I bought one of those a few months ago (it was sold under a different brand
name but it looks and cost the same.) I did detect noise on the waterfall at
some parts of the audio spectrum when receiving PSK through a narrow filter.
The noise was outside the filter passband and would probably not be noticeable
against the background of noise and signals but it could interfere with weak
signal decoding.
Because of that I started using the cheap USB adapter for computer sound and
the on board sound for digital modes. Subsequent to that I was listening to a
recording I had made on another computer of weak CW (actually it was EME
signals from Arecibo) and found that the CW signals had disappeared! All I
could hear was band noise. I switched to the on board sound card to play back
the recording and it was then played back as I originally heard it.
This leads me to suspect that these USB sound cards resample the audio to a low
bit depth and sample rate in the drivers, which results in the loss of weak
signal information. This could result in not copying weak digital signals that
a better sound card would allow you to hear. I suspect that the software
resampling could also put a load on the CPU that an internal sound card would
not, which might impact performance of the digimode software in other areas.
Julian, G4ILO
--- In digitalradio@yahoogroups.com, Rik van Riel r...@... wrote:
On 06/05/2010 03:24 PM, Jeremy Cowgar wrote:
Do you have any ideas? It's just $10, but I'd really like to have a
dedicated sound card for the ham stuff, and please do not suggest a
Signalink as I already have a nice setup,
I know your problem - the sound card's too expensive :)
I got a Cmedia Cm108 USB soundcard for $7 and it seems
to do the trick here. The sockets for the connectors
are not very good physically (I ended up soldering wires
directly to the circuit board) but the audio quality is
perfect for HF.
--
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