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416Re: RTrak-HAB antenna thoughts

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  • airsix73
    Sep 5, 2012
      Just wanted to follow up and let everyone know we pulled off a successful 1st balloon project. The RTrak-HAB performed well. In fact it survived a very hard landing. I didn't mess around with profile or frequency switching just to be safe.

      One thing I'm scratching my head over is that although I configured it for "WIDE2,1" it was not picked up by a single repeater. I used APRSISCE running on my laptop with a Verizon mobile wifi hotspot to act as an iGate from my chase-vehicle. That worked great, but I'm puzzled that it was ignored by the rest of the APRS community. There are plenty of repeaters around that certainly heard it.

      I ended up going with a vertical dipole which worked very well until roughly 100,000ft at which point we couldn't get out from under the doughnut and started missing packets. We were roughly 12 miles off to the side, but that was no longer enough distance. Our highest-altitude packet came in at 124k and change. Based on our rate of climb at that point and the time-stamp on the video we hit a bit over 126,000ft roughly 3 minutes later.

      Here is a bit of video from the last 1:30 before burst. Thanks for the help with antenna design!

      http://www.youtube.com/watch?v=GRqrnh_ySNs&feature=g-upl

      -Ben


      --- In RTrak@yahoogroups.com, "airsix73" <ben.messinger@...> wrote:
      >
      > Hello,
      > I'm preparing my first balloon launch and trying to decide on antennas for the mobile ground station as well as the balloon. I'm a new ham, and nervous about keeping a strong enough signal over 25-30 miles with just 350mw transmit power and random orientation. Suggestions?
      >
      > For best front-to-back ratio there are some really neat antenna designs (patch, bi-quad with reflector, yagi, 2 and 3 element quad) but they aren't very conducive to balloon work!
      >
      > For those of you who've done this before, what are your recommendations? I'm sure I'm over-thinking it, so I'd love to hear what others have done with success.
      >
      > Thanks!
      >
      > Ben
      >
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