[Elecraft] Making a Signalink cable for the K3's 8-pin micconnector

[Jim Brown]

On 5/9/2014 1:26 PM, Wes (N7WS) wrote:
> Likewise, after your glowing recommendation of the US100, I bought one. 

Hi Wes,

I did my testing with JT65HF on he HF bands, with the K3 output feeding 
both one Thinkpad internal sound card and the Tascam feeding a second 
Thinkpad. I did the same comparison between the Numark and internal, 
then between the Tascam and the Numark. My criteria was the number of 
good decodes for each 1 minute pass. The Tascam and Numark boxes 
consistently decoded twice as many signals per 1 minute pass. The 
internal sound card rarely decoded a signal weaker than an indicated 
-12, whereas the Tascam and Numark regularly decoded additional signals 
down to -20, with occasional -22 decodes. I attribute that to better 
performance near the bottom  of the A/D. When comparing the two USB 
boxes to each other, roughly once in ten passes, one would decode a 
signal that the other would not, but neither was better than the other 
-- on one pass the Tascam would miss a station that the Numark copied, 
then 5-10 minutes later the Numark would miss a station that the Tascam 
copied. This was quite extensive -- in addition to watching the nigher 
bands, I even let them run overnight on 160, then compare decodes the 
next morning.

I found performance "a bit better" with RTTY, but did no equivalent 
testing to substantiate that, because I found the JT65 results far more 
quantifiable and repeatable. So for RTTY contesting, the Tascam is on 
one rig feeding one laptop, and the Numark is on the other rig, feeding 
the other laptop. Now that we have 2Tone as an alternative to MMTTY, 
I've been running three decode windows per radio, and the most I can say 
to describe the result is that they are about equally good, but on 
almost every pass, one of the windows will copy something that one of 
both of the others missed, not no consistent advantage I've been able to 
discern to one over the other. The real advantage is that you have three 
looks at the same signal, so you tend to ask for far fewer repeats, AND 
I have changed to not repeating the exchange. I notice W0YK doing the same.

73, Jim K9YC