This circuit is from a 1924 book by Gernsback. The receiver uses two tubes and listens to headphones. Power is supplied by battery with the indicated voltages.
Another way to increase the sensitivity of the circuit with the amplification of the sensor...
We found this circuit in the Radio Electronics magazine of January 1986. The frequency is given by the...
This circuit was found in the September 1984 issue of Radio Electronics magazine. The circuit is...