Second build has shipped. Message will appear here when store is ready for third build ordering.

Measuring oblique ionograms using KiwiSDRs

After @WA2ZKD asked me multiple times about it, I finally figured out how to use KiwiSDRs (with GNSS enabled) to record oblique ionograms, i.e., how to synchronously tune to HF chirp sounders. Because the RX is not co-located with the TX they are called _oblique_ ionograms.

Thanks to @G8JNJ's wessex.* KiwiSDRs.

Each column consists of 10240 IQ samples intercepting the chirp which is 1440 samples long at `BW = 12 kHz`.

See also, (documentation is work in progress).


  • Impressive, that works surprisingly well. I'm curious how you did that.

  • Hi Christoph,

    That is a brilliant bit of work, and I think Peter, G3PLX, would be interested too.

    Now to how to combine that with the TDoA function :-)

    I'm located about 15km away from the Wessex site, and I could maybe generate some low power sweeps, if that would assist with any tests or further development work.



  • Hi Christoph,

    Also much impressed with these results so far and it will be interesting to see how you achieved this. I assume you used a form of matched filter for processing the wav file of the audio from the synchronized sweep.

  • Thank You!

Sign In or Register to comment.