[Elecraft] Good Low Cost Audio to USB Interfaces For Digital Modes

[Igor Sokolov]

Jim,
Thank you for the research.
Do you think these two cards will be good candidates for mating with KX3 and 
netbook to be used for panadapter and SDR?  Are they 96khz or only 48?

73, Igor UA9CDC


----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
To: "Reflector Elecraft" <elecraft at mailman.qth.net>
Sent: Friday, March 09, 2012 7:59 AM
Subject: [Elecraft] Good Low Cost Audio to USB Interfaces For Digital Modes


> in the last few days I've been evaluating a couple of low cost audio to
> USB interfaces for use primarily with digital modes -- RTTY, PSK, JT65,
> FSK441. My primary objective is to improve decode performance at low
> signal levels. I studied the catalogs and chose two low cost units that
> looked like they would do the job and would not have RF problems.
>
> Here's a link to a little Numark adapter that I bought for $33.  t's as
> cute and easy as it looks.  Power from the computer, a couple of RCA to
> 1/8-in cables for gozinata and gozouta.
>
> http://www.bhphotovideo.com/c/product/639303-REG/Numark_STEREO|IO_Stereo_iO_USB.html
>
>
> The other one I bought is this Tascam unit.  A bit larger, more
> mechanically robust, mostly metal enclosure, more flexible with respect
> to levels.  The 1/4-in jacks for guitar and mic have more gain, so will
> work with lower signal levels.  $70
>
> http://www.bhphotovideo.com/c/product/648495-REG/Tascam_US_100_US_100_USB_2_0_Computer.html
>
>
> To evaluate them I hooked them to different Thinkpads running JT65-HF
> and fed both of them from the line of a K3, then compared their decode
> performance, and also compared them with the Thinkpads' internal sound
> card.  The two new adapters performed equally well, and often produced
> almost twice as many decodes on a given pass as the the internal cards.
> Next I transmitted through them and looked at their spectrum on a P3
> hooked up to a second K3. Distortion products look minimal on both units.
>
> I also pulled them apart and studied their construction.  Both use
> proper construction that avoids the Pin One Problems that cause RFI
> issues. Now that I'm sure that they work well, I'm rewiring my station
> to use them in place of the sound cards built into my Thinkpads for SO2R
> contesting and everyday digital operation on both HF and VHF.
>
> Both of these units are a real bargain from well known audio vendors.
> Their interface to the K3 (and other rigs) is really simple. They don't
> do any control functions, so you still need a serial or USB to serial
> for that. I use VOX to key the K3.
>
> Both are available from other vendors, but B&H had the best prices I
> found, and shipping by UPS Ground was free.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html