It is basically a diode detector followed by a high-gain audio amplifier. It picks up everything at once!
detector uses a biased Schottky diode for excellent sensitivity and bandwidth; the detector will detect signals from below the AM broadcast band up to the microwave bands. The number of interesting signals is surprising; it is fun to drive around listening to the numerous strange sounds. By trying different antennas and locations, this receiver has picked up AM radio stations, FM stations, TV video (buzz), car lock transmitters, cell phones, and even the microwave oven (a whoosh-whoosh sound as the microwave spreader rotated).
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