This circuit was suggested by General Electric in a 1969 documentation. The transistors are of the time and the power supply is not given. Note the high supply voltage.
This circuit uses an MW radio tuned to around 540 kHz to detect atmospheric signals, for example, from...
This project was found in a 1982 publication. It is a small transmitter that can send signals from...
This circuit is from a 1960 book by Hugo Gernsback. The transistors are germanium from the time....