It Really works!

There are many comments regarding the pros and cons of the theory as to how this antenna works, but very few reports from Hams who have tried to build it. I have now built two 40m versions on different types of PVC pipe, one black and one grey in colour. White PVC is unavailable locally in this size. Both use the simple floating link version as described by W0KPH. They were tuned using a MFJ-259B and the coil lengths were adjusted to give resonance at about 7.08MHz. The floating link (2 turn) spacings were adjusted to give an impedance of about 40-50 ohms. This meant shifting the floating link to about 1.2 inches below the main coil. The SWR at resonance was measured as about 1.2. The antenna was hung vertically in the roof space above the shack and connected to the transceiver (a Yaesu FT-920) using about 15ft of RG-58. Results showed that both versions gave suprisingly good results on receive, being about 6db down on an amplified magnetic loop and multiband vertical. The noise levels were low and comparable to the amplified magnetic loop antenna.On transmit, however, most of the power appeared to go into heating the coil, with very little of the energy being transmitted. Using 100w, tests with a local Ham about 2 miles away revealed signal reports of 5/9+20 using the vertical but only a dismal 3/4 using the EH antennas. Have I done something wrong, or is this also the experience of others?

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (MI5WJB @ June 07 2002,08:15)</td></tr><tr><td id="QUOTE">There are many comments regarding the pros and cons of the theory as to how this antenna works, but very few reports from Hams who have tried to build it. I have now built two 40m versions on different types of PVC pipe, one black and one grey in colour. White PVC is unavailable locally in this size. Both use the simple floating link version as described by W0KPH. They were tuned using a MFJ-259B and the coil lengths were adjusted to give resonance at about 7.08MHz. The floating link (2 turn) spacings were adjusted to give an impedance of about 40-50 ohms. This meant shifting the floating link to about 1.2 inches below the main coil. The SWR at resonance was measured as about 1.2. The antenna was hung vertically in the roof space above the shack and connected to the transceiver (a Yaesu FT-920) using about 15ft of RG-58. Results showed that both versions gave suprisingly good results on receive, being about 6db down on an amplified magnetic loop and multiband vertical. The noise levels were low and comparable to the amplified magnetic loop antenna.On transmit, however, most of the power appeared to go into heating the coil, with very little of the energy being transmitted. Using 100w, tests with a local Ham about 2 miles away revealed signal reports of 5/9+20 using the vertical but only a dismal 3/4 using the EH antennas. Have I done something wrong, or is this also the experience of others?[/QUOTE]<span id='postcolor'>
Hi,
ok very good.
Please remember that the antennas are reciprocal.
They have to work the same in Rx and Tx. the EH antenna is not an ecception. hence...I don't know wich wire gauge you used it.
Normally using a 12 awg wire and using 100 watts SSB you shouldn't notice any warm. of course if you transmit in AM or Psk31 or RTTY mode....is possible you notice some warming.
BUT your signal report on TX should be almost the same you had on RX. If look back on this forum, you will find many ham confirming this. The coil+link version is about 6 db under ..but on both tX and rx.
Please try to move your antenna on a different position especially don't so close to walls , ceiling included....
try on the table ..always keeping it vertical.
Let us know.
73 steve Ik5IIR

 

Many thanks for your advice, Stefano. I re-built the 85-40 meter version on grey PVC pipe using heavier wire and also corrected a wiring fault where I had forgotten to connect the bottom of the coil to the co-ax outer as well as the link. I was amazed with the results. On receive, signals were only about 1S unit down on my vertical, but with much less noise. On transmit(100w), a local ham and one 200 miles away confirmed signal reports also only 1S unit down on the vertical. Unfortunately I became too ambicious and tried it with 300w which roasted the PVC pipe. I will certainly be interested when a commercial version becomes available.

 

Hello Mb and other,

yes I got your point.
BUT...

we are speaking of 1 and 4" foot antenna long on 40 meters or 1 foot antenna long on 80 metrs....and so on....

What the EH antenna can do is produce the same signal of a full size vertical BUT using a full network version.
THE SIMPLE COIL+LINK VERSION is about 4 to 6 db under. neverthless is a good starting point to introduce the experimenters to this amazing new concept.

