K4QKY's initial impressions resulted in comparing the MOXON antenna with his 160 meter ladder line fed tuned horizontal loop at 65 feet. Click here for additional details about Don's 160 meter loop antenna including dimensions, height and radiation plots. The loop antenna is up at nearly twice the height of the MOXON. Furthermore, being several wave lengths long on 17 meters, the loop usually outperformed the MOXON during testing. Here is a sampling of testing results
Tests conducted 08/24/03 on 18.115MHZ with the MOXON pointed West to KW6LA in Southern California showed the loop to be 15 db better than the Moxon. The MOXON was subsequently rotated East to K2BLU in New Jersey who observed just the opposite with the MOXON being 15 db better than the loop. In both cases 15 - 20 db front to back ration was observed. KB5SOE who is located off the side of the beam was also on frequency and, as expected, observed little difference between the two antennas.
K6SGH "Steve" who is one of the project participants. He confirmed that the loop was about 10 db better than the MOXON.
K6VYX "Martin" who has also home brewed a MOXON of his own design. Our tests showed his MOXON to be outperforming his vertical by 15 db.
KH0AC "Len" on the island of Saipan in the Pacific who gave me a S7 report on the loop and could barely hear me on the MOXON.
WA6BEF through the W7DXX remote base in Massachusetts who reported the MOXON 2 s units better than the loop. This is the second instance where the MOXON favored an East coast contact by a substantial margin! In nearly all cases, the background noise is down 10 db from the loop which is most likely due to the MOXON's excellent front to back rejection.\
KD6WD John (who originally organized the MOXON Antenna Project) in California reported the MOXON to be 2 s units better than the loop. This was surprising since the MOXON had been lowered from 30 to 15 ft. pending an approaching storm.
KA1MUR on the East Coast observed the MOXON to be 2 s units better than the Loop and about 20 db front to back rejection.
KD6WD John in California reported the loop to be about a s unit stronger tonight than the MOXON which was just the opposite from last night (see above).
K6SGH Steve (one of the project participants) also in California who finished his MOXON installation earlier today. His is suspended beneath a tree for now. He reported the Loop to be 2 s units stronger than the MOXON. He also noted 25 db front to back rejection when the MOXON's heading was reversed.
W6LMJ in Florida (of the rear quarter of the MOXON) who reported the MOXON to be 25 db down from the loop.
W7USR in Washington who saw the loop up 1 s unit over the MOXON.
K4QKY'S overall conclusions:
The MOXON is performing up to expectations especially it's superior front to back rejection. This has the added benefit of making the antenna much quieter on receive than the loop.
Admittedly, in many instances during testing, the 160 meter ladder line fed tuned loop has outperformed the MOXON. Perhaps, this is to be expected given that the loop is over twice the height and has the benefit of greater aperture/capture area.
The MOXON's performance and resonant frequency seems to be somewhat sensitive to height above ground. In some instances the antenna has performed better at 15 ft. than at 30 ft.
The MOXON is an excellent alternative for hams who enjoy 17 meters but have resorted to dipoles due to cost/space constraints. It is also a great antenna for portable use.
Note: K4QKY lives in Western Kentucky
AB0YY "Ron" provided
the following assessment 08/27/03:
"Since I put up the MOXON in place of the folded x-beam, stations that remember the signal from the x- beam are telling me the moxon is by far the better antenna. I have seen on the average of 2 to 3 s units improvement. I added the garden stake to support the center of the reflector, great idea. My coax is fed thru 1/2 in pvc pipe to the feed point and wire wrapped. I will be putting a balun on because I am slightly getting into the TV. I was doing some work on the computer late the other night about midnight and kept hearing faint voices and whistles at 18.140. I had the moxon pointed SW and put out a QRZ. V73B, Buzz came back to me and gave me a 5-9. It may be magic but I am hearing a lot more with this moxon. Last night I called KH6BB, working from the USS Missouri in Pearl Harbor. Ned said my signal was extremely strong compared to other stations he had been working. I just finished a QSO with Frank in California, K6KS. He mentioned several times about my signal. He even told me he could hear me without an antenna hooked up. I must be in a good location for the angle of take off. One thing I have seen, signals from Tasmania are not as strong as the x-beam. I will observe a little longer. Bad news is, my center support is drooping from the weight of the poles. I got a bad piece of plywood from the wire spool end. I am now looking for a 18 in diameter fiberglass hub. don't know if I want to use the 18 in diameter aluminum plate I had made up. My goal is on a 50' pushup, stacked MOXONs, 20m at 30ft and the 17m at 40ft. By the way, I can't see whereby lifting the sag in the reflector helped. If so by very little. Really enjoy this and everyone I talk to is very interested. This project is growing!"
Note: AB0YY lives in Topeka, Kansas
KD6WD "John", having gone thru thousands of feet of wire building antennas since becoming a ham, offered the following comments 09/11/03:
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Out of all the wire beam designs the Moxon is the easiest to build and rotate.
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The Moxon is compact, economical, and a very good performer. Except for being a mono band antenna, it outperforms vertical antennas at the same height. Working DX on his "name brand vertical" from California into Europe was difficult for John even when running 400 watts. With the Moxon at about 20 or 22 feet, he has worked more European stations on 100 watts using the Moxon, than anytime the previous 8 years while running power using a vertical antenna.
