17 April 2009

First attempts at AO-51

I had wanted to check how easy are today HAM sats for a long time, until I decided to give them a go few days ago. AO-51 looked like a good candidate, especially now that with FT-817 I can receive UHF with a simple setup.

I prepared as follows:
  • calculated next passes on the AMSAT website according to my location,
  • picked a comfortable pass, that would fly high over my head (strangely enough, at the time I'm driving to the office!)
  • prepared a 1/4 wave vertical antenna for the magmount car base
  • located a clear spot to park
And.... right on time the AO-51 downlink signal started filling my car, even just above the horizon. It was audible for the whole pass, altough did not move the S-meter (on my non resonant antenna).

For another pass few days later I had assembled a Moxon directional antenna (two elements, folded), and tried again. While it did improve the strenght, sitting on a concrete floor created a lot of reflections and I could not follow AO-51 in its flight over my head. It was strongest when beaming to the ground! But the antenna works as expected, if pointing some ground-based signals.

Anyway, a short youtube video with audio should show you how easy AO-51 is.

On the second attempt I actually received another "bird" sending CW telemetry on the same frequency (435.3 MHz +/- doppler), but I was unable to discover who it was, yet.