[Elecraft] 2 dB better reception in JT65 mode

[Jim Brown]

On 1/25/2014 9:50 AM, Edward R Cole wrote:
> The K3 is connected via the line-out to a Delta44 soundcard at the PC.

I don't know anything about this sound card, but I've worked a lot of 
JT65 and RTTY, and I found that a good semi-pro audio USB interface 
improved JT65 decoding a LOT as compared to the sound card built into my 
Thinkpad. With extensive testing of two computers next to each other 
connected to the same audio, the USB interface gave me twice as many 
decodes in a pass using JT65-HF, and gave me decodes about 10dB lower 
into the noise (fairly often in the range of -20 to -22).

I bought and tested three USB interfaces -- a Numark (about $35) a 
Tascam (about $75), and a little mickey-mouse sort of thing. The Numark 
and Tascam were equally good at decoding both JT65 and RTTY. The little 
thingy worked, but was so poorly built I wouldn't recommend it. The 
Numark has no model number, the Tascam has been discontinued and 
replaced by one with more inputs and a higher price. I'm confident that 
it works as well. Both the Numark and the Tascam units have line inputs 
and outputs, and RIAA inputs. The Tascam has inputs for guitar and pro 
mics, so it's a bit more versatile in accepting different input levels.

The Tascam is hooked up to my "main" K3, the Numark gets used with the 
other radio when I do SO2R RTTY contesting.

73, Jim K9YC