This circuit was obtained from an American documentation from the 90's. The components can be changed, and a power step can be added for greater sound volume.
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...