As a follow up question, what types of digital communication protocols
can a sound card NOT accomodate? I know if can do RTTY, PSK31, etc...
what about PACTOR? MFSK? G-TOR? etc?
Also, is any soundblaster sound card adequate?

Thanks!
Dave

In article .com,
wrote:

As a follow up question, what types of digital communication protocols
can a sound card NOT accomodate? I know if can do RTTY, PSK31, etc...
what about PACTOR? MFSK? G-TOR? etc?

MFSK is no problem (gMFSK software for Linux, and I'm sure there's
plenty of Windows software available). I believe that PACTOR is also
possible. The newer PACTOR modes are proprietary (or so I understand)
and I don't think there's a freely-available software implementation
yet. I believe that one of the goals behind the SCAMP project is to
create an open-standards (and eventually open-source) protocol with
bandwidth and robustness similar to those of the newer PACTOR variants.

You would not be able to use a soundmodem setup (or a TNC) plugged
into standard radio's audio output port and mic jack, for any digital
mode whose bandwidth exceeds about 2.5 kHz. Some of the newer modes
(e.g. the OFDM multi-carrier system used by Radio Mondial) exceed this
range, and require a different sort of feed arrangement from the radio
(e.g. tapping into or downmixing the final IF to a center frequency of
around 12 kHz).

Also, is any soundblaster sound card adequate?

For many of the simpler modes, I believe that any decent card with
16-bit sample I/O capability will probably suffice.

Some PCs (especially laptops) have only MIC inputs, not LINE inputs -
these would probably require a resistive padder to reduce the radio's
signal levels to those acceptable to a MIC input. Similarly, these
built-in sound interfaces may be "convenience grade" - acceptable for
teleconferencing, but with distortion or noise levels or frequency/phase
response variations too high for certain digital modes.

--
Dave Platt AE6EO
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