On Sat,4/11/2015 7:10 AM, Randy Thompson K5ZD wrote:
I decided to try an external USB sound card for the mic input. I purchase a
SYBA SD-DAC63094 for $30 from NewEgg.
For several years, I've been recommending Tascam and Numark USB sound
cards designed for musicians and DJs for digital modes. Both are now
discontinued, replaced by newer models, but the newer Tascams are fine.
Both old and new are widely available on EBay at greatly reduced prices.
Poking around N8LP's website a few weeks ago, I saw that he is now
recommending an ASUS sound card for bringing quadrature IF outputs into
a computer for his NaP3 software. B&H in NYC is currently selling them
for $70. 192 kHz, all the ins and outs we need for both SSB and digital
modes.
There is GREAT virtue in using a sound card of this quality for digital
modes. I experienced modest, but noticeable improvement in weak signal
decoding RTTY when I switched from the sound card internal to my
Thinkpads, but the improvements with K1JT's WSJT family of modes is
dramatic -- the USB units decode twice as many signals per pass and
regularly 10-12 dB deeper into the noise.
I wrote up my test methods in a report that also includes a tutorial on
setting levels. http://k9yc.com/USB_Interfaces.pdf
Here's the Asus unit Larry recommends. My neighbor, N6NUL, bought one
and loaned it to me the check out. So far I've only looked at WSJT
decoding, which is quite good.
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=1086995&gclid=CKTt-q6u8sQCFRSIfgod3LQAVg&Q=&is=REG&A=details
73, Jim K9YC
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