[Elecraft] K2/100 RS-232 Noise

[Jim Brown]

I suggest a different solution. Rebuild the serial cable using the 
techniques detailed in Chapter 8 of my RFI tutorial. 

http://audiosystemsgroup.com/RFI-Ham.pdf

Also, the coupling mechanism for the noise is very likely a "pin 1 
problem," also discussed in that tutorial. The ONLY good termination for 
a cable shield is the shielding enclosure (the chassis) of the equipment 
on each end. When you tie the shield to the "audio ground" or "control 
ground" or "signal ground," it allows the cable shield to radiate RF 
trash from the equipment, and it also allows the cable shield to RECEIVE 
RF from your transmitting antenna (also known as RF feedback, or "RF in 
the shack"). 

73,

Jim Brown K9YC