A conversation with a friend made me suddenly recall that when I was a kid in the early 80’s, we could occasionally hear a faint rendition of the major local AM station coming from the faucet of the kitchen sink. We lived just a mile or two from the broadcast antenna.
It was very faint and had a spooky sizzling quality, but it was unmistakable. Our wall-mounted telephone also picked it up, but more distinctly. I can understand the telephone noise reason, as there’s an amplifier and speaker. But a faucet? How?
In: Physics
AM is produced by mixing a carrier signal (frequency of the radio station) and a modulating signal (audio) through a non-linear conductive element i.e. element in which the relation between voltage and current are not linear. A diode is the more commonly known non-linear element, which is often the element used to illustrate an AM modulator or demodulator in electronic drawings.
To demodulate, you do the reverse operation, so you feed your AM signal through a non-linear element which output your carrier and audio signal (and other components).
Your sink is a non-linear element.
It demodulates the AM signal which produces the audio signal, which is probably translated to sound through vibration since it’s wall is quite thin.
Latest Answers