I am glad you can build short antennas performing 1 db under of the full size ones, but you should say us exactely the size of those antennas.
Nobody can change the Hertz antennas rules.
For sure you can't have 1 db under only , and still keep the antenna 1foot and 3 or 4" long on 40 or 80 meters

Then the eh antenna is showing several more new features, like a big S/N ratio on Rx, large bandwidth , no harmonic transmission ( and also no TVI ) and so on...

to answer some others questions, the EH antenna is available already in some models. In the Ted web site there are all indications.

have fun, steve IK5IIR

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (MattBeers @ June 12 2002,18:23)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (IK5IIR @ June 12 2002,03:31)</td></tr><tr><td id="QUOTE">Hello Mb and other,

yes I got your point.
BUT...

we are speaking of 1  and 4" foot antenna long on 40 meters or 1 foot antenna long on 80 metrs....and so on....

What the EH antenna can do is produce the same signal of a full size vertical BUT using  a full network version.
THE SIMPLE COIL+LINK VERSION is about 4 to 6 db under. neverthless is a good starting point to introduce the experimenters to this amazing new concept.

I am glad you can build short antennas performing 1 db under of the full size ones, but you should say us exactely the size of those antennas.
Nobody can change the Hertz antennas rules.
For sure you can't have 1 db under only , and still keep the antenna 1foot and 3 or 4" long on 40 or 80 meters

Then the eh antenna is showing several more new features, like a big S/N ratio on Rx, large bandwidth , no harmonic transmission ( and also no TVI ) and so on...

to answer some others questions, the EH antenna is available already in some models. In the Ted web site there are all indications.

have fun, steve IK5IIR[/QUOTE]<span id='postcolor'>
Stefano, this is the second time you have referenced 1 and 4" foot antennas. (you mean antennas which are 16 inches long, yes?).

But - your Euro website has photographs of antennas which are MUCH longer than this.  Why would you make them longer if they perform well at just over one foot?

I am also curious to hear your answer's to Doc's questions.  I would try to duplicate one of these antennas, except that W0KPH's website does not show how to measure when the tuning networks are adjusted right.  You and the other EH proponents have said that the tuning networks are there to provide correct phasing, not impedance match.  Therefore, one must reason, tuning for SWR is the wrong way, yet it is the way W0KPH's website says to do it.  How do you know you've got the phasing right?

Tell us how to do that and I'll build an antenna and sing your praises.  

Keep the information secret and you risk being figured as a charlatan.  

You lose nothing by divulging the data - the design is protected by patent, after all.

MB

Oh, yes, my "short" 40 meter antenna is four feet long.  A little shorter than the size of the one shown in the photograph on your webpage, laying on the table.[/QUOTE]<span id='postcolor'>
Hello Matt,
let me begin answering from the begin of your email.

Since the start of this long adventure we decided to reveal all. The previous CFA story told us the inventors were wrong to keep all those secrets.
Hence , from the beginning, we are revealing all to everybody.
The Ted Hart web site is a sort of reference for any need.

1) please look at the " build a 40 meters eh " document for any information regarding a perfect 7 mhz EH antenna
2) please look at " phasing an EH antenna " document to know any information about how this can be achieved.
3) please look at "almost book" document about all the theory of this new application

as you will see ,no secrets here, ok?

So, just to resume, built a 7 mhz antenna following all the instructions provided there and you will see what we mean for a good EH antenna. PLEASE, If you find some difficulties or you have some doubts, send to me an email. I will be happy to help you and everybody to fix everything. We keep our promises.It can be tricky....

about the thory I never told the EH antenna needs a phasing only. if you look back on these forum pages, I called it the " matching/phasing network " not only phasing.
we ,actually ,need to tune out the capacitive reactance AND produce the needed phase shift at the same time.
If you produce only the impedance matching and NOT the right phase shift the antenna will work as a normal short Hertz antenna with low performances.

One more note about your 4 foot verticals.
Matt I am sure and I believe your antennas can be quite efficient, but, again, you skipped to tell us exactely what kind of antennas you are talking about.
Do you have a "ground" or radials applied to them?
how important is the ground on your short antennas?
I am sure a lot.

The eh antennas DON'T need the ground....no land, no radials.

The pics on my site is showing some old revisions ehs.
very soon we will have a new and complete web site with a lot of pics, infos, and so on....when I refer to a 16 inches long antenna I am thinking of the radiant part of it.(the overall lenght of the two cylinders)
of course ,just under of it there is the network.
In the eh antenna the matching/phasing network is a tight part of the antenna, without of it, the eh antenna would be a normal short hertz antenna.
Anyway the overall lenght for a 7 mhz antenna (network included) is about 1 meter.....pole included.
In the EH antenna the cylinders lenght is NOT proportional to the antenna's performance, but only to the bandwidth.
we can build a 80 meters antenna having the same size of a 40 meters one, the only changing parameter is the BW.

