[Ham-Mac] Controlling computer-related line noise

[Philip]

At some time fairly close to Tue, 1 Mar 2005 14:34:06 -0800,
rumor has it that Michael wrote:

> Hey all..
> 
> I've had quite a bit of noise from my laptop when it's connected to my
> 
> radio via AFSK and audio out jacks. The problem presents itself when I
> 
> plug the power adapter into the laptop. At least an additional 20db of
> 
> noise! Otherwise it seems okay.
> 
> Any ideas where I would start as far as limiting this QRM?

It could be ground troubles. I quite often have trouble with the
computer audio ground being quite it's own thing. A transformer is the
easiest way to solve that problem. Mouser Electronics #421-ATS001 is
actually a telephone transformer but it does quite well with full range
audio, so for the audio bandwith of radio it is plenty.

http://www.mouser.com

Or it could be noise from the switching mode power supply. That will be
much harder to solve - unless you just run off battery!



--
        Philip          73, de
                        KB0SWA