This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
Found in documentation from the 1970s, this circuit for resistive loads uses a trigger...
This simple receiver for listening on the phone was obtained in a 1960 documentation. The circuit is...
This circuit was found in the 1989 Radio Electronics Experimenter edition. The circuit has the...