Monday, February 04, 2013

My second DV QSO

Elie, OD5KU
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.

7 comments:

sv3auw said...

Well... No!
I'd rather stay analog!
It is the same disagreement I have with my friends, SDR "fanatics".
The less equipment you use home or /p, the less prone to failures and disappointment you are.
One rig, one battery, a key and/or a mike, a roll of wire.
King of the airwaves!

Nice hear your voice Julian!
73
Panos

Paul PC4T said...

Hi Julian, the quality is outstanding. I think there is still a future for phone. 73 Paul

Julian Moss said...

Perhaps I'll hear you on DV mode soon, Paul.

Julian, G4ILO

Anonymous said...

Hi Julian, I've tried in vain to install FreeDV on my Linux PC, which is a shame because I quite fance trying this mode out.

Anonymous said...
This comment has been removed by a blog administrator.
Julian Moss said...

Have you tried running the Windows version under wine?

If I were you I would plead with the developers to make a Ubuntu .deb binary package available. The trouble with .rpms is they really only work on Red Hat which is not a popular distro among the ham fraternity.

Julian, G4ILO

Fenris said...

There are lots of rpm-based distros, RH, Fedora, SuSE and Scientific Linux among others.

Fedora has a good range of amateur radio software and FreeDV is available in rpm form.