On Sat, 22 Oct 2005 19:46:51 -0400, "E.F." wrote:

What are some of the interferences out there that mess up SW?? It seems
that everytime I have my laptop on it get a high pitch tone.

EF

The inverter that powers the backlight on the display is the likely
culprit. It is kind of like the Horizontal output on a TV, nice saw
tooth wave with harmonics that reach well into the HF spectrum.

Just about every other clock inside the computer runs at frequencies
well above HF.