re: "
Though he used what is called a "Pin-Diode" The fact is LED's do much the same thing."
yeah, a diode can make a great rectifier for your own 'crystal' type AM radio.
A PIN diode [
wikipedia] is rather common when speed is needed (e.g. microwave frequencies).
but the example is related to what Jeff described. The diode is a non linear device in an RF field that produces interesting waveforms with components at many frequencies - i.e. an excellent noise generator. It doesn't take much lead length to serve as an antenna.
The key here, though, is that some RF signal is needed as a source for the interference. You can get intermod and noise via an LED (or even a loose connection anywhere in an electrical system) if you are parked close enough to a radio station or have some other rather strong RF signal in the rig but that isn't likely. What is more probable is a PWM device operating at a few kHz with a lack of attention to inhibiting its radiating a signal.
Note also that appliances like TV's are supposed to be able to handle reasonable levels of RFI. (they shouldn't freeze, for example). Solving the problem may well be in adding some filtering to what is being bothered as well as to what is doing the bothering.
note: some diodes are used as noise sources but in that capacity they always need an amplification of the noise in order to be useful in receiver testing and whatnot. Otherwise, the noise amplitude is too small to do much. It might be possible to get some sort of resonance effect or something, I suppose, but the energy involved is so small I am having trouble seeing a diode in a DC circuit as being a significant source of RFI problems by itself.
Linear Mode
