EH-ANTENNA : Conclusions
------------------------------------------------------
Felix Meyer HB9ABX  May 11th 05 / 13.6.05 / 8.7.05 / 6.8.05 / Update : 2.12.06


I was investigating this special EH-Antenna by collecting information
from HAMs who commented the antenna , based on their own experience.
In the following, I provide the obtained comments, and at the end I will add
my own conclusions, based on detailed study of the theory.
I want to thank all HAMs who contributed with their comments:
DL2SSR, DJ2ZS, DJ3JV, HB9EBV, WB2WIK
---------------------------------------------------------------

A radio friend who obtained the 40 m version EH-Antenna came to the
following result:
A DV 27 from CB radio is performing much better.
The difference between them are worlds ...


---------------------------------------------------------------------------------------------------------

It's not a joke: This mistery is is found since about 1990 in the radio world of
curious antennas, either as cross-field or EH-Antenna. But there is a  tremendous
difference between reality and theory, as the theory of this concept is beautiful,
beautifully wrong :-)

The fields cannot be "crossed" this way. This antenna consists of two small
antennas, of which one produces a strong E field, and the other a strong H field
in the near field. Both fields radiate and combine to an electromagnetic far field.
That's all.
The efficiency is that of a small antenna, that means: nothing special.
But "everything radiates" and the logarithmic scale in the form of db's make
the difference smaller.


-----------------------------------------------------------------------------------------------------------

An OM wrote to me, that he performed with another HAM a comparitive
test on 40m between a ground plane and an EH-Antenna ( EH installed
much higher than the grond plane antenna) over a distance of 10 km.
The result: S9 for ground plane, S4-5 for EH-antenna.
He named therefore the EH-antenna "an expensive dummy load".
> The performance of the EH should equal a conventional antenna.
Yes, I was reading that, but the EH surely is not a "wonder antenna".
I would be very interested in obtaining  experiences of other HAMs
if you obtain such information.

------------------------------------------------------------------------------------

I ordered an EH-antenna from WIMO and installed it in a good location.
Comparing the antenna against a dipole at the same location, the EH
generally gave 5 to 6 S-points less in transmission as well as in receiption.
After intensive tests I decided to pack the antenna nicely into its box
and to offer it for sale ...


-----------------------------------------------------------------------------

Tests during 6 weeks in 296 QSOs in SSB and CW on 20m,
comparing the performance with a 6 band GP (6BTV) over
short and long distances showed the following:
Generally 20 db less signal for the EH-antenna.

--------------------------------------------------------------------

Comment by HB9ABX :

Furthermore, I studied the theory of the EH-Antenna
as presented by the inventor
Ted Hart, W5QJR.
( http://www.eh-antenna.com/ )
Here I discovered, that all this theory is only based on a
wishful thinking. All this theory is pure imagination without
any scientific background or technical know how .
Complete nonsense.
(Update 8.July 05: Here I refer to the document "EH Antenna -
Definition, Ted Hart, 10-28-02)

The antenna is just an open resonant circuit, formed by the capacity
of the two "cans" and the coil between them, with a
matching section to adapt the feeding impedance.
At the same time, the feeding coax becomes an active radiator
which makes, that this combination is radiating more or less ...
The coax also radiates when a current balun is inserted, as the
electric field is very high and couples directly to the 1/2 wave cable.
 

20 dB attenuation corresponds to a power relation of 100:1,
or  99% power loss.
30 dB ( 5 S points) correspond to a power relation of 1000:1
what the tests showed.

I leave it up to you, if you want to call this construction
an antenna.

However, there are stories about this antenna, where
the performance comes close to the power of a dipole.
This may be explained by the fact, that the feeding line
acts as the main radiator.
Some installation instructions specify, that the feeding coax
shall hang free and that its length shall be half wavelength
or multiple of this.
In this case we end up with a half wave radiator,
fed by the EH.

So far my summary about the  EH-antenna.

With best 73's
Felix HB9ABX


Addition August 6th, 2005

Writing jokes  ...
--------------------
A Message from Karl, DJ4FO  "So far we only could read
the fantastic information from Felix. Is he not telling us
big jokes ? 73 from Karl,
DJ4FO" leads me to write you
my following experience with the EH Antenna:
(The EH Antenna is a short antenna with a length of
2% of the wavelenth, or shorter).
I would be very pleased to conduct a antenna test with
this type of antenna.
On the HAM RADIO fair in Friedrichshafen this year
I saw the motorhome from ARNO, the european manufacturer
of this antenna, which is sold by WIMO:
The EH antenna was mounted on the motorhome and I was
asking them, for which band the antenna serves.
They told me, it's the 40m antenna.
Then I told, that my station is just on the side and
I would like to make a radio test with their antenna.
Now they began to search all type of excuse, that no
test could be performed, at no day, at no time ...
Interesting, isn't it ?
By the way, WIMO specifies a gain of 0 to +2 dB of
the EH antenna !
And the user reports I received from my packet survey
indicated -10 to -20 dB, or even less.
Question: Are we not told a big joke by them ?
The manufacturer specificatons can be found at:


- http://www.eheuroantenna.com
- http://www.wimo.de/anteh_d.htm

If someone knows a user of the EH antenna close to Basel
I would be very grateful for obtainig this information, as
I would like to see him and conduct a antenna comparison
and would let you now the result here.

Update: 2.12.2006
Now the expected comparison with EH-antenna could
be performed on Novemver 30th.
Here are the results

Felix HB9ABX

BACK