This circuit for receivers was found in an American documentation from the 90's. The circuit operates at up to 500 MHz. The integrated circuit used is uncommon nowadays.
This blocking oscillator configuration was found in a 1964 American book. The circuit can be...
This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is...
This transmitter, indicated for espionage applications, is permanently powered by the power grid....