m version. I have no commercial connection with the company.

If you prefer to build your own aerials, then you can see the website for
DJ0IP who in my opinion is now the world authority on these aerials having
done more research and *practical testing* than anyone. I doubt if that's
an exaggeration. On his website you will see how to make your own quite
inexpensively. There is also a lively and progressive forum dedicated to
the ocfd.

If you would like to know more, do get in touch.

73

David
G3UNA

ps I use a special version of the ocfd called the end-connected off centre
fed dipole.

----- Original Message -----
From: "Stan GW3SRM" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, June 10, 2017 7:40 PM
Subject: [Elecraft] Counterpoises and Grounding

>I note that the subject of counterpoises has been debated many times in
>this
> forum but I have not seen the subject of tuneable artificial grounds
> discussed. As no doubt many are aware, operating from a location remote
> from
> the ground has its problems in ensuring effective grounding, especially
> with
> end fed wire antennas. I have this problem as I operate from an upstairs
> shack. I have overcome the difficulty by using a tuneable counterpoise
> arrangement in conjunction with my end fed wire antenna. The EFW antenna
> is
> approximately 66ft (20m) long and the counterpoise wire 16ft (5m).
>
> Using my homebrew AGT and my KX3 is a simple process to tune for
> resonance.
> a) Tune to the desired frequency using the internal KX3 auto tuner. b)
> Tune
> for maximum current using the AGT meter (low power recommended for
> tuning).
> Repeat the process as necessary to obtain best match. Usually 1:0 or 1:1
> (KX3 reading). I only operate with 5 or 10 Watts. Apart from overcoming
> grounding problems you get a resonate grounding system not an
> approximately
> resonate one as used in most circumstances. This in my view, is a suitable
> compromise in overcoming difficult grounding conditions, although I do not
> advocate it in preference to an extensive grounding system where
> conditions
> permit. One point to note is that if an external power supply is used the
> output must be isolated from ground and suitable precautions taken against
> lighting strikes. Many designs for simple homebrew AFT projects are
> available on the web and MFJ also do one commercially. Obviously different
> or different multiple lengths of counterpoise wires can be used to get the
> best setup with your antenna.
>
>
>
> 73 Stan GW3SRM
>