I’ve seen a few spots in the past few weeks where the comments mentioned that the activator was using a Moxon antenna. The idea of being able to get some directional gain for events such as the upcoming Transatlantic event on Nov 4th is tempting. I may also be able to chase more contacts with a 10m Moxon than my currently extremely compromised 10m dipole I have setup in my office (in a ground floor apartment with no outdoor space).
If you have built a portable Moxon for HF operation, I would like to hear about what building materials you used to support the structure (both the rectangle itself and what you used as a mast). Most of what Google brings me uses materials like PVC pipes which seem too heavy for SOTA.
I have seen EA2BD’s very cool 20m vertical Moxon, which I may emulate. However I am a bit confused about why this is the only vertically polarized Moxon I have seen for HF operation. It seems easier to construct and deploy, so is there some downside to the vertical polarization I am not aware of?
Any other tips appreciated. If I do end up building one, it would be my first homemade antenna besides an extremely simple 10m dipole.
Hi Arthur!
Glad you enjoyed my take of the vertical Moxon.
Moxons are good antennas.
If I remember properly, the vertical Moxon had a bit less of gain compared to the regular horizontal design. But in the other hand you’d need a more complex support to get a horizontal Moxon up to the right height.
My 20m Moxon version was too bulky to be able to put that horizontal and that issue motivated me to turn it into Vertical. That way I required only a shorter length of rods (glass fiber) for the side elements and a portable version became then feasible.
To be honest, even the vertical 20m Moxon is too big. If you aim to get a low take off angle (DX) there are simpler ways to get that, like a fully vertical half wave (EFHW) , a Half square, or a Delta loop with the right orientation.
If I was to advise a Vertical Moxon my proposal would be better build a 15m or 10m band Moxon. I once participated in one of such Transatlantic events with a vertical 15m Moxon, and that one was maneagable and brought lots of NA in my log from EU.
The mast is the bottom 3 sections of a collapsible 10m mast, about 3m high, guyed by 3 cords attached to a ring supported on the top of the second section. On the top of the mast is a wooden hub that fits tightly on the pole. The hub has 4 holes drilled to accept replacement fibreglass tent poles. These are just the right length to curve up and are held in place by the tension of the rectangular wire harness that characterized the Moxon antenna. There is no support of the feed-point other than the tension of the wire, so the feed line must be light. I used 3m of RG-174, which has a loss of about 0.5 dB on 10m.
Ian
VE6IXD
Hi Arthur,
Something to consider when using a directional antenna such as a Moxon (good antenna, I have used them both portable and at home on 6 metres) is that if you are calling as the activator, some chasers will not hear you (or hear you at a lower strength) depending upon the general direction the antenna is pointing. If however from your summit location, most of your wanted calls are in a certain direction, then it’s fine and of course, if using it as a chaser and you can turn the antenna to get the strongest signal it’s a good choice.
I have tried the wire VP2E antenna in the past but while simple to put up, it had the disadvantage that when it needed to change transmission direction, it would physically have to be lowered, the elements relocated and the antenna raised again.
Ignacio, thank you for the additional information! Seeing you pull off a 20m Moxon certainly convinced me I should be able to pull off a smaller 10m build.
Ian, that setup looks pretty simple and I now have some “replacement” tent poles coming in the mail. Also glad to hear you are happy with the results with that amount of vertical height. Am I correct based on looking at that picture that you use the antenna without any balun? Good tip about the Coax, I’ll be using RG316 which I’m sure will be light enough.
Ed, Yes I know the Moxon has major nulls! This would not be for an everyday activation, but rather for special events like the recent Arizona 10 point madness or the upcoming Transatlantic event. The 40m EFHW will continue to be the daily driver. Using it as a chaser I’d be confined to my apartment office, which only has one useful takeoff direction anyway.
Hello Arthur,
You are correct that there is no balun, just a small piece of plastic as strain-relief as the wire harness is under tension and must be dimensionally stable. I was using the antenna with an FT-817ND, no amplifier, and the directionality was quite noticeable. I would call CQ and when that direction was worked out, rotate 60 degrees in azimuth and call again. I had to shuffle my seat around below the feed-point as the feed-line was as short as possible. It didn’t even touch the ground!.
The height of the antenna in wavelengths is not that bad - The pole is 3m, plus another couple of feet from the upcurved tent-poles, so perhaps 0.37 wavelengths.
I would be interested to hear if you decide to build a Moxon, I think they are great antennas, and the ability to reject noise coming from behind the antenna really helps to pick weak stations out from the noise.
Ian
VE6IXD
