This circuit of the 80s makes use of an operational one of the time. It can be designed with modern operationals and must use a symmetrical power supply.
This simple field strength meter was found in a 1967 documentation. The transistor is germanium, and the...
This is yet another version of the light-controlled oscillator that can be found on this website. This...
Found in a 1969 documentation, this circuit for the 20 MHz band does not use a transformer. The circuit is...