On Nov 28, 9:39 am, David wrote:

My Dad had an aquarium heater with a neon lamp that destroyed my MW
listening when I was a kid.

Also, the neon lamp in a lighted doorbell button can become a random HF
static generator audible for a hundred feet or more.

Solid state motion detector lamp controllers are also very odious. The
ones from Grainger with a relay are OK.

I failed to include the latest wrinkle in heat pumps.

The single phase 60Hz is converted to variable frequency

3 phase to drive both the compressor and the blower.

The better units use 2 converters, each optimized for
the motor it is driving.

These are very efficient, but the 11 I have seen have
all had intense RFI that will be very difficult to reduce.

I also neglected to mention exterior "security" lights.
Both Mercury and "low pressure Sodium" lights can be
major RFI offenders. In my experience the photo eclectic
controllers can be nasty RFI sources even when the light
is off.

Terry