I hope to have answered to any of your questions.
I am still available for any doubt you could have.
Sincerly steve IK5IIR

 

Hey this little antenna works very well for its small size. I built the 20 meter version, the larger one.
I used it in combination with my mobile rig, working as
a portable parked in front of my home, I worked a German, Italian, Ukranian, Maryland, Florida and a couple
of other stateside stations with 58 and 59 reports.
I was a skeptic, but these little guys do work, I plan to
build one for 40 meters and 15 also. Today I worked
a Florida station on 20 meters with a s9 +20db not
bad for a antenna 10 foot in the air and a total lengh
of 18 inches hi hi. Thanks: WA9KKN

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (wa9kkn @ June 14 2002,23:02)</td></tr><tr><td id="QUOTE">Hey this little antenna works very well for its small size. I built the 20 meter version, the larger one.
I used it in combination with my mobile rig, working as
a portable parked in front of my home, I worked a German, Italian, Ukranian, Maryland, Florida and a couple
of other stateside stations with 58 and 59 reports.
I was a skeptic, but these little guys do work, I plan to
build one for 40 meters and 15 also. Today I worked
a Florida station on 20 meters with a s9 +20db not
bad for a antenna 10 foot in the air and a total lengh
of 18 inches hi hi. Thanks: WA9KKN[/QUOTE]<span id='postcolor'>
Hello,
welcome in the EH antenna wondefull world !!!!

I am very happy of your note.
In this way ,I am sure, many others ham could believe to us.This antenna will be a revolution.

Please fell free to ask anything you want to optimize it.
Your results speak by their self.
All the best and 73's steve Ik5IIR

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (MattBeers @ June 14 2002,12:53)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (IK5IIR @ June 13 2002,09:57)</td></tr><tr><td id="QUOTE">Hello Matt,
let me begin answering from the begin of your email.

(some text politely deleted for brevity)

as you will see ,no secrets here, ok?

One more note about your 4 foot verticals.
Matt I am sure and I believe your antennas can be quite efficient, but, again, you skipped to tell us exactely what kind of antennas you are talking about.
Do you have a "ground" or radials applied to them?
how important is the ground on your short antennas?
I am sure a lot.

The eh antennas DON'T need the ground....no land, no radials.

I hope to have answered  to any of  your questions.
I am still available for any doubt you could have.
Sincerly steve IK5IIR[/QUOTE]<span id='postcolor'>
Hi Stefano, thanks for the reply.


1)  The "Build a 40 meters EH" document was interesting.  Adding some sketches and graphics would help a lot.  As it is, you have to switch back and forth between that document and Ted's web page a lot.

2)  The tuning procedure sounds very much like any other antenna.  You tune for lowest SWR and maximum FSR.  But I remain confused.  How does this tuning procedure guarantee that I got the phasing right?  How do I actually measure that I have the E and H fields in the right phase?  The website makes it very clear that this is critical, so I probably should know how to measure for it.

3)  I read the "almost book" a few times.  Many words, but few graphics make it a little difficult to diget.  The theory is not that important to me, I just want to know a good detailed instruction for how to build and tune and know for sure that I got an EH and not just a short dipole.

Yes, I think the website says plainly that the EH needs phasing and matching.  The tuning procedure, only guarantees matching because you are only measuring match and its consequent effect on radiation strength.  How do you measure that phase is correct?

My four foot antenna is a vertically-oriented dipole.  I like to work DX on 40 meters.  The radiation angle of a horizontal dipole is mainly too high, so I wanted a vertical.  But my ground is terrible, so I wanted to make the antenna less sensitive to ground.  A lot of articles talk about making a vertical with an elevated feedpoint as a way to reduce the dependence on ground conditions.

But a 40 meter vertical is big for my small yard, especially if it has to have radials.  I read a lot on the 160 meter enthusiast websites and books and decided to try a shortened vertical dipole.  I got a free antenna analyzer software to try modelling.   If I compare a quarter-wave vertical on poor ground, with a much shortened vertical dipole with the top of it at the same height the 1/4 wave would be at, the elevated vertical dipole gives more radiation at low angle.  The efficiency of the elevated vertical dipole can be a lot less than a horizontal dipole, even, and you still get more radiation at the right angles, because a horizontal dipole angle is too high for good DX, unless you can get it up very high.

