Elecraft

Long wire antennas MORE

Classic

List

Threaded

21 messages Options

Bill Levy

Long wire antennas MORE

Let me tell you what I observed with 700 feet of long wire.

QSB disappeared. What faded on one end was rocketing in on the other end.

I pointed the antenna at the USA from Kenya. There was nobody in the USA
that could not hear me. I ran 100 watts.

I had lobes going in every direction. I had huge gain forward. Check the
ARRL antenna book. It worked off the end and the front and the side.

It was the best wire antenna I ever used.

Best of all the elephants walked around my old Army Signal Corp 40 foot
poles bought new from Fair Radio Sales. That's right. The Elephants walked
around the poles. The sag in the middle was pretty deep but still taller
than an Elephant.

The longer the wire the more forward the gain. The better the lobes.
I never used a better wire and if I had to do it again I would do it again.

73 all, Bill

The science is simple. The more wire hanging out the more signal radiating.
______________________________________________________________
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]

Wes Stewart-2

Re: Long wire antennas MORE

As they say in real estate, location, location, location.

On 1/11/2018 9:41 PM, William Levy wrote:
> I pointed the antenna at the USA from Kenya. There was nobody in the USA
> that could not hear me.

______________________________________________________________
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 Gilbert

Re: Long wire antennas MORE

In reply to this post by Bill Levy

There is only a fixed amount of total energy contained in all the lobes
of an antenna. You almost definitely did get lots of lobes ... but you
also got lots of nulls that exactly offset all those lobes. You just
never heard the the hams that were in those nulls and they never heard
you. Whatever you gain in one or more directions is sacrificed in one
one or more other directions. This is basic physics.

More lobes is not necessarily better. In fact, taken to the extreme it
is self defeating because a very large number of lobes (assuming they
were somehow all of equal strength as you stated) begins to approximate
a unidirectional antenna with no azimuth gain in any direction.

Just for grins I modeled your 700 foot antenna in EZNEC+ and on 20m it
gave a maximum gain of about 9 dbi in a fairly narrow lobe at 16 degree
elevation in both directions along the axis of the wire. It also gave a
total of 36 other sharply narrow lobes arrayed symmetrically in all
other directions, each with a gain of about 6 dbi. Between each lobe
was a deep null of around minus 10 dbi. This was all at the same 16
degree elevation angle ... there were literally too many lobes to count
on the 3D pattern, with lots of lobes and nulls at every azimuth and
elevation angle.

A simple dipole at the same 40 foot height would have given similar gain
with a much broader lobe (both azimuth and elevation) in the two main
directions, but of course without the multiple smaller side lobes.
Three poles and two perpendicular dipoles would have given better
overall single band results ... the only advantage of the long wire
being that it gives a similar pattern along with similarly ugly match on
multiple bands.

Dave AB7E

On 1/11/2018 9:41 PM, William Levy wrote:

> Let me tell you what I observed with 700 feet of long wire.
>
> QSB disappeared. What faded on one end was rocketing in on the other end.
>
> I pointed the antenna at the USA from Kenya. There was nobody in the USA
> that could not hear me. I ran 100 watts.
>
> I had lobes going in every direction. I had huge gain forward. Check the
> ARRL antenna book. It worked off the end and the front and the side.
>
> It was the best wire antenna I ever used.
>
> Best of all the elephants walked around my old Army Signal Corp 40 foot
> poles bought new from Fair Radio Sales. That's right. The Elephants walked
> around the poles. The sag in the middle was pretty deep but still taller
> than an Elephant.
>
> The longer the wire the more forward the gain. The better the lobes.
> I never used a better wire and if I had to do it again I would do it again.
>
> 73 all, Bill
>
> The science is simple. The more wire hanging out the more signal radiating.
> ______________________________________________________________
> 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]
>

briancom

Re: Long wire antennas MORE

In reply to this post by Bill Levy

Bill,

The situation you had was essentially a point to point communications
setup. It worked well for you. Commercial installations long ago used
long wire antennas (including rhombics) pointed in specific directions
to assure good point to point communications. It isn't a "work all
directions" setup. The posting given by another reporting EZNEC results
is a true description of where the energy goes with a many wavelength
long wire.

This is not to say you can't work other directions. With appropriate
propagation and with your DX prefix, people would be workable off the
sides.

