This simple circuit measures the strength of a radiated signal from a transmitter. It is commonly used by model airplane builders to check whether their transmitter are really transmitting the radio ...
A simple fm radio transmitter circuit which covers frequencies from 88 to 108 MHz. It is built with 3 transistors: BC109, BFR91A and BFR96S. It is quite stable and the output power is around 200 mW.