FDMDV uses a 1400 bps codec, occupies only 1100 Hz and operates with any SSB transceiver. Comunications doesn't have to be full duplex. At 12-16 kbps the satellite and ground stations could alternate with short bursts of voice or text. This wouldn't fit in a 2.4 kHz SSB bandwidth but would require a 16-20 kHz wide filter or use of a transverter and a simple SDR radio like the SoftRock.
73, John KD6OZH ----- Original Message ----- From: "Gordon JC Pearce" <[email protected]> > >> KD6OZH's mentioning of a 1200 bps voice codec is very interesting, >> too. I see that DSTAR's AMBE is down to 2000 with error correction, >> and Speex operates down to 2000, too, though I think without error >> correction. (I find the latter much more engaging as a ham, since it >> is open source.) It would be a hoot to do a voice conference over the >> Internet using a sample of low bitrate codecs and just get a sense of >> what might be possible. One downside of voice is that it would occupy >> the transponder far more than messaging, and Bob's favorable power >> calculations would need to be estimated downwards. > > Would the packet satellite be capable of bent-pipe operation though? > You'd need to transmit and receive simultaneously to get that working. > I'd far prefer to use Speex rather than the locked-down proprietary AMBE > codecs. _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