I think this tread started out with somebody wanting to have a portable
antenna for use in many locations. It is pretty clear that a point to
point antenna would not be appropriate for his application. Something
more omnidirectional would be.

73 de Brian/K3KO

On 1/12/2018 4:41 AM, William Levy wrote:

k6dgw

Re: Long wire antennas MORE

In reply to this post by Bill Levy

This could account for why my 2 wavelength Beverage never seemed to
perform well on 80 when we lived in Auburn CA. Elephants are very
uncommon in the foothills of the Sierra Nevada.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/11/2018 8:41 PM, William Levy wrote:

> Best of all the elephants walked around my old Army Signal Corp 40 foot
> poles bought new from Fair Radio Sales. That's right. The Elephants walked
> around the poles. The sag in the middle was pretty deep but still taller
> than an Elephant.
>
> The longer the wire the more forward the gain. The better the lobes.
> I never used a better wire and if I had to do it again I would do it again.
>
> 73 all, Bill
>
> The science is simple. The more wire hanging out the more signal radiating.
>

Dennis Moore

Re: Long wire antennas MORE

More common than you think :-) There are eight of them not far from my
place.

http://www.pawsweb.org/

Dennis NJ6G

On 1/12/2018 11:32, Fred Jensen wrote:
> This could account for why my 2 wavelength Beverage never seemed to
> perform well on 80 when we lived in Auburn CA. Elephants are very
> uncommon in the foothills of the Sierra Nevada.
>
> 73,
>
> Fred ["Skip"] K6DGW

______________________________________________________________
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]

k6dgw

Re: Long wire antennas MORE

Well, they never wandered out to Bowman Flats on Old Airport Road.
Apparently, I could have used them.

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 1/12/2018 11:37 AM, Dennis Moore wrote:

> More common than you think :-) There are eight of them not far from
> my place.
>
> http://www.pawsweb.org/
>
> Dennis NJ6G
>
> On 1/12/2018 11:32, Fred Jensen wrote:
>> This could account for why my 2 wavelength Beverage never seemed to
>> perform well on 80 when we lived in Auburn CA. Elephants are very
>> uncommon in the foothills of the Sierra Nevada.
>>
>> 73,
>>
>> Fred ["Skip"] K6DGW
>
> ______________________________________________________________
> 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]

Bill K9YEQ

Re: Long wire antennas MORE

In reply to this post by David Gilbert

Ron, love your comment. I use EFHW and it is amazing the confusion over how they work. Got to have a great transformer and a chosen antenna length and stick to it and perhaps a multiple that fits. My 160 EFHW is made for 1.900 and works well at 3.800 in certain directions on either band. I have do use a remote tuner for slight deviations and also compare two different dipoles to pick the best one to use. The 160 is a c shaped set in the trees. Insulated wire. Now to get it isolated with insulators. Next spring... too much cold weather and snow to deal with. :-)

73,
Bill
K9YEQ

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Ron D'Eau Claire
Sent: Friday, January 12, 2018 4:11 PM
To: [hidden email]
Subject: Re: [Elecraft] Long wire antennas MORE

A mistaken idea that many Hams get is that a wire antenna has no radiation in the "nulls". For example, a half-wave wire is often thought of as having no energy radiated off of its ends. There is LESS off the ends, but a real-world wire has some radiation in ALL directions as Dave notes. It's just stronger radiation in some directions.

A real long wire (many wavelengths) is easy to match since the longer a wire is, the smaller the impedance excursions across the RF spectrum. The hardest to match are wires a half wavelength (or less) long. However, most compact ATUs are limited in matching range based on simple physics. Their small size cannot tolerate the huge RF currents and voltages frequently encountered even at moderate power levels. There's a good reason why the old time "antenna tuners" (matching networks) were so huge. It's just a matter of basic physics. But today most of us use antennas that offer an feed point impedance limited to the range our ultra-fast, super-smart "automatic antenna tuners" can handle.

73, Ron AC7AC

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of David Gilbert
Sent: Thursday, January 11, 2018 11:41 PM
To: [hidden email]
Subject: Re: [Elecraft] Long wire antennas MORE

There is only a fixed amount of total energy contained in all the lobes of an antenna. You almost definitely did get lots of lobes ... but you also got lots of nulls that exactly offset all those lobes. You just never heard the the hams that were in those nulls and they never heard you. Whatever you gain in one or more directions is sacrificed in one one or more other directions. This is basic physics.