I started with a half size dipole, about 33 feet long.  I made a matching network and measured the loss.  I figured out what part of the matching network made the loss and changed it until I got the measured losses lower.  

Then I cut the dipole size in half and re-adjusted the matching network.  Again I measured matching network losses and did what I had to for lower loss.

Eventually, I got to a kinda extreme Z and had to switch to a two-stage matching network to keep the losses low.

So I have the vertical dipole mounted now at 40 feet with no radials at all.  I have never tried radials or ground with the vertical dipole.  Maybe like you say it is sensitive to ground, but since I cannot make a good ground, I cannot make the experiment.

My matching network schematic looks the same as the "figure 3 L+T matching network" for the bi-cone, but I did not do anything to try to get a phase shift.  I tuned it exactly the way you describe, by tuning for low VSWR, then checking field strength.  Then I change a coil, retune for low VSWR and check the field strength again.  I assume I'm maximizing the Q of the elements in the network by doing this.

On DX contacts, the short vertical dipole (I make mine from copper water pipes with a fiberglass insulator between them) give a much better signal than the horizontal dipole.  On a recent JA contest, nobody could hear me when I use the horizontal dipole, but I made 20 QSOs in one hour with the short vertical dipole.  The horizontal dipole is now at 60 feet height, and the top of the vertical dipole is at 40 feet height.

I try to get some idea of signal strength by having distant stations record RX audio (with AGC on the receiver disabled).  I transmit with both antennas, at the same power.  The foreign station then turns the recorded audio into a .wav file and emails to me.  I play it back into an audio spectrum analyzer to see the different signals.

For the DX stations that have done this, the vertical dipole has delivered a signal about 12dB stronger than the horizontal dipole.  For stations that are closer than maybe 1000 miles, the horizontal dipole is giving a stronger signal by a few dB.

I don't think my antenna efficiency is as important as the main lobe radiation angle.

I have not built an EH, I know, but you asked some questions about the antennas I built.

I hope this answers your questions.

I would still like to hear how to tell when the phasing/matching network is making the right phase between E and H to make an antenna a EH.

Thanks,

MB[/QUOTE]<span id='postcolor'>
Hello Matt,
thanks very much for your prompt reply.

so for the questions regarding the EH antenna:

1) I got your doubts. Don't worry the inductances and capacitances indicated on my document were perfect to produce matching and phasing, the right ones.

as we know very well, each LC network can produce a phase shift on the current and produce a impedance transform also....that's all.You just need to have the right values.
We spent months to optimize those components, hence don't try to measure any phase shift, simply follow the instructions and you will have the antenna working.
Please follow all hints and kinks.

2) having the right values on the components you can tune it for the lowest SWR in the classical way , being sure you will get the proper phase shift also.

your antenna

congratulations it sounds like a very good project.
I got all and I am totally agree with you with all optimizations. Good job.

In the EH antenna , as you know, we designed a new application to get a very short antenna having the overall performances completely separated from the antenna's size. This is a new approach.

I will be very happy you could experiment with it . you are a real ham...as we say....a ham that loves experimenting, skilled, patient, interested on any news of this fantastic hobby. Matt you are welcome !!!

Please keep us informed about ....
AND IF for any reasons you will be in trouble....don't give up, but simply send me an email. I promise you to drive you toward a complete success.
have fun !!
steve IK5IIR

 

Hello to all, I am building a 40 meter "Can antenna" per W0KPH website,but due to busy-ness and work schedules, I hope to have it built in a week or so. I am also constructing an "easy" field strength meter and will include pictures of that as well. All the projects are fun, I just wish I had more time!!!!!!!!! But I sure do enjoy my children.
73' Jack KE0VH

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke0vh @ May 17 2002,09:13)</td></tr><tr><td id="QUOTE">Yes I know the basement is not the best place for a test and this weekend I plan on doing more properly mounted at about 12-15 feet above ground level.  BUT, LOOK how it performed in the basement!  That is what was so amazing!!!!!!  More later, I really look forward to alot of folks trying it out and letting W0KPH and myself know.  The reason for the obscurity is like anything else.  A lot of sceptical (reasonably so) folks, and only a handful of testing and research.  Plus, the proof is what really counts.    Good luck and let us know![/QUOTE]<span id='postcolor'>
They do work and they work well. Three weeks ago I read the articles about EH Antennas. Since that time I have constructed, one for 75m (4"dia. x 22"tall), one for 40m (4"dia. x 20"tall), one for 20m (2 1/2" dia. x 16"tall),
and one for 17m (2 1/2" dia. x 14"tall). The antennas were test at the N0KHQ Antenna Proving Grounds (back porch) all were mounted up at about 15'.
The EH Atennas is very well suited for persons living in areas where antenna restrictions apply. They work very well when installed in the attic also. They would be great for Back-Packers and military applications also.
I build all of the antennas I use and the EH, like my Sterba Curtain is a keeper.
You can build them better than you can buy them!

