On a sunny day (Tue, 29 Apr 2008 16:55:12 -0500) it happened "amdx"
wrote in :

I have an undercounter AM, FM radio. When I plug the power supply to my
laptop
into an outlet in the same room, the FM signal gets very noisy. Upon further
investigation, I found that just plugging the ac cord into an outlet and
holding it near the laptop causes the noise.

Looks like that radio is using the main lead [power cord] as FM antenna.

So if you decouple that mains lead noise will _not_ get better.

Just keep the 2 separate.
Or, if the radio has an external antenna connector, use that.