More lobes is not necessarily better. In fact, taken to the extreme it is self defeating because a very large number of lobes (assuming they were somehow all of equal strength as you stated) begins to approximate a unidirectional antenna with no azimuth gain in any direction.

Just for grins I modeled your 700 foot antenna in EZNEC+ and on 20m it gave a maximum gain of about 9 dbi in a fairly narrow lobe at 16 degree elevation in both directions along the axis of the wire. It also gave a total of 36 other sharply narrow lobes arrayed symmetrically in all other directions, each with a gain of about 6 dbi. Between each lobe was a deep null of around minus 10 dbi. This was all at the same 16 degree elevation angle ... there were literally too many lobes to count on the 3D pattern, with lots of lobes and nulls at every azimuth and elevation angle.

A simple dipole at the same 40 foot height would have given similar gain with a much broader lobe (both azimuth and elevation) in the two main directions, but of course without the multiple smaller side lobes. Three poles and two perpendicular dipoles would have given better overall single band results ... the only advantage of the long wire being that it gives a similar pattern along with similarly ugly match on multiple bands.

Dave AB7E

______________________________________________________________
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]

David Gilbert

Re: Long wire antennas MORE

In reply to this post by David Gilbert

All true. In fact, I was going to mention that for a real world antenna
there is usually some smoothing between lobes and nulls, especially when
there are lots of them involved. I left that out because I didn't want
to go overboard on my comments.

Another facet is that for any particular azimuth angle that has a null
at one elevation there might be a lobe at a different elevation angle.
3D plots of some antennas look very weird. I think a lot of yagis look
like that off the back ... deep null at a low angle but decent energy at
a higher angle. I live in Arizona and if I'm running the East Coast in
CQWPX I can still easily work California off the back.

73,
Dave AB7E

On 1/12/2018 3:11 PM, Ron D'Eau Claire wrote:

> A mistaken idea that many Hams get is that a wire antenna has no radiation in the "nulls". For example, a half-wave wire is often thought of as having no energy radiated off of its ends. There is LESS off the ends, but a real-world wire has some radiation in ALL directions as Dave notes. It's just stronger radiation in some directions.
>
> A real long wire (many wavelengths) is easy to match since the longer a wire is, the smaller the impedance excursions across the RF spectrum. The hardest to match are wires a half wavelength (or less) long. However, most compact ATUs are limited in matching range based on simple physics. Their small size cannot tolerate the huge RF currents and voltages frequently encountered even at moderate power levels. There's a good reason why the old time "antenna tuners" (matching networks) were so huge. It's just a matter of basic physics. But today most of us use antennas that offer an feed point impedance limited to the range our ultra-fast, super-smart "automatic antenna tuners" can handle.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of David Gilbert
> Sent: Thursday, January 11, 2018 11:41 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Long wire antennas MORE
>
>
> There is only a fixed amount of total energy contained in all the lobes of an antenna. You almost definitely did get lots of lobes ... but you also got lots of nulls that exactly offset all those lobes. You just never heard the the hams that were in those nulls and they never heard you. Whatever you gain in one or more directions is sacrificed in one one or more other directions. This is basic physics.
>
> More lobes is not necessarily better. In fact, taken to the extreme it is self defeating because a very large number of lobes (assuming they were somehow all of equal strength as you stated) begins to approximate a unidirectional antenna with no azimuth gain in any direction.
>
> Just for grins I modeled your 700 foot antenna in EZNEC+ and on 20m it gave a maximum gain of about 9 dbi in a fairly narrow lobe at 16 degree elevation in both directions along the axis of the wire. It also gave a total of 36 other sharply narrow lobes arrayed symmetrically in all other directions, each with a gain of about 6 dbi. Between each lobe was a deep null of around minus 10 dbi. This was all at the same 16 degree elevation angle ... there were literally too many lobes to count on the 3D pattern, with lots of lobes and nulls at every azimuth and elevation angle.
>
> A simple dipole at the same 40 foot height would have given similar gain with a much broader lobe (both azimuth and elevation) in the two main directions, but of course without the multiple smaller side lobes. Three poles and two perpendicular dipoles would have given better overall single band results ... the only advantage of the long wire being that it gives a similar pattern along with similarly ugly match on multiple bands.
>
> Dave AB7E
>
> ______________________________________________________________
> 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 Gilbert

Re: Long wire antennas MORE

In reply to this post by Bill K9YEQ

Well, since you brought up EFHW there is a relevant comment I've wanted
to make for a while.

