- Published on Tuesday, 05 February 2013 06:10
- Written by Rizkallah Azrak - OD5RI
Article written by Julian Moss, G4ILO, as published on AmateurRadio.com on February 4, 2013
"Just as I was finishing writing my previous post I heard someone else calling on the 20m DV frequency. It was Elie, OD5KU. Yesterday I had heard him working a French and then a Dutch station but signals were weak and not good copy at all.
I replied to Elie but he couldn't make out my call. I tried several times and was about to give up when he called again with solid copy. Perhaps he had turned his beam my way. I tried calling one more time. This time he heard my reply and we had a good QSO with several periods of solid copy punctuated by occasional break-ups. These occurred when QSB took the digital signal down to near-invisibility in the FreeDV waterfall. I doubt that good SSB copy would have been possible at those times either. I managed to make a recording of the end of this QSO so you can get an idea of the audio quality. It was recorded off-air using my Olympus digital voice recorder, then played back using the mic input of the USB sound dongle to make an MP3 file.
Given the way it was created I think the clip is quite a good example of the FreeDV audio quality. As you'd expect from a digital signal either it's all there or you just get gobbledygook. It doesn't degrade gracefully. Is this the future of ham radio? Have a listen and let me know what you think."