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.
Found in a 1963 documentation, this circuit employs germanium transistors of the time. Transformer and...
In the figure we have a way of receiving ultrasonic signals of a single frequency using a PLL 567....
This traditional circuit generates a 200 Hz sinusoidal signal. The frequency depends on the...