An EFHW with a counterpoise wire (which everyone seems to claim is
important to have) is basically just an extreme version of an off-center
fed dipole. A half wave dipole has its lowest impedance at the center,
where the current is high and the voltage is low. As you move out away
from the center the current decreases and the voltage increases, which
is equivalent to saying that the impedance increases. As you get to the
end of the wire the current obviously goes to near zero except for
capacitive currents while the voltage goes very high ... meaning high
impedance. The "counterpoise" for an EFHW is merely an extension that
puts the feedpoint back toward the center where the impedance isn't
quite as high. And as with any dipole, it isn't critical how that
"counterpoise" is physically arrayed because the current there is small
so it doesn't affect the pattern much ... just as is the case with a
dipole with drooping ends.

I think if everyone viewed EFHW antennas as off-center-fed dipoles there
would be a lot less confusion about how they work. Just as with an
off-center fed dipole, an EFHW of the right length would have low
reactance and high impedance that could be properly matched with the
right transformer, and you'd need common mode chokes for both to keep
currents off the shield of the feedline. The two antennas are different
purely in terms, not in physical reality or in the radiation patterns
they produce.

73,
Dave AB7E

On 1/12/2018 4:33 PM, Bill Johnson wrote:

> Ron, love your comment. I use EFHW and it is amazing the confusion over how they work. Got to have a great transformer and a chosen antenna length and stick to it and perhaps a multiple that fits. My 160 EFHW is made for 1.900 and works well at 3.800 in certain directions on either band. I have do use a remote tuner for slight deviations and also compare two different dipoles to pick the best one to use. The 160 is a c shaped set in the trees. Insulated wire. Now to get it isolated with insulators. Next spring... too much cold weather and snow to deal with. :-)
>
> 73,
> Bill
> K9YEQ
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of Ron D'Eau Claire
> Sent: Friday, January 12, 2018 4:11 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Long wire antennas MORE
>
> A mistaken idea that many Hams get is that a wire antenna has no radiation in the "nulls". For example, a half-wave wire is often thought of as having no energy radiated off of its ends. There is LESS off the ends, but a real-world wire has some radiation in ALL directions as Dave notes. It's just stronger radiation in some directions.
>
> A real long wire (many wavelengths) is easy to match since the longer a wire is, the smaller the impedance excursions across the RF spectrum. The hardest to match are wires a half wavelength (or less) long. However, most compact ATUs are limited in matching range based on simple physics. Their small size cannot tolerate the huge RF currents and voltages frequently encountered even at moderate power levels. There's a good reason why the old time "antenna tuners" (matching networks) were so huge. It's just a matter of basic physics. But today most of us use antennas that offer an feed point impedance limited to the range our ultra-fast, super-smart "automatic antenna tuners" can handle.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of David Gilbert
> Sent: Thursday, January 11, 2018 11:41 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Long wire antennas MORE
>
>
> There is only a fixed amount of total energy contained in all the lobes of an antenna. You almost definitely did get lots of lobes ... but you also got lots of nulls that exactly offset all those lobes. You just never heard the the hams that were in those nulls and they never heard you. Whatever you gain in one or more directions is sacrificed in one one or more other directions. This is basic physics.
>
> More lobes is not necessarily better. In fact, taken to the extreme it is self defeating because a very large number of lobes (assuming they were somehow all of equal strength as you stated) begins to approximate a unidirectional antenna with no azimuth gain in any direction.
>
> Just for grins I modeled your 700 foot antenna in EZNEC+ and on 20m it gave a maximum gain of about 9 dbi in a fairly narrow lobe at 16 degree elevation in both directions along the axis of the wire. It also gave a total of 36 other sharply narrow lobes arrayed symmetrically in all other directions, each with a gain of about 6 dbi. Between each lobe was a deep null of around minus 10 dbi. This was all at the same 16 degree elevation angle ... there were literally too many lobes to count on the 3D pattern, with lots of lobes and nulls at every azimuth and elevation angle.
>
> A simple dipole at the same 40 foot height would have given similar gain with a much broader lobe (both azimuth and elevation) in the two main directions, but of course without the multiple smaller side lobes. Three poles and two perpendicular dipoles would have given better overall single band results ... the only advantage of the long wire being that it gives a similar pattern along with similarly ugly match on multiple bands.
>
> Dave AB7E
>
> ______________________________________________________________
> 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]
>

