[WriteLog] Computer hash in the audio

[K5RC at aol.com]

I've loaded WL 10.50 on my laptop for the second station. Everything  works 
great, except using the internal sound board for a voice keyer. Regardless  of 
where I set the level controls, there is an objectionable amount of computer  
"hash" embedded in the audio. The hash is definitely from the computer  
because its modulation changes when I open and close programs. I can get  rid of it 
by muting the mic input or unplugging the mic cable from the computer,  which, 
of course, kills the audio.
 
I've tried several microphones, additional cable shielding, etc., with  
absolutely no difference. The audio input and output are run through  isolation 
transformers, although it behaves the same with or without them.
 
 
Another curiosity is that the noise drops significantly when I unplug the  
power cord. I have added torroids to the power cable and used several  power 
supplies, but none of that helps. I can't swap batteries every two hours,  so it 
has to be plugged in.

 
Any ideas?
 
Tom  Taormina, K5RC
Virginia City, Nevada
Contesting from the Comstock
W7RN  - K7RC
_www.ConsultPR.com_ (http://www.consultpr.com/)