THE EH-ANTENNA (40m Version)
A test of a 40m EH-ANTENNA
Like its cousin, the Cross Field Antenna (CFA), the EH-ANETNNA is one of the most controversal antennas of our times. I followed the engineering discussions, disputes, and wars on this antenna for a long time.
As a non-engineer, one wonders how two people with similar training and achidemic degree can differ so radically in opinion of the same antenna.
Like always, I am more interested in how well an antenna performs than in why it performs.
I decided to find out how this antenna performs, the only way I know how:
Install the antenna and compare it to other known antennas.
GOOD VS. BAD ?
Just what is a good antenna? We have to agree this point before we can call any antenna good or bad.
We all agree that a 5 element monoband beam on a 100 foot tower is a good antenna. Unfortunately very few of us will ever have the possibility to have this... and even if we can, it probably will not be for 40m or below.
In my opinion, an antenna is good if it meets the following reqirements:
- you are able to erect and use it at your QTH
- it enables you to make contacts on a band you were previously not QRV on
- you can find no other antenna of that size, price, or simplicity that works better
- you are unable to install a known better antenna due to cost, looks, neighbors, etc.
Notice none of these were really technical reasons!
There were no claims to being the highest performing, or anything else.
These are real life reasons for the choices most of us have to make when selecting an antenna.
AND, it should be clear that "good or bad" will depend on environmental, not just technical characteristics!
A good antenna does not have to be the best antenna in all cases.
It only needs to be the best antenna one can deploy
under certain restrained circumstances
to qualify as a good antenna!
In the case of the EH-ANTENNA, I see its strength in the low bands (160/80/40m).
REASON: On the higher bands, I feel most people would be able to deploy something better, whereas on the low bands, this may be the only reasonable way of getting on the air.
HOW I TEST:
- Since the beginning of time (my time), I have used an openwire fed 80m dipole for my low bands antenna. I know quite well how it performs.
- Since 1992 I have used an openwire fed, short Vertical Dipole for the high bands whenever I had no beam available. I also used it as my primary high bands antenna for portable work.
- As a result, I know both of thes antennas well and use them to compare unknown antennas to.
- Most tests are receive-only but with a few QSOs as sanity check.
- I use the S-Meter of a Ten-Tec transceiver which is about as accurate as any transceiver is.
HOW I TEST 40 METERS:
40 meters is actually 3 bands in one. It has different propagation characteristics at different time periods of the day. There are 4 different time periods in the day: Daytime, Night time, Dawn, & Dusk.
As in the name, 40m propagation is as different as night and day when used during the night or day.
Curious, it is very similar at dusk to its propagation at dawn, and together I call thes two the third time period of the day that we should focus on.
THEREFORE, I have taken care to make lots of tests in each of these three time periods.
I know many of you are impatient and only interested in the final results.
I am not going to disclose them here. They are described in detail in the PDF file below.
You will find them at the conclusion of the test.
If at this point I just said good, or bad, or whatever, there would potentially be cause to question my results. You have to view my results in light of the environment surrounding the test.
I have taken great care to outline in detail the QTH and the conditions in which the test was conducted, and shown about a hundred recorded results which lead to my conclusion.
But if you still can't wait, here's a SNEAK PREVIEW:
According to the critiques, if this antenna works at all, it is because the coax is radiating, not because of the efficiency of the antenna.
Accordint to me, unless there are any negative side affects, then I don't really care. I can insert a good RF choke in the coax at the point I wish it to stop radiating. In fact I did insert a Radio Works T4 in the coax, just before it entered the house.
When I view the home QTH and antennas of some of the experts criticizing the loudest, it's no wonder they consider this to be a poor antenna. They have large towers and long wires.
Beauty is in the eyes of the beholder.
If the beholder happens to live on the 10th floor of an apartment building in the middle of the city, he is unable to run any wires outdoors, but he can install an EH-ANTENNA on his balcony and get on the air. How does that compare to . . . nothing at all?
Under these circumstances I'd say it is one hell of a GREAT antenna!
Almost A Test EH-Antenna.pdf
PDF-Dokument [237.1 KB]
THE OTHER SIDE OF THE STORY
"The EH-ANTENNA does not work. PERIOD!"
As I said above, a lot of really good engineers have concluded that this antenna cannot possibly work.
One OM, "ADAM" (call sign I have forgotten), put out an extended effort to evaluate this antenna, comparing it to a good ground plane. He chose an excellent desert location with nothing around for miles that could skew his measurements.
Adam used very professional test equipment and took precise measurements.
When you see the professionality with which Adam conducted his test, you will understand why I called mine "Almost a Test".
He reached a conclusion that the EH-ANTENNA was 12 to 28 dB WORSE than the ground plane, all the time.
You can download his entire test report below:
PDF-Dokument [300.2 KB]
SO WHAT IS THE REAL TRUTH ABOUT THIS ANTENNA?
I'll be honest: I don't know.
My personal test results using a commercially built EH-ANTENNA contradict the claims and results of several engineers whom I highly respect.
I opted to test a commercially built antenna, rather than build my own, because I wanted to rule out any negative factor which I might accidently inject into a home-brew antenna.
Adam was loaned an antenna from Ted Hart, the inventer of the EH-ANTENNA.
According to Ted, Adam's test was not valid because he used a low pass filter between the transmitter and the antenna. This introcuced an phase shift which distorted the E/H phasing.
Sorry guys, I am not smart enough to judge this!
But I do know how to read an S-Meter and copy a signal report given to me on the band.
People on both sides of this arguement claim victory.
My Opinion: If it feels good, do it!
I no longer have an EH-ANTENNA because I have been lucky enough to live in a QTH where I can put up better antennas. However I would not hesitate for a heartbeat to buy and errect a commercial EH-ANTENNA, should I ever find myself living in an appartment building with jast a balcony to mount my antenna on.
In another test, I will report on my experience with the 80m version of the EH-ANTENNA. The results were simular to my test of the 40m antenna. The antenna was definitely NOT an Ass-Kicker antenna, but it definitely did enable me to work the world on 80m with an antenna with a tiny footprint.
Do your own due dilligence!