Saturday, November 8, 2014

Using GNURADIO-Companion and HackRF One as a CW beacon


One this video you are listening to the CW that was generated in a WAV file and is being sent to the HackRF One via GNURADIO using USB.  The result is a pretty clean CW tone being received by my FTDX-5000 on 50.075.2 Mhz.  

This is just some testing I'm doing to learn really.  I doubt this is the best way to do it, but it's ONE WAY that seems to be fairly simple.

In my next test for this I'll move to running this same flow-graph on the Beaglebone Black and see how well it performs.  I'll post an update for that test on this posting below...once I've done it.

NOTE: I have noticed some fairly minor carrier drift as the hackrf gets warmed up.  At these levels it doesn't get warm to the touch at all.   But I assume it's related to internal warming.  Regardless I think this can be overcome using a GPSDO and a 10Mhz clock signal into the HackRF.  It already has SMA connectors ready for that, and I intend to try to do that soon as well and retest this again to see if I see any drift.

I'm constantly learning stuff with this, and I'm sure I'm probably not going about this the best way, but it does seem to work just fine.  I'll post the GRC I'm using and details on how I got the WAV File Source setup in a while.  (hint that's SUPER EASY!)


  • THIS SITE  will generate a WAV file @ "128 kb/sec bitrate, 8 kHz sample rate, 16 bit sample size, single channel, pulse-code modulated audio."
  • Convert the sample rate down to 48kb/sec here
  • Now you have your WAV FILE SOURCE for GNURADIO.
  • Get this FILE. (grc file)
  • Start up GNURADIO and open the GRC file noted above.
  • Edit the WAV FILE SOURCE and change the path to that of the WAV FILE you created above.
  • Click to generate the flow-graph.
  • Click to run the flow-graph.
  • Done.