[Sir Kenyth]

Ah, my specialty! May I introduce myself as KF4ZHL, my ham call sign. Hopefully, I keep this simple enough. What you are likely picking up is a shortwave station. "Ghost" signals generally need to be from an AM "Amplitude modulated" station. They're quite common. Pick up any old cheap phone without a filter, wait for the dial tone to go off, and you'll probably be able to hear at least one or two faint radio signals getting picked up on the telephone wires. The reason is that amplitude modulated radio signals are the electronic (electromagnetic) equivalent of sound vibrations. An AC electricity in a piece of metal will emit EM waves at the frequency of the current running through it. Modulating the signal amplitudally means that you make the voltage of the frequency higher and lower to reflect the input signal from the voice/music. Since EM waves are generated by AC current, EM waves will induce current in the metal they hit too. It's just a very weak current because of the energy's diffusion over the broadcast area. Radio receivers amplify this tiny current. This just leaves the voltage differences to drive the speakers. The natural properties of many electronic items can mimic this effect on unintentional signals received on their metal parts. The station you hear is dependant on the signal strength and the frequency the item is most resonant with. Particularly strong AM signal sometimes don't even need amplification to drive a tiny ear bud speaker in a well tuned circuit, such as in a crystal radio.