I was surprised to find so many videos on Youtube regarding Plasma TV
RFI (see below). Although the noise is not nearly as loud at my QTH as
it is in these videos, it is identical to what I hear right down to the
frequency shifts in the "buzz" that take place when the channel is changed.
It would appear that Plasma TV's have unique RFI signature that doesn't
seem to change much from one brand to the next. If that's the case, it
would certainly help to know this when trying to track down the source
RFI mailing list