My ham radio 110-13.8 V power supply interacts with my electric
frying pan. No matter how far away in the house I plug them in, there
is a harmonic that causes the power supply to make a loud hum.

I must choose between rag chewing and food chewing. Help. What gizmo
can I purchase to filter out the resonance between them? Actually, it
only happens when the pan is switched to "low", not on "high".