Don Wilhelm

Re: Long wire antennas MORE

Dave,

All information I have seen says that the counterpoise needed for an
EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.

If you make it longer than that, it becomes an offset center fed
antenna, longer than a halfwave, in other words, it is a random length
wire. Both the half wavelength wire and the counterpoise wire will radiate.

73,
Don W3FPR

On 1/12/2018 7:43 PM, David Gilbert wrote:

> Well, since you brought up EFHW there is a relevant comment I've wanted
> to make for a while.
>
> An EFHW with a counterpoise wire (which everyone seems to claim is
> important to have) is basically just an extreme version of an off-center
> fed dipole. A half wave dipole has its lowest impedance at the center,
> where the current is high and the voltage is low. As you move out away
> from the center the current decreases and the voltage increases, which
> is equivalent to saying that the impedance increases. As you get to the
> end of the wire the current obviously goes to near zero except for
> capacitive currents while the voltage goes very high ... meaning high
> impedance. The "counterpoise" for an EFHW is merely an extension that
> puts the feedpoint back toward the center where the impedance isn't
> quite as high. And as with any dipole, it isn't critical how that
> "counterpoise" is physically arrayed because the current there is small
> so it doesn't affect the pattern much ... just as is the case with a
> dipole with drooping ends.
>
> I think if everyone viewed EFHW antennas as off-center-fed dipoles there
> would be a lot less confusion about how they work.

K9MA

Re: Long wire antennas MORE

On 1/13/2018 07:44, Don Wilhelm wrote:
> All information I have seen says that the counterpoise needed for an
> EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.
>
> If you make it longer than that, it becomes an offset center fed
> antenna, longer than a halfwave, in other words, it is a random length
> wire. Both the half wavelength wire and the counterpoise wire will
> radiate.

True, and the longer the counterpoise, the more it will radiate, right
into the ground if it's just lying on the ground, so there's really no
point in a longer counterpoise for the EFHW.

One extreme case is the center-fed full wave, or "two half waves in
phase". It has the high feedpoint impedance of the EFHW (actually about
double) and has a pattern much like a dipole, but sharper. It has a
couple dB of gain over a dipole broadside but, of course, less gain in
other directions.

73,

Scott K9MA

--
Scott K9MA

[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]

Don Wilhelm

Re: Long wire antennas MORE

I once heard LB Cebik give a 'balloon' analogy of directional or gain
antennas.
He said the radiation pattern is like a balloon - you have to squeeze it
somewhere to get it to expand in another direction. There is no overall
gain, it just directs the radiation in one or more directions at the
expense of other directions.

73,
Don W3FPR

On 1/13/2018 11:41 AM, K9MA wrote:
>
> One extreme case is the center-fed full wave, or "two half waves in
> phase". It has the high feedpoint impedance of the EFHW (actually about
> double) and has a pattern much like a dipole, but sharper. It has a
> couple dB of gain over a dipole broadside but, of course, less gain in
> other directions.
______________________________________________________________
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 Gilbert

Re: EFHW vs Off-Center Fed Dipole

In reply to this post by Don Wilhelm

You can use whatever terms you want, but physically and electrically you
are turning the EFHW into an off-center fed dipole when you add the
"counterpoise" wire beyond the feedpoint. If you don't agree with that
you are merely adding to the confusion.

If you add 3.5 feet to a half wave 40 meter dipole it already is no
longer a true half wave anyway, and you might as well just feed the half
wave antenna 3.5 feet from one end.

