This receiver for a modulated light intercom was found in a 90s Elektor. The audio amplifier can be replaced by an equivalent. The sensor can be any phototransistor.
The main feature of this RF oscillator that operates in the range of 100 to 800 kHz is its low...
Many people currently use the bicycle as a means of transportation and leisure in large cities....
In this radio the coil can be made with 70 + 30 turns of wire 28 to 32 in a cardboard or PVC tube...