John has been comparing the Moxon to his 2 element cubical quad. The top of the quad is at 50 feet with the Moxon on a pushup pole at 20-22 feet. The Moxon is being fed with RG58 and the Quad with RG 213. Although signals varied, the Cubical quad heard the stations by almost a full S unit better in some cases. What was surprising was that in many cases there was only 1/4 to 1/2 S unit difference on receive. In about 7% of the cases there was absolutely no difference in the received signal level. The further away the DX station was, the less difference there was in received signal level. The signal reports returned either were identical or 1/2 s unit better on the Quad.
John doesn't plan on giving up his quad. Besides, the quad has six bands on it and works very well. John is planning another Moxon... this time for 40 meters on a longer mast from his 36 foot tower. Since the 17 meter Moxon works well at 20 feet, John feels that a 40 meter wire version should work well at 45 or 50 feet.
Thanks to Allen Baker, KG4JJH, who wrote an article for the May, 2003 issue of QST magazine entitled The Black Widow--A Portable 15 Meter Beam..., John elected to use fiberglass crappie poles for this project. John feels that this was the right decision as it helped get rid of the dacron rope support structure that were used with his earlier pvc sprinkler pipe prototype. Use of these poles also dropped the weight to less than six pounds, reduced the total wind area to 2 1/2 feet, and allowed use of an economical rotor ($69.95 new or $25.00-used). Since the MOXON works so well at 20 feet, the mast can be a single 1 1/4 inch 20 ft 6061-t6 aluminum schedule 40 pipe properly guyed. Even on mornings with very heavy wind gusts, the crappie poles kept the wire on the MOXON tight even though the RS pushup mast flexed about 6 or 8 inches.
John lives in Florida.
KF4EFH "Kevin" is testing his MOXON at 30 feet against his A-99 vertical antenna . Kevin says that receive seems to be 3-7 db increase over the Solarcon vertical A-99 http://www.universal-radio.com/catalog/hamants/1001.html . One Station that he could not hear at all on the vertical was 5-7 on the Moxon. Reports from several European stations placed the Moxon at least 3+ db over the vertical including Slovenia "S59PC", Beirut Lebanon "OD5NH", Hungary "HA5OG", Bulgaria "LZ2KV" and U.K "G2BKZ".
Note: KF4EFH lives in Western Kentucky
K6SGH "Steve" is
testing his MOXON at 40 feet suspended beneath a tree. After using the antenna for a week, he reports that
he continues to be impressed with it's overall performance. "For such a small
antenna, two simple wires, it is really amazing." Steve says that he was
listening to one of the other project participants "Ron" talk to a ham in
California. During the conversation, he rotated his MOXON 360 degrees noting
the front to back and side rejection to be equally amazing at least 30db. There
was one point, off the back corners, where the rejection was even greater.
Steve spent several evenings facing his MOXON in unusual directions and
found that all he heard were signals from those directions. "That is what a
beam is all about. fantastic!"
On 09/14/03
Steve added 20 meter elements to the antenna in the same way as his 17 meter
element except the feed point was configured with a 450 ohm jumper connection as
shown here.
Steve tends to believe that separate feed lines to each element will produce the
best results. However, since he did not have another yagi balun and the 1:1
balun he did have was way too heavy to put on the antenna, he elected to
try the following:
1. Connected a piece of 50 ohm coax from the feed point of the 17 meter antenna to the 20 meter element. He then hoisted it up and tested it and found a >5:1 match on both bands which was unacceptable so he immediately brought it down.
2. Next, he connected a piece of 450 ladder line from the 17 meter feed point to the 20 meter element as shown here. This resulted in a 1:1.2 match on 17 meters and 2.5:1 on 20. For now, Steve uses his tuner on 20.
Steve tested the antenna
with K4QKY "Don" on 17 meters. Don and Steve both believe that front to
back rejection on 17 meters is still good. Signals were up and down but Steve
believes that the 17 meter element is working as well it did when it was a
monobander.
Steve then tested the 20 meter element with AB0YY "RON" and although no
testing was accomplished for front to back rejection, it seemed to be working
ok.
More testing will follow including separately feeding each element.
Note: K6SGH lives in Southern California
K6VYX "Martin" is testing his MOXON (with bamboo spreaders) from a push-up mast. Martin reports that he loves his MOXON and has worked Poland with his 100 watt rig and got a signal report of 57 to 59. Martin is testing his MOXON against a Gap vertical and routinely notes the MOXON to be 5 to 6 S units better than his vertical! Marin will be soon be replacing his bamboo spreaders with fiberglass Crappie fishing poles that all of the other project participants are using.
Note: K6VYX also lives in Southern California
N0KHQ "John" has been testing his Coaxial MOXON on a daily basis comparing it against his Sterba Curtain as a reference. He feels that this is a somewhat unfair test but the Sterba is the only other antenna that he has. The Sterba and the Moxon (at 30') seem to compare equally on receive.....the jury is still out on transmit.
The Moxon front to back appears to be good. Because John is feeding the front element and rear element 270 Degrees out of phase, he believes the gain of the antenna to be somewhere around 8db (not to be confused with dbi). All testing is being done with 100 watts output.
As we move into the winter months more accurate testing will be done and performance updates will be added to this page as they become available.
A Coaxial Moxon is soon to be published on the Hamuniverse.Com website, but will not include the phasing or feeding as discussed here.
Note: N0KHQ lives in Missouri
...A testimonial from Rich "KY6R" who, after a visit to this website, was prompted to build his own MOXON. Rich's email is rholoch@comcast.net .
KA4SDU "Hal", maryannehal@hotmail.com also designed and built his MOXON with bamboo but in a far different physical configuration. You can learn more about the performance of Hal's unique MOXON design by clicking here.
