Plug-in surge protectors don't even claim to protect from
the destructive type of surge. Why will it stop a transmitter
inside the computer from transmitting noise? Protector does
not claim to do that either.

You don't yet know what the noise source is. For example,
computer power supplies priced for less than $80 retail are
missing essential functions include EMI/RFI filters. The
solution to noise on power supply cord is a power supply that
meets Intel ATX specifications (which $40 power supplies do
not). That printer cable could simply be an antenna to
transmit motherboard or power supply generated noise.

Better motherboards include filters on that printer port
cable. Just another function often missing on some clone
motherboards.

Your solution is found inside the equipment - and not in
some plug-in component.

tommyknocker wrote:
When the SW interference got worse today, I walked around the room
(to start out) with my 396 and noted that the hum was so loud next
to my computer that the signal light lit up. I turned off the power
supply and the noise went away. I'm thinking "great, I need to buy
ANOTHER surge protector". But then I played a hunch and started
unplugging stuff one by one to see if it's really the surge strip
and when I unplugged my computer's printer the noise went away.
Plug it back in, and the noise returns. So instead of spending $20
on a surge protector, I'm looking at $120+ for a new printer. But
that's ok since it was acting up in other ways, for example the
paper feed quit working so it wouldn't automatically feed paper
through, I had to feed it each sheet by hand. It's not always a
power line problem, guys. I think the other guy who was having a
hum on the tropical bands should try what I did.