This receiver of two transistors for the 3.5 MHz band was found in a circuit manual from the 80's. The coil data are found next to the diagram and the transistors can be general purpose PNP.
In this circuit, from a 1977 publication, we have the traditional version of a filter that rejects 1...
The integrated circuit used in this application is uncommon today. However, the basic...
This physical line servo control uses components that are not currently common. The circuit is from...