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 oscillator for testing resonant circuits was found in a Radio Electronics magazine from June...
This circuit, suggested by an old American publication, allows you to use the AM radio antenna of a...
This circuit limits (clip) the intensity of a signal, according to the setting of P. The circuit is...