144MHz Beacon IQ0OS upgraded

Last weekend we have installed a new transmitter for the IQ0OS/B beacon, now it sends the id on CW and PSK31.

Power output is about 5W on PSK31 and a bit more on CW.

QRG: 144.461


ANT: 2 x hentenna stacked for omnidirectional pattern, horizontal polarization

Any report on the ARI Ostia Webpage is very appreciated.


11 Responses to “144MHz Beacon IQ0OS upgraded”

  1. Tim Hendricks Says:

    Looking to build a hentenna in the same configuration, How well does it work? Any problems with it?
    Thanks Tim AK4YW

    • Hello Tim, after 3 years no problem at all. It was built with hydraulic chromated copper pipe (those of the sinks…). The two antennas have been tuned separately. The delay line for the phase shift and the impedance adapter has been made with coaxial cable.
      Here you can find some report and a coverage map of the beacon: http://goo.gl/KNdoau

  2. Tim Hendricks Says:

    I’ve only been a ham for a little over a year and I’m still learning and experimenting with making antennas. I have already made a single hentenna, but haven’t installed it yet. Then I saw the picture of your dual antenna. I wondered if they were simply attached at the same read point, but I can tell from your answer that I have a little more research to do before I try it. Thank you and 73. Tim AK4YW

  3. Can you tell us some details of the phasing line?

    • The antennas are feeded with 90deg of phase difference. After the coupler, one of the two coaxial cable is a quarter wave longer.

      • Thank you. What was the theory for the 90 degree feed offset? What would have been the problem with the two 50 ohms impedances in parallel at 0 degrees, other than impedance matching? I understand why to do this for a circular polarised antenna, but I would be interested to understand why you did it here. Very clever use of the hentenna! I use them on 40/80/160m

  4. Well, the theory is how you can couple two antennas to obtain more gain or, in this case, to modify the radiating diagram. The goal for the beacon was to obtain an antenna omnidirectional and horizontally polarized. If you feed directly the two hentennas, without transformer and 90° delay, you’ll have swr 2.0 and a non-omnidirectional lobe. I suggest to simulate it with MMANA or 4NEC2 to see what happens. Congrats for your BIG hentennas.

    • I tried making the antenna wider to get 100ohm, and then directly parallel two at the fedpoint. This worked very well. Very slight bend on an element to get better than 30dB RL.

  5. Vy good, by making the antenna at 100 Ohm you don’t need the impedance transformer, but in order to have an omnidirectional radiating diagram you need to feed them with 90° phase difference.
    Try with a simulator.

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