Don't believe me? I modeled a half wave 40m dipole at 70 feet in
EZNEC+. At 67 feet long and fed at the center the feedpoint impedance
was 66 - j4 ohms. When I simply moved the feedpoint out to 3.5 feet
from one end (keeping the total length at 67 feet) the feedpoint
impedance became 1509 - j1202. I then added 3.5 feet to the antenna
(total of 70.5 feet) and fed it 3.5 feet from one end, which in your
world would be the EFHW with a 3.5 foot "counterpoise." The feedpoint
impedance changed to 3317 - j3115 ohms. Which do you think would be
easier to match (or easier to understand)? The 3D radiation pattern
was indistinguishable from each other in all three cases, of course.

It doesn't matter what you call it, but if you take a piece of wire and
feed it some distance from the end you now have an off-center fed dipole
... an extreme version possibly, but an off-center fed dipole nonetheless.

In my opinion, the term "counterpoise" is mostly a silly obfuscation.

Dave AB7E

On 1/13/2018 6:44 AM, Don Wilhelm wrote:

> Dave,
>
> All information I have seen says that the counterpoise needed for an
> EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.
>
> If you make it longer than that, it becomes an offset center fed
> antenna, longer than a halfwave, in other words, it is a random length
> wire. Both the half wavelength wire and the counterpoise wire will
> radiate.
>
> 73,
> Don W3FPR
>
> On 1/12/2018 7:43 PM, David Gilbert wrote:
>> Well, since you brought up EFHW there is a relevant comment I've
>> wanted to make for a while.
>>
>> An EFHW with a counterpoise wire (which everyone seems to claim is
>> important to have) is basically just an extreme version of an
>> off-center fed dipole. A half wave dipole has its lowest impedance
>> at the center, where the current is high and the voltage is low. As
>> you move out away from the center the current decreases and the
>> voltage increases, which is equivalent to saying that the impedance
>> increases. As you get to the end of the wire the current obviously
>> goes to near zero except for capacitive currents while the voltage
>> goes very high ... meaning high impedance. The "counterpoise" for an
>> EFHW is merely an extension that puts the feedpoint back toward the
>> center where the impedance isn't quite as high. And as with any
>> dipole, it isn't critical how that "counterpoise" is physically
>> arrayed because the current there is small so it doesn't affect the
>> pattern much ... just as is the case with a dipole with drooping ends.
>>
>> I think if everyone viewed EFHW antennas as off-center-fed dipoles
>> there would be a lot less confusion about how they work.
>

David Gilbert

Re: Long wire antennas MORE

In reply to this post by K9MA

You are both perpetuating the confusion here by pretending that these
are two different forms of antenna.

Of course the "counterpoise" will radiate. It will radiate energy
proportional to the current in it, and the longer its length the higher
the current will be. That's EXACTLY the same case as for an off-center
fed antenna ... they are the same thing. If you drop the end of an
off-center fed dipole too close to the ground it will waste energy in
the form of ground losses as well.

Calling it a counterpoise is a misnomer.

Dave AB7E

On 1/13/2018 9:41 AM, K9MA wrote:

> On 1/13/2018 07:44, Don Wilhelm wrote:
>> All information I have seen says that the counterpoise needed for an
>> EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.
>>
>> If you make it longer than that, it becomes an offset center fed
>> antenna, longer than a halfwave, in other words, it is a random
>> length wire. Both the half wavelength wire and the counterpoise wire
>> will radiate.
>
> True, and the longer the counterpoise, the more it will radiate, right
> into the ground if it's just lying on the ground, so there's really no
> point in a longer counterpoise for the EFHW.
>
> One extreme case is the center-fed full wave, or "two half waves in
> phase". It has the high feedpoint impedance of the EFHW (actually
> about double) and has a pattern much like a dipole, but sharper. It
> has a couple dB of gain over a dipole broadside but, of course, less
> gain in other directions.
>
> 73,
>
> Scott K9MA
>

Don Sanders

Re: Long wire antennas MORE

A
Rose by any other name is still a Rose.
Isn't Semantics fun?

On Sat, Jan 13, 2018 at 1:37 PM, David Gilbert <[hidden email]>
wrote:

>
>
> Calling it a counterpoise is a misnomer.
>
> Dave AB7E
>
>
>
>
>>

David Gilbert

Re: Long wire antennas MORE

"Isn't Semantics fun?"

