OSCAR-100 amateur narrowband testing

The QO-100 narrow band transponder was opened for experiments this afternoon, prior to the official inauguration on Thursday. I simply had to have a look!

Amateur signals on the narrowband transponder 10GHz output

There we are! Not strong, but clearly visible.

The signals are strong on the online WebSDR, but of course that has a decent size antenna. My system has a 60cm dish, a cheap unmodified LNB (though modern with a PLL local oscillator), a cheap DVB-T dongle for the IF, and a Rapberry Pi running gqrx as the receiver.

I decided I should peak up the system on the engineering beacon:

The 10706MHz engineering beacon

Having done this, the amateur signals on the narrowband transponder were a bit stronger too. And I still haven’t tweaked the LNB polarization angle which might give me a few more dB!

In the narrowband section with stronger signals

After a while there were quite a few people on, and I managed to hear some calls quite clearly, despite my minimal system. The gqrx sound is a bit crackly if FFT processing is heavy, but with sample rate turned down a bit it’s fine. Here’s a recording of part of one QSO:

The sector was nowhere near overwhelmed, but there were a few people on – some with signals too strong suggesting that their receive capability at 10GHz was not up to much!

The narrowband sector getting busier

So, fun fun! Maybe I should try setting up on Thursday to see if I can see what signal I can squirt up there. I have only low power and a Yagi but who knows?