[Elecraft] Best Audio Interfaces 2020?

[Jim Brown]

On 6/15/2020 4:55 PM, Wes wrote:
> OK  QSL.
> 
> All of my computers have soundcards including the, soon to be replaced, 
> shack Lenovo laptop. I tried a TASCAM US-100, highly recommended by 
> K9YC, without seeing any improvement over the Lenovo on digital modes.

Hi Wes,

You might want to look at the piece I wrote on the topic, which details 
my testing. It was pretty rigorous. The USB interfaces I recommended 
were equally good, decoded to much greater signal to noise levels, and 
produced almost twice as many decodes as the sound system built into the 
two T43 Thinkpads used for the tests.

Pulling out the weakest signals requires a lot of dynamic range if very 
strong signals are present, and cheap A/D converters can have poor 
linearity close to the low end of the dynamic range. WSJT-X uses 48 kHz 
16-bit, theoretical 96 dB, real life more like 90. It's not unusual for 
there to be locals 30-50 dB over S9 when the band is open, so every 
little bit of dynamic range can matter when you're trying to work the 
weak ones. All of this is why I started my search in the semi-pro audio 
world.

One thing I differ with in the WSJT-X instructions is to set band noise 
to 30 dB on the green voltmeter bar. That's fine for modes like MSK144 
and ISCAT B, but gives up FAR too much dynamic range for modes like FT8, 
FT4, JT65, and JT9.

73, Jim K9YC