73 - N0KHQ - St. Louis

 

hello,
well done....! the steak of course..
congratulations , I am sure you will keep on your experiments improving them for sure.
I hope ,reading your notes, more and more experimenters will reach you in the successfull stories.
all the best from Italy
ciao 73's stefano IK5IIR

 

Hello,
I am wondering if there are some more news on EH experiments.
I know there are many of you having fun on this topic.
Please share with us your results.
I am receiving a lot of informations requests, hence this matter interest many of you. I am still available to give you any data .
C'mon friends...
73's Steve IK5IIR

 

Interesting subject. I too have spent a great deal of my life living in an apartment and trying to hide my antennas from the locals. Small antennas do work to some degree but their radiation efficiencies are governed by the following formulas taken from basic electromagnetism textbooks.

Radiation efficiency = 100% * Rr / (Rr+Rg+Rc), where

Rr = radiation resistance (ohms) ~ 197 D^2 / L^2,
Rg = ground resistance (significant for long wavelength),
Rc = loading coil resistance times cos^2 h,
D = antenna length,
L = RF wavelength, and
h = distance between loading coil center and feed point
expressed as an angle.
ALSO: ^ 2 denotes the square.

This may look complicated but the point to get here is that the radiation resistance drops off like a rock, Rr ~ L^2, as the antenna size gets smaller. Therefore, one must use wires of very low resistance in the coils to even keep the efficiency reasonable but when conditions are good even a watt of radiated signal can get out on HF. If you think 160m is hard to work with a "short antenna" just imagine how hard it would be to get a signal through 300 feet of salt water where you are forced to use wavelengths of 40km and longer. Our submarines are currently forced to drag wires that are miles in length to keep in contact with command centers while keeping their positions secret.

Very Short High Efficiency Superconducting Antennas

Ed AE4TM

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AE4TM @ Nov. 07 2002,11:03)</td></tr><tr><td id="QUOTE">Interesting subject. I too have spent a great deal of my life living in an apartment and trying to hide my antennas from the locals. Small antennas do work to some degree but their radiation efficiencies are governed by the following formulas taken from basic electromagnetism textbooks.

Radiation efficiency = 100% * Rr / (Rr+Rg+Rc), where

Rr = radiation resistance (ohms) ~ 197 D^2 / L^2,
Rg = ground resistance (significant for long wavelength),
Rc = loading coil resistance times cos^2 h,
D = antenna length,
L = RF wavelength, and
h = distance between loading coil center and feed point
     expressed as an angle.
ALSO: ^ 2 denotes the square.

This may look complicated but the point to get here is that the radiation resistance drops off like a rock, Rr ~ L^2, as the antenna size gets smaller. Therefore, one must use wires of very low resistance in the coils to even keep the efficiency reasonable but when conditions are good even a watt of radiated signal can get out on HF. If you think 160m is hard to work with a "short antenna" just imagine how hard it would be to get a signal through 300 feet of salt water where you are forced to use wavelengths of 40km and longer. Our submarines are currently forced to drag wires that are miles in length to keep in contact with command centers while keeping their positions secret.

Very Short High Efficiency Superconducting Antennas

Ed AE4TM[/QUOTE]<span id='postcolor'>
HI Ed,
Yes I am agree.

In fact the EH efficiency comes from a different way.
The eh is using a new concept to generate the EM wave. Is not a short loaded antenna like the common sense .

Here we are using a special matching /phasing network to align the E and H fields at the antenna. The far field is " brought " to the antenna starting at few inches from it.

This produce a high RR . the antenna is not using radials and ground connections , hence the efficiency approach 100%.

WE created another specific forum at yahoo.Please join us to:
http://groups.yahoo.com/group/eh-antenna/

I am sure you will find all the info you need.
73's steve IK5IIR