Spectrum Recording

Bay Area Flight

John Malsbury and I taking SDR to the skies

Equipment/Software

• USRP N210 + GNU Radio used to recording spectrum at different frequencies and bandwidths based upon pre-determined schedule
• HDSDR used to review recordings

Documentation

• Gallery of photos from the air (aerial photos of the Bay Area)
• Video of equipment and takeoff

Code

Scheduled Recording

WARNING: This was hacked up just before the flight. There are many things to be fixed/added (e.g. ability to set receive port when using multiple antennas).

The code to perform the following can be found in ScheduledSpectrumRecording.zip.

• Create a simple flowgraph in GNU Radio Companion with Parameter blocks to set properties of your capture device
  • Destination should be a File Sink with the destination path set using a Parameter
• Write the schedule in a text file where each line consists of:

 <Frequency (MHz)> <Name> <Bandwidth (Msps, default: 1)

• A file of '-' implies a delay.

• Run timed_rx.py passing in your schedule, which has various command-line options:

("-g", "--gain", dest="gain", type="eng_float", default=eng_notation.num_to_str(25), help="Set Gain [default=%default]")
("-a", "--ant", dest="ant", type="string", default="TX/RX", help="Set Ant [default=%default]")
("-s", "--samp-rate", dest="samp_rate", type="eng_float", default=eng_notation.num_to_str(1000000), help="Set Samp Rate [default=%default]")
("-x", "--time-multiplier", type="float", default="1.0", help="Time Multiplier [default=%default]")
("-p", "--progress-step", type="int", default="1", help="Progress Step [default=%default]")
("-b", "--base-path", type="string", default="", help="Base Path [default=%default]")
("-c", "--run-count", type="int", default="1", help="Run Count [default=%default]")

After returning:

• Run raw capture files through CFileToWAV (with schedule.txt in same directory) to generate Winrad/HDSDR-compatible WAVs