The carrier frequencies for AM operate from 530 kHz to 1610 kHz. Many superheterodyne AM radios use a demodulation circuit designed for 455 kHz. When the listener tunes in a station, an oscillator ...

This simple receiver topology encouraged home constructors to do it themselves, and many did. All later television receivers were of the superheterodyne type ... between 30 kHz and 90 kHz. And herein ...