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 Popular Electronics from the 90's, this circuit uses common components and can be easily...
This circuit was found in a 1973 publication. The SCR may be the TIC106 and must use a heat sink,...
This circuit was obtained from my Mechatronics Sourcebook, published in the United States. In it...