[Elecraft] Suggestions for good 192kHz external sound card for digital modes

[Wes (N7WS)]

Operationally, at least with a K3 and the modes I operate I've seen no 
difference between the built-in sound card on my Lenovo T400, a TASCAM US-100 or 
a SignaLink.

Admittedly, I haven't yet tried the digital modes that dig out imaginary signals 
from the noise, but on RTTY and PSK I simply can't see an advantage to a better 
sound card.  My T400 is what I use.  I sold the SignaLink, so I can no longer 
compare but I just did a quick test on the other two.

Using Spectrum Lab and listening to my Elecraft XG2 on 14 MHz with the K3 line 
out into the sound card, the SNR with either the T400 or the Tascam is about 50 
dB.  This is with the XG2 set to low power (~S3), AGC off, 400 Hz crystal 
filter.  The filter shape is easily seen and disconnecting either card drops the 
baseline noise about 30 dB.  I say "about" because about is good enough.  The 
T400 is slightly microphonic but this is only seen with no audio input.

IMHO, the SNR is set by the receiver and the defects in any practical sound card 
are, excuse the pun, in the noise.  I'm looking at a couple of KHz of audio, why 
would I need a 192KHz, 24 bit card?  (Actually, the T400 card is such)

All of the other hand wringing about PTT, Windows sounds, etc, are just that, 
hand wringing.  Turn off Windows sounds, turn on VOX and enjoy.

Wes  N7WS



From: "David Orman" <ormandj at corenode.com>
To: "elecraft" <elecraft at mailman.qth.net>
Sent: Tuesday, November 11, 2014 7:08:12 PM
Subject: [Elecraft] Suggestions for good 192kHz external sound card for digital modes

Hi,

Splitting off from the Signalink thread, since it's actually a different
question, what are the current external sound cards that people suggest
(that are supported in Linux if known - if not - that's ok)?

I see the Tascam mentioned in the PDF in the other thread, so I'm looking
into those (the ones that support 192kHz now, that is) - are there any
other suggestions to look into? I operate on a lot of digital modes, but my
Lenovo Thinkpad T400's built in sound card adds a lot of noise to the
signal I'm receiving. I have a Native Instruments Audio Kontrol 1 which
works much better, but it is USB powered (it seemed to be indicated this
was a no-no for best decoding in digital modes in the other thread).

There are a lot of options out there now, so it's hard to sift through them
all, and make a guess as to which are best for HF radio digital
communication, so I thought a thread would be helpful in getting some ideas
on what is tested/true. If Linux support is unknown, that's ok - I can do
that research - but it would be great to have a list to start looking at
that are known good performers with low noise.

Thanks!
David/K5DJO