True. ;)

Well, I rarely get hung up on the terms people use as long as we all
know what we mean when we call it whatever we are calling it. My
problem with the term "counterpoise" as applied to an EFHW antenna is
that it pretends that the extra length of wire is something other than a
way to shift the feedpoint toward off-center instead of off-end. In my
opinion it's misleading in terms of how the thing actually functions.

Dave AB7E

On 1/13/2018 12:45 PM, Don Sanders wrote:

>
> A
> Rose by any other name is still a Rose.
> Isn't Semantics fun?
>
>
> On Sat, Jan 13, 2018 at 1:37 PM, David Gilbert
> <[hidden email] <mailto:[hidden email]>> wrote:
>
>
>
> Calling it a counterpoise is a misnomer.
>
> Dave AB7E
>
>
>
>
>

Bill K9YEQ

Re: EFHW vs Off-Center Fed Dipole

In reply to this post by David Gilbert

The 3.5 ft aren't added. On the transformer, the low gnd side is where the .05' wire is added. It takes care of static and stray capacitance. I cannot remember the fellow who has written volumes about EFHW's and there is clearly a need for this. Absent a ground this works extremely well for portable end feds. The research was done in the field not on a model. There appears to be some misunderstanding, Dave. EFHW's use a wound transformer to match/reduce the impedance seen on the end of the wire. I had written about this in a previous post with very poor sentence structure, using "smart phone".

73,
Bill
K9YEQ

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of David Gilbert
Sent: Saturday, January 13, 2018 12:22 PM
To: [hidden email]
Subject: Re: [Elecraft] EFHW vs Off-Center Fed Dipole

You can use whatever terms you want, but physically and electrically you are turning the EFHW into an off-center fed dipole when you add the "counterpoise" wire beyond the feedpoint. If you don't agree with that you are merely adding to the confusion.

If you add 3.5 feet to a half wave 40 meter dipole it already is no longer a true half wave anyway, and you might as well just feed the half wave antenna 3.5 feet from one end.

Don't believe me? I modeled a half wave 40m dipole at 70 feet in
EZNEC+. At 67 feet long and fed at the center the feedpoint impedance
was 66 - j4 ohms. When I simply moved the feedpoint out to 3.5 feet from one end (keeping the total length at 67 feet) the feedpoint impedance became 1509 - j1202. I then added 3.5 feet to the antenna (total of 70.5 feet) and fed it 3.5 feet from one end, which in your world would be the EFHW with a 3.5 foot "counterpoise." The feedpoint impedance changed to 3317 - j3115 ohms. Which do you think would be easier to match (or easier to understand)? The 3D radiation pattern was indistinguishable from each other in all three cases, of course.

It doesn't matter what you call it, but if you take a piece of wire and feed it some distance from the end you now have an off-center fed dipole ... an extreme version possibly, but an off-center fed dipole nonetheless.

In my opinion, the term "counterpoise" is mostly a silly obfuscation.

Dave AB7E

On 1/13/2018 6:44 AM, Don Wilhelm wrote:

______________________________________________________________
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]

David Gilbert

Re: EFHW vs Off-Center Fed Dipole

Take a look at this link by AA6TB where he describes a counterpoise for
an EFHW.

http://www.aa5tb.com/efha.html (see Figure 5)

At least in his version, which I believe is the "standard" configuration
for one, the additional 0.05 wavelength wire is indeed added to the
length of the antenna. All it has done is move the secondary of the
transformer away from the end of the wire to get a lower impedance ...
just as I described below. I don't understand why this is so difficult
to grasp.

Unless the counterpoise you are talking about is connected somewhere
else in the system? Primary side of the transformer? Somewhere else?
If so I'd like to see a link to a drawing of it and I'd like to have
somebody explain how it supposedly works because it makes no sense to me
to put it there.

Otherwise, you are indeed adding length to the antenna on the far side
of the matching network ... just exactly as if it was an off-center fed
dipole.

