[HCDX] EWE antenna

["Michael Schnitzer" <mschnitzer@xxxxxxxxxxxx>]

Hello to all,

as a DXer one never is in the final development phase. Normally there always
is something to improve at the radio equipment. In this sense I was on the
search for an antenna, which first of all should have its max. performance
on the tropical bands, secondly should have a directional characteristic and
thirdly should lower the usual electric noise level on that frequency range.
The recent hits (K9AY, Beverage) didn' come into question. The K9AY is a
special MW antenna with moderate performance only on TB and the Beverage
exceeds somewhat over my property boundaries. However I found the wanted
antenna. The EWE antenna fulfills all criteria specified above in almost
optimal manner. This type of antenna was described first in the year 1995 by
Floyd Koontz, an American radio amateur. He constructed this antenna system
for ham purposes on 80 meters. Who wants to read the article, can do this
here:

http://home.iae.nl/users/reinc/scrapbk3.htm
http://www.arrl.org/tis/info/pdf/9502031.pdf
http://www.arrl.org/tis/info/pdf/9601032.pdf

Here also one can find appropriate schematic diagrams as well as the
respective radiation patterns for azimuth and elevation.

Construction principle:

In principle the EWE is an inverted U of approx. 8-9 m length with a height
of three meters over the ground. Those are dimensions, which fit in each
average garden. One end is earthed over a resistance of approx. 800 to 850
Ohms, the other end is attached over a 3:1 core balun to commercial coaxial
cable RG 58. In the Koontz article a 3:1 balun is recommended, which seems
to me a little bit incomprehensible. The output impedance of the antenna
amounts to 450 ohms, which would suggest  a 9:1 balun. But let's the antenna
theoreticians discuss this topic. Due to the lack of the required Amidon FT
50-43 core I just used my usual 9:1 baluns with good results. The main
reception direction is the end with the Balun and the coax cable. The zero
point is toward the terminal resistor.

East west combination:

It's a pure coincidence that I have three fruit trees in my garden exactly
in a series, exactly in the correct direction and exactly in the correct
distance! What does one want more? So I had the idea to build two EWEs, one
toward South America and one toward Indonesia.

Reception results:

After two days of test operation I can emphasize the most important point:
The EWE antenna produces almost quiet signals on the noisy tropical bands.
Let's begin with the performance on 60m. The signal strengths are
approximately 2-3 dB weaker compared to the 25m long wire and to the DX One.
That is to be neglected absolutely. If the station is situated in the
antenna main direction e.g. the east EWE, and one switches then to the west
EWE, the signal decreases approx. 20 dB. Due to the quietness of the signal
it's a real benefit to listen to a TB station for a longer time. The noisy
long wire has no chance here.

Due to the east west combination I yesterday could switch between RRI Jambi
and R San Miguel on 4925.2 at around 22.15 UTC without any problems. On 90m
the conditions are similar to those ones on 60m. The long wire produces here
higher signal levels than the other antennas. On 49m and 45m (out of band
Peruvians) the directional characteristic of the EWE is still apparent
likewise. On 45m however the DX One is unbeatable. On higher frequencies the
direction effect disappears, and long wire as well as DX One beat the EWE.

The medium wave:

Just so the EWE is applicable for MW-DX, especially in the version
structured by me. The signals generally are about 10-15 dB below the values
of long wire and DX One. The switching possibility forward/backwards is
ideal. Naturally this is nothing new  for K9AY and phaser owners.
Nevertheless here are some examples of the early evening yesterday:

531 kHz: The west EWE produced Switzerland as expected, on the east EWE
Faroe Islands came in very well, although the Faroe Islands aren't located
in the main reception direction of the antenna. Unusual good reception of
Faroe here in South Germany!

1017 kHz: On the west EWE came SWR. The east EWE suppressed the SWR
completely and a Turkish station became audible.

1053 kHz: On the east EWE Romania came in quite well, on the west
antennaTalk Radio UK. Separation almost completely.

1413 kHz: BBC Oman on the east EWE with O=4-5. Long wire and DX One produced
mud here only.

1458 kHz: Here one could switch between Tirana and Sunrise Radio.


Final reflections:

Who calls a garden its own as a DXer, should not use it for radish breeding
only! The EWE rather is the best antenna system for DXing on the tropical
bands, which one can still build under normal circumstances. All required
material is available for some DM only. Experienced Camp DXers have those
things in their store anyway. One open question remains however: Why I
didn't discover this fine antenna much earlier?


Good luck rebuilding the EWE

Michael Schnitzer  -  mschnitzer@xxxxxxxxxxxx
Receiver:  JRC NRD-525
Antennas: 25m longwire
                  DX-One Professional
                  EWE to Perú (260°)
                  EWE to Indonesia (80°)
Location:  Hassfurt, Germany

_______________________________________________
Hard-Core-DX mailing list
Hard-Core-DX@xxxxxxxxxxxxxxxx
http://www2.hard-core-dx.com/mailman/listinfo/hard-core-dx
http://www.hard-core-dx.com/
_______________________________________________

Copyright (c) 2000 Hard-Core-DX.com

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Text. A copy of the license is available in http://www.gnu.org/copyleft/fdl.txt.