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 circuit is one of many that the reader can find in this section for testing crystals. The...
This circuit was found in a Philips documentation from 1966. Its purpose is to drive the solenoid...
This sinusoidal oscillator is suggested by Texas Instruments' Linear Circuits Applications, using a...