Home > Daily News, Home Brew > A Quick Vertical 20m Moxon for Oceania DX Contest

A Quick Vertical 20m Moxon for Oceania DX Contest

The other day I decided I would take part in my first DX contest., the Oceania DX Contest. I wanted to work 20m (not my favorite band) with some sort of directional antenna, but it had to have a low take off angle and be easy to build and install. I decided to give a Moxon a try, but with a twist. I decided a vertical moxon would be the shot as it would be easier to make and very easy to hang from a tree branch. Once completed I could use it for DXpedition or portable work.

I searched on the net and found two references to a vertical moxon for 20m. One is here http://www.moxonantennaproject.com/ea2bd/EA2BD.htm

These while simple required more hardware than I had at my disposal, and I only had a day to go before the contest. So I replaced the mast with tree branch and a rope.

Initial testing with VK stations showed receive performance to be a couple of S points or worse down on the ZS6BKW antenna I normally use. I put this down to the height difference. The Moxon was only a metre off the ground at the bottom and 9m at the top whereas the ZS6BKW is 13 to 15m high.

It wasn’t until I used it in the contest that I found it superb on long haul DX. European stations via long path that I could not even hear on the ZS6BKW were S7 and S8 on the Moxon. I now have plans to give it a more permanent home on a long fibreglass mast.

73 David VK4MDX

Categories: Daily News, Home Brew
  1. Felix vk4fuq
    October 6, 2010 at 10:47 am

    G’day David, interesting stuff which closely echoes my experience with a vertically polarised Quad (and Delta) loop on 20 m. They are hopeless for interVK working but utterly superb on long haul DX. The reason is simply radiation angle, being very low, around 20 degrees whereas a horizontally polarised loop (‘the traditional way’) is much higher being about the same as a dipole at comparable ‘effective height, and much better for local working. http://www.mds975.co.uk/Content/amateur_radio_antennas_03.html Most are not aware of how radically changed a quad loop or one wavelength loop becomes when vertically polarised. Even the radiation pattern changes dramatically. It becomes mostly omnidirectional with nulls of only about 3 db. Interesting stuff. Regards, Felix vk4fuq.

    • olsenstours
      October 6, 2010 at 10:51 am

      Thanks for the comments Felix. Always good discussing antenna theory with you. I’ve been bush for 5 months so getting back in to it.

  1. October 14, 2010 at 9:27 pm

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