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.
This is the typical circuit of an FET amplifier stage in the common source configuration. The circuit is...
This is the conventional version of capacitance multiplier with operational amplifier that appears in...
This transmitter with counterphase oscillator was obtained in a documentation from the 90s. The...