Scrolling waterfall and audio

  • 4
  • Idea
  • Updated 5 years ago
I would like to suggest a feature with the upcoming Ver. 1.2's panafall scroll back feature. Please include the ability to play back audio anywhere in the spectrum displayed while scrolling back. This would not be a quick record function. Just put the active slice anywhere desired during a waterfall scroll back and listen to what you missed. Could be a correction to the DX call, signal report...anything. This would be awesome for both dxing and contesting.

73
Greg
AB7R
Photo of Greg

Greg

  • 656 Posts
  • 63 Reply Likes

Posted 5 years ago

  • 4
Photo of Ken - NM9P

Ken - NM9P, Elmer

  • 4025 Posts
  • 1248 Reply Likes
That is an interesting concept.  Like a "blackbox recorder" for the panafall.  It automatically records the last 10 (or 30) minutes in something like a FIFO buffer that can be scrolled back and played again.... That would make BCB or SWL DXing interesting, too... record 5 minutes each side of the top of the hour and then go back and play back every signal you see to get the station ID.....

I don't know how much CPU & HD real estate this would consume, but it is an interesting concept.

BTW, I can already do this apart from real time by recording DAX IQ on Audacity from my 6500 for a time and playing it back on my FLEX 1500.  But I only get to use 48 Khz of the band.  3000 & 5000 owners could use a much larger slice....
Photo of Greg

Greg

  • 656 Posts
  • 63 Reply Likes
Yes but that is more of a kludge than a feature. When you do that does it record the entire displayed panadapter and let you go back to any signal in the display and listen to it? If so, how many steps does it take? I imagine quite a few. I am thinking just one button to turn the feature on or off. If on, it would continue to capture the last x minutes so the file does not get out of hand. Then when you use the scroll back function you only have to put the slice on whatever signal you want to listen to from the past x minutes.
Photo of Ken - NM9P

Ken - NM9P, Elmer

  • 4025 Posts
  • 1248 Reply Likes
Yes, my way is more of a process, and only records whatever bandwidth I have DAX IQ set to pass, but it is fun to play with.  

Steps:
set up DAX,
start and configure Audacity, set levels, hit RECORD,
hit STOP,
export & save recording to a file
switch to 1500 and open wave menu
find DAX IQ recording
hit play & loop buttons
tune in stations

Yep... a bit of a kludge.... Of course, I could just record the IQ straight from my 1500, but how would THAT be any FUN?  <grin>
Photo of Peter Driessen

Peter Driessen

  • 17 Posts
  • 1 Reply Like
Depending on how the internal software is configured, it may be possible to record a IQ stream at a higher sample rate say 1.536 MHz, as is done by the QS1R receiver with SDR Max V.  You can then play back the recording and tune to any signal within the recorded bandwidth.
Photo of Greg

Greg

  • 656 Posts
  • 63 Reply Likes
Yes but what I am suggesting is more simple than that. No record buttons or play back buttons. Just using the waterfall scroll back, tune the slice to the signal you want to hear...thats it.
Photo of Robert -- N5IKD

Robert -- N5IKD, Elmer

  • 488 Posts
  • 152 Reply Likes
Like a DVR, always recording a buffer.
Photo of Michael - N5TGL

Michael - N5TGL

  • 307 Posts
  • 101 Reply Likes
Yep, that's exactly it.  Seems that the IQ data is being buffered for the waterfall already, so this might not be too tough to implement?  Heck, I'd be tickled pink to even just have a 30 second audio buffer.  In fact, that'd probably be all we'd ever need.  I think a 10 minute buffer would be overkill.

This truly would be a game changer!
Photo of Rick Hadley - W0FG

Rick Hadley - W0FG

  • 579 Posts
  • 121 Reply Likes
Long ago, and far away, an agency that Never Says Anything used to do something like that with a tape-based system.

Photo of Steve - N5AC

Steve - N5AC, VP Engineering / CTO

  • 1031 Posts
  • 1002 Reply Likes
Each SCU produces 29.5GB of data per minute ... currently we do not have a good place to store that.  Even if we only did it for a 14MHz panadapter, after IQ mixing we still would have to store 11.8GB per minute of data.  It would be easier to do it on a more zoomed-in panadapter, though.  192ksps data is a mere 92MB/minute.
Photo of Michael - N5TGL

Michael - N5TGL

  • 307 Posts
  • 101 Reply Likes
I'd be pretty happy with getting the last 30 seconds of audio in the visible panadapter.  Maybe limit it to 20 mhz either side of the tune frequency?