In this receiver the is formed by 80 turns of wire 28 or close in a ferrite rod. The handset is low impedance and powered by a standard battery.
Found in American documentation from the 90s, this circuit can use a BC548 instead of the original...
This circuit acts on the dynamic range of an audio signal, which can be useful for recording,...
This circuit doubles the frequency of a signal using a varicap. In this case, the input is 28 MHz,...