[Elecraft] Computer RFI in K2 -- Follow-Up

[Jim Brown]

On Tue, 6 Jul 2010 19:43:21 -0700, J. Wolf wrote:

>I'm still open to any advice from anyone who's dealt with this in the past.

There are several possible mechanisms for coupling the RFI you're hearing. 

1) Direct radiation from the wiring inside the computer because it is either 
poorly shielded or has poor circuit board layout. 

2) Common mode radiation from one or more of the cables connected to the 
computer. This is made worse by serial ports with pin 1 problems, and by 
serial cables that are not twisted pairs. 

A big dent can be made in #2 with suitable common mode chokes on that wiring, 
and by building a serial cable according to the instructions in my RFI 
tutorial. http://audiosystemsgroup.com/RFI-Ham.pdf  For the serial cable, see 
the Chapter on Solving Problems in the Shack. 

The only solutions for #1 are replacing the computer or the bucket treatment. 

73, Jim Brown K9YC