Dave AB7E

On 1/13/2018 4:55 PM, Bill Johnson wrote:

> The 3.5 ft aren't added. On the transformer, the low gnd side is where the .05' wire is added. It takes care of static and stray capacitance. I cannot remember the fellow who has written volumes about EFHW's and there is clearly a need for this. Absent a ground this works extremely well for portable end feds. The research was done in the field not on a model. There appears to be some misunderstanding, Dave. EFHW's use a wound transformer to match/reduce the impedance seen on the end of the wire. I had written about this in a previous post with very poor sentence structure, using "smart phone".
>
> 73,
> Bill
> K9YEQ
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On Behalf Of David Gilbert
> Sent: Saturday, January 13, 2018 12:22 PM
> To: [hidden email]
> Subject: Re: [Elecraft] EFHW vs Off-Center Fed Dipole
>
>
>
> You can use whatever terms you want, but physically and electrically you are turning the EFHW into an off-center fed dipole when you add the "counterpoise" wire beyond the feedpoint. If you don't agree with that you are merely adding to the confusion.
>
> If you add 3.5 feet to a half wave 40 meter dipole it already is no longer a true half wave anyway, and you might as well just feed the half wave antenna 3.5 feet from one end.
>
> Don't believe me? I modeled a half wave 40m dipole at 70 feet in
> EZNEC+. At 67 feet long and fed at the center the feedpoint impedance
> was 66 - j4 ohms. When I simply moved the feedpoint out to 3.5 feet from one end (keeping the total length at 67 feet) the feedpoint impedance became 1509 - j1202. I then added 3.5 feet to the antenna (total of 70.5 feet) and fed it 3.5 feet from one end, which in your world would be the EFHW with a 3.5 foot "counterpoise." The feedpoint impedance changed to 3317 - j3115 ohms. Which do you think would be easier to match (or easier to understand)? The 3D radiation pattern was indistinguishable from each other in all three cases, of course.
>
> It doesn't matter what you call it, but if you take a piece of wire and feed it some distance from the end you now have an off-center fed dipole ... an extreme version possibly, but an off-center fed dipole nonetheless.
>
> In my opinion, the term "counterpoise" is mostly a silly obfuscation.
>
> Dave AB7E
>
>
>
> On 1/13/2018 6:44 AM, Don Wilhelm wrote:
>> Dave,
>>
>> All information I have seen says that the counterpoise needed for an
>> EFHW is 0.05 wavelength - at 40 meters, that is about 3.5 feet.
>>
>> If you make it longer than that, it becomes an offset center fed
>> antenna, longer than a halfwave, in other words, it is a random length
>> wire. Both the half wavelength wire and the counterpoise wire will
>> radiate.
>>
>> 73,
>> Don W3FPR
>>
>> On 1/12/2018 7:43 PM, David Gilbert wrote:
>>> Well, since you brought up EFHW there is a relevant comment I've
>>> wanted to make for a while.
>>>
>>> An EFHW with a counterpoise wire (which everyone seems to claim is
>>> important to have) is basically just an extreme version of an
>>> off-center fed dipole. A half wave dipole has its lowest impedance
>>> at the center, where the current is high and the voltage is low. As
>>> you move out away from the center the current decreases and the
>>> voltage increases, which is equivalent to saying that the impedance
>>> increases. As you get to the end of the wire the current obviously
>>> goes to near zero except for capacitive currents while the voltage
>>> goes very high ... meaning high impedance. The "counterpoise" for an
>>> EFHW is merely an extension that puts the feedpoint back toward the
>>> center where the impedance isn't quite as high. And as with any
>>> dipole, it isn't critical how that "counterpoise" is physically
>>> arrayed because the current there is small so it doesn't affect the
>>> pattern much ... just as is the case with a dipole with drooping ends.
>>>
>>> I think if everyone viewed EFHW antennas as off-center-fed dipoles
>>> there would be a lot less confusion about how they work.
> ______________________________________________________________
> 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]

Wes Stewart-2

Re: Long wire antennas MORE

In reply to this post by David Gilbert

I thought to add my two cents then I figured I ain't gonna smack this tar baby.;-)

On 1/13/2018 1:57 PM, David Gilbert wrote:

>
> "Isn't Semantics fun?"
>
> True. ;)
>
> Well, I rarely get hung up on the terms people use as long as we all know what
> we mean when we call it whatever we are calling it. My problem with the term
> "counterpoise" as applied to an EFHW antenna is that it pretends that the
> extra length of wire is something other than a way to shift the feedpoint
> toward off-center instead of off-end. In my opinion it's misleading in terms
> of how the thing actually functions.
>
> Dave AB7E