This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is not an easy component to obtain and the power can be supplied with a single button cell.
Found in 1968 Mullard documentation, this circuit uses period components. The transistors are...
In the figure we have a modified multiplier circuit that can operate with the sextuplicator with...
This circuit converts signals from the 350 to 500 kHz band to the 4.36 to 4.5 MHz band, enabling...