This circuit for the 1750 m band was published in the September 1989 Radio Electronics magazine. The range depends on the antenna system and receiver used.
The sensor of this circuit can be any phototransistor and the SCR can be the TIC106. The circuit and...
This multivibrator circuit uses only one gate and its frequency is controlled by the crystal. The...
The crystal in this circuit can have frequencies from 100kHz to 8MHz. Capacitor C2 adjusts the...