Custom dual input for one LimeSDR on GQRX

System Development
1

Greetings,

For a student capstone project we are trying to complete a project on an VHF/UHF and S-BAND reception using two antennas, for the S-BAND part we acquird a dish antenna but our goal was to receive data from dual polarization cubesats. Oddly enough we acquired a dish antenna that is linear but gives us two lines, one vertical and one horizontal. We thought about feeding the output through gnuradio for processing in order to combine the two linear (V and H) and decode the received images.

Our question is about the software part, we learned how to use gpredict with gqrx on our limesdr for the VHF/UHF part. Now that we are working on the S-band part, we were wondering how to mimic the same process but by specifying as inputs the two lines we receive from the dish (Vertical (V) and Horizontal (H)). We thought about controlling our motor with gpredict, gqrx for the frequency and then connecting gqrx with gnuradio via UDP for post processing. But the problem is how should we connect these two input lines at the same time on gqrx…

If this is a bad idea and we should try another approach (while keeping the dish antenna because we can’t afford another one) please feel free to propose another method.

Thanks for the help!

2

If you have a limeSDR with two antenna inputs, you could open the antennas with channel 0 and channel 1 with gnuradio and do whatever what with the output from the two antennas.

4

What about the gpredict/gqrx integration ? Do you mean that we could just launch gpredict and gqrx to track the satellite and at the same time use gnuradio to post-process and we will still get the right reception without gnu being linked to gpredict/gqrx?

5

The limeSDR and gnuradio can handle two channeIs , but you would need to write another program to send the Doppler information to gnuradio.