This 1924 receiver uses a battery for the tube filaments and a high voltage battery for the amplifier and detector circuit. The speaker is kind of high impedance era.
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...