Thoughts on a Wideband SDR Recording Tool

As part of the HamSci Solar Eclipse experiment, I recorded wideband data from my SDRs on the theory that capturing the data for later study might be more productive (and less stressful) than trying to do measurements in real time. I think that theory played out very well.

I used a simple Gnu Radio flowgraph to do the recording from an HPSDR Hermes receiver. When I say simple, I mean simple. Here’s the whole thing, which records four 384 kHz wide band segments simultaneously:

While the Gnu Radio Companion WYSIWIG program is nifty, there’s quite a learning curve. It would be nice to have a recording program that’s not quite so intimidating. This post is a wish-list of what I’d like to see that program do. Almost all of the functionality exists within Gnu Radio; what we need is a GUI front-end to make it accessible. Unfortunately, GUI coding is not my strong suit, so I’m looking for a volunteer to take this on.

Here are the basics:

• Cross-platform Windows/LinuxMac
• Built on Gnu Radio framework, using QT graphics
• Supports any source block available in Gnu Radio (in particular, HermesNB, PitayaWB, RTL-SDR), and as many receiver slices as are available from the source
• Outputs HDF5 or standard Gnu Radio complex float (maybe also .WAV?)
• Display includes:
  

  • FFT for each receiver slice (FFTs can be turned off to save CPU)
  • Master sample rate setting (same for all slices)
  • Center Frequency setting for each slice
  • Setting output file directory and name (and hide HDF5 complexity)
  • Record Start/Stop button (also include “start over” capability?)

• Wish List: Start recording at specified future time
• Wish List: Automatic naming scheme that includes center freq, sample rate, and start time
• Wish List: Auto-delete function to delete old data as needed to make room for new
• To Research: Since all receivers currently are 16 bit or less ADC, can we store complex16 rather than complex32 to save storage space?