I tested the cheapest USB sound card I could find. It had high levels of
aliasing distortion that created false RTTY signals off set from the real
one at about -30 to -40dB down. At some tone frequencies this would coincide
with the wanted signal.
I also tested a very expensive one that I use for SDR and I concluded that
while excellent for SDR use for normal RTTY use it would be a a waste of
money - spend the money on another part of the station.
My suggestion is that internal sound cards are good for RTTY and external
ones about $25 should be OK. But avoid the $5 "bargain".
73 David G3YYD
-----Original Message-----
From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Ed Muns
Sent: 24 March 2016 21:22
To: 'Michael Haack'
Cc: 'RTTY Reflector'
Subject: Re: [RTTY] A Question for Chen... Soundcards?
Over the years, I've found all internal soundcards to be more than adequate
for RTTY with respect to SNR, dynamic range, etc. (That may not be true for
other digital modes, however.)
The limitation is the absence of a stereo Mic or Line In input for SO2V or
SO2R. So, I use a $20 external USB soundcard dongle that has stereo Line
In. Some new radios, e.g., the Elecraft K3S have a built-in USB soundcard
with stereo Line In which simplifies station wiring.
Ed W0YK
______________________________________________________________________
Mike WB9B wrote:
I had a brief question the other day that I had bounced off Don, AA5AU.
We both figured you were the guy for this.
I can't recall if you've ever addressed the issue but here it is.
Is there a decided advantage to using a high powered external sound card vs
the internal card for RTTY/MMTTY/2tone use?
Or is it just a waste of horsepower (so to speak)
I would tend the think the more important number would be the S/N floor and
Dynamic Range of the respective cards, as opposed to their DSP capabilities.
Thoughts?
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