This circuit is from a 90's documentation. The circuit is simple, as it uses only two transistors, and the control is done by pressure switches. The indication is done by LEDs.
This converter converts a signal in the 200 kHz to 3.8 MHz band into frequency signals that can be...
This is the receiver for the previous circuit. The audio amplifier supports equivalents. The...
This circuit is from Radio Electronics from February 1987. The frequency is given by the crystal that...