[Elecraft] My Experiences with EH antennas on 20 meters

[Charles Greene]

Ron and All,

The EH antenna really works, well.  It's efficiency, as an antenna, is on 
the order of 95%, as compared to about 75% for the full size 20 meter 
vertical with elevated radials I build last summer, and few percent for a 
short fat dipole the same size but just loaded with a loading coil because 
of the high losses in the loading coil.  On 20 meters, its beam width is on 
the order of a few degrees, concentrated near the horizontal.  As it needs 
no ground, its ground losses are very low. It doesn't need a return ground 
path that includes the lossy earth ground.  One of my EH antennas for 20, 
(I have four) has a bandwidth of 200 kHz, and it achieves this without 
resistance or other tricks.  On performance, the only way to fully evaluate 
an antenna is to do a one for one comparison with other antennas.  I have 
done this, and it is better in some directions than my G5RV and vice versa, 
as the G5RV is directional on 20 meters.  However, the EH antenna beats my 
relatively good Hustler 6BTV in gain consistently by 2 to 3 dB.   It does 
this by improved efficiency but mainly by a narrower beam width 
concentrated at a low angle.  On receive, it gives the most striking 
performance difference.  I used spectrogram to measure the noise floor and 
the signal level of PSK31 signals on 20 meters.  The noise floor is a full 
10 dB lower than my Hustler 6BTV, and 13 dB lower than my G5RV.  With a 
gain of 2 to 3 dB over the Hustler, the improvement in received signals is 
12 to 13 dB.  I was hearing signals on 20 I never knew were there with the 
other antennas.

Let me repeat this so I am not misunderstood.  The gain improvement of the 
EH antenna compared to the Hustler 6BTV is 12 to 13 dB only on receive 
signals and receive signals ONLY, and primarily because of a lower noise 
floor.

To put things in perspective, it is a good vertical antenna.  It is not a 
replacement for a good three element beam.  It doesn't even beat a good 
full wave loop, or most of the other multi-element gain arrays.  As far as 
I know, no one has used one in a gain array, but I don't know why this 
cannot be done.  It has to be high, some say 1/4 wave length, but I an 
working on this with some tests I am running, as I have had good results at 
3' high.  On 40 meters and below, the narrow beam width is actually a 
detriment, so the antenna is made shorter so the vertical beam width is 
wider at the expense of the gain of a narrower vertical beam width.  It is 
a single band antenna.  On 80 and 160, it's bandwidth is very narrow unless 
you want to use very large diameter (8" and 16") elements, or remotely tune 
it. It needs to be clear of other antennas, and like any antenna, it 
performs best when clear of obstructions.  I tried mine inside with poor 
results, but I may put my mailing tube version in my attic, as it can't 
stay outside during the rain. I am going to put one on a 10 ft pole on my 
sea wall in an out-of-the-main-view location where it should be a great 
performer for DX.  I installed my vertical with elevated radials on my sea 
wall last summer, but it did not meet the approval of the landscape 
inspector (XYL).

It seems to be a good antenna for portable use, as it is small on 40 
through 6, and can easily be hoisted up a mast or on a string over the limb 
of a tree.  It easily beats a shortened vertical, and it is easier to hoist 
than a full size dipole.  It's good for the guy with a small back yard.  I 
am going to try one for 160 next summer and mount it on my roof, as I don't 
have a 160 meter antenna or the room for an adequately performing one.  I 
am running some tests now and working with one of the designers, so we can 
more fully understand some of the performance characteristics of the antenna.

Others have had the same or better results.

GL on yours.  You can even buy an excellent kit at www.eh-antennas.com


73, Chas, W1CG
K2 #462