I don’t think I ever posted a video showing the built-in AFSK1200 demodulator and decoder in Gqrx, so here it is. The video show local APRS traffic in Copenhagen on a Sunday afternoon. I also tried to receive from the ISS but nothing heard this time.
Last week I started on a new experiment trying to integrate the AFSK1200 demodulator code from multimon into a simple Qt-based graphical application. This experiment had two objectives:
- Test the feasibility of integrating the AFSK1200 demodulator from multimon into other applications.
- Try using the QAudio framework from Qt for audio I/O that should work on both Linux, Windows and Mac OS X.
As promised yesterday, here is the video tutorial showing how to connect the demodulator output of a GNU Radio receiver to the input of the multimon software modem.
On July 10, 2010, I was listening to the linear transponder downlink of VO-52 when I suddenly noticed a very strong peak about 50 kHz below. I checked Gpredict and found out that it was the APRS downlink from the International Space Station RS0ISS on 145.825 MHz. Thanks to the flexible GNU Radio framework and the USRP, I could easily receive both satellites at the same time as shown on the video below.