[Elecraft] K3 and data modes

[Jim Brown]

On Mon, 28 Dec 2009 16:20:44 +0000, Ken Chandler wrote:

>Working. PSK es AFSK data modes I have always used isolation  
>transformers between the radio es computer to prevent ground loops 
etc.
>If I direct wire line in, line out to the K3 &  computer what is there  
>to prevent RFI ground loops etc.

TOTALLY UN-NECESSARY!  As others have noted, the K3 works VERY WELL in 
data modes with nothing more than properly wired 1/8-inch cables 
between LIN OUT and a computer sound card, and between LIN IN and the 
sound card, PLUS simple (and quite proper) BONDING between the chassis 
of the computer and the chassis of the K3. See 

http://audiosystemsgroup.com/HamInterfacing.pdf  (Power Point slides)

and the Appendix on audio in 

http://audiosystemsgroup.com/RFI-Ham.pdf   (a tutorial that goes with 
it)

I do LOTS of RTTY contesting, as well as some PSK31. For RTTY, I use 
MMTTY, along with N1MM Logger if it's a contest. For PSK31, I use DM780 
and HRD. I use VOX rather than PTT. 

Note also that RTTY and PSK31 decoding software will refuse to decode 
the combined output of the two receivers in Diversity mode, thanks to 
small time offsets between signals from the two RXs. These offsets are 
both within the K3 DSP system and the RF path to different RX antennas. 

73,

Jim Brown K9YC