"Jim" writes:
It's called "Olivia." It's a MFSK variant with multiple tones and bandwidth
settings which are currently user selectable The default setup is 32 tones
with a bandwidth of 1000Hz. The mode uses forward error correction allowing
weak signal reception. The made is being developed by Pawel Jalocha,
SP9VRC.

I wonder why anyone is messing with these modes instead of doing DSSS,
now that we can digitally-process the daylights out of the received
signal instead of messing with analog filter banks or whatever. I've
been hoping for something even slower than PSK31, spread over an
entire ham band or even multiple bands. I'd think something like that
would be ultra-reliable through just about any amount of interference.

DSSS is nowhere near the best modulation format in the presence of
narrowband
interference. OFDM is far better suited in this case as was shown in ADSL
trials (examing the effects of cable crosstalk). We found the same during
our
amateur spread specturm experiments in Dallas in the 902-928 MHZ band in
the late 1990s where DSSS was far inferior to frequency hopping with bad
channel notching.

-- Tom, N5EG




"Paul Rubin" wrote in message
...

SNIP


I wonder why anyone is messing with these modes instead of doing DSSS,
now that we can digitally-process the daylights out of the received
signal instead of messing with analog filter banks or whatever. I've
been hoping for something even slower than PSK31, spread over an
entire ham band or even multiple bands. I'd think something like that
would be ultra-reliable through just about any amount of interference.

On Fri, 7 Jan 2005 17:43:53 -0500, "Jim" wrote:

Thanks Jim, I ran it down and joined the digitalradio reflector yahoo
group which has some info there. Also worked a 3 way on 80 meter MFSK
tonight and both guys had Olivia capability and were most helpfull.
But 1khz BW? Jury is still out on that one. Cheers Nigel VE3ELQ

It's called "Olivia." It's a MFSK variant with multiple tones and bandwidth
settings which are currently user selectable The default setup is 32 tones
with a bandwidth of 1000Hz. The mode uses forward error correction allowing
weak signal reception. The made is being developed by Pawel Jalocha,
SP9VRC.