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--QMX+ has an I/Q mode, that uses the soundcard as interface, allowing for a panadapter.
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You need bandwidth in the data or baseband that is not there outside of the design bandwidth.
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>A perfect solution for CW operation: Everything you need. Not-so-perfect for digimodes or future SSB, though: Those modes do need the soundcard for the audio data, so the current implementation does not allow for the use of the I/Q mode in the same way you can do in CW (this sentence may contain wrong assumptions as I do not have QMX at hand, yet). Also, the manual states, that the I/Q data delivered over the soundcard is not suitable for decoding digimodes. I remember having read thoughts about a? possible future implementation of a different type, maybe QMX+ will have that feature out-of-the-box some day, but while Hans is busy on ticking the SSB-To-Do-List, maybe it's not the right time to propose even more features... <
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Also the sound card interfaces are audio band width for all digimodes typically 3-4khz wide.
ITs limited to that as most radios have IF filters that are of at most FM bandwidth (15khz)
and for SSB modes (including Digital) typically less than 3.2khz.? ?For most radios that's all
the bandwidth possible.? They all do SSB well.
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What you thinking of is typical of the later generation of SDR (hybrid or direct RF to digital)
that have wide bandwidth digital conversion for later processing.? Example is IC7300, IC7610 (dual RX).
The digital stream bandwidth is megahertz in band width width.
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Your understanding of the QMX and QDX receiver is not complete.? It does digimodes as is (same as QDX)
as well as SSB RX.? I find the RX well suited (QDX and QMX) for digi-modes (all for RX) and depending on
the specific modes many for TX but not all (PSK31 RX is fine but not TX).? The reason is the RX is a fully
developed SDR receiver but not transmitter SSB will be done using SDR techniques but in a different way.
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You ned to read the white papers for both QDX and QMX... maybe even QCX as the down converter to
baseband is similar in all of them and they differ from QCX to later QDX/QMX in the post processing
of that baseband.?
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For Digital modes you only need audio bandwidth I run FT8/FT4 with 3KHZ wide and WSJT-X
takes that and gives me a very fine grained RX waterfall on the computer.
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Older multiple conversion transceivers often have SDR (built in, often hidden) with 22 or
25khz IF and most can easily be tapped before the first filter (usually a VHF frequency 45
to 65mhz) before its converted to some lower IF (for electivity) and converted again for
the internal analog to digital conversion.? They are all fundamental Superhet technique
and differ only in the last stage (detector).? The techniques you write about are suitable
for them.
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Allison
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