This is a demostration of my radio receiving the "indiglo" beep signal from my Casio Databank Watch on a frequency of 182 kHz which was found to be the strongest ever.
MORE INFORMATION: Most of the indiglo lamps inside the watch do and will emit RF emissions but not that strong. The main
reason why this is demostrated is that indiglo lamps carry an RF emission of harmonic noise (that sounds like a beep when pressed) over a broad range of frequency with out a tuned L/C circuit cause the lamp however is an untuned noise transmitter. The only way to keep on transmitting but on a single channel you will need something like a loop antenna or coupler with a capacitor that is connected in parallel with the circuit, like a crystal set radio just without the germanium diode detector. Connect a long wire the part of the coil and a maybe a ground and you will be able to transmit on on frequency like a homing beacon. Still a watch like this is not ment for sending out signals, but something has to give off the light and the noise. Soon engineers will find a way to reengineer the Indiglo light to produce less noise, maybe last longer to keep the battery from going dead.
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