"Jim Leder" wrote in
:

Most newer TVs use switching power supplies and some generate bad RFI
when just plugged in, they don't need to be switched on. Another
source is PC CRT monitors. Same kind of power supply and same kind of
RFI. I have a 17 inch Cybervision on PC #2 in the basement and it
generates enough RFI hash to render much of the AM broadcast band
useless when it's plugged in.

You sure that it is the switching power supply and not the high voltage
circuits? I have a Philips 107T5 (17") that gives interference around 1500
khz and not around 700 khz. I am running in 1024x768 at 85 hz, and if I
change to 75 hz, for example, the interference (a high pitched whine)
moves. The radio is about 4 feet from the monitor. Over 10 feet there is
no interference at all.