Here is miniFM transmittercircuit. TheFM transmittercircuit using 2 transistor. Audio sensitivity is very good when used with an ECM type microphone insert. This smallFM transmitteruses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The FM transmitter coil is four turns of 18swg wire wound around a quarter inch former.
Here is a schematic mini FM transmitter:
Source: http://www.hqew.net/circuit-diagram/Mini-FM-Transmitter-Circuit_3354.html
