The following diagram is a simple Small FM Transmitter circuit which uses small transmitter Hartley type oscillator. This transmitter designed to transmit voice input signal for small range transmission (for example: wireless microphone).
Normally the capacitor in the circuit reservation might be connected to the base of the transistor, but the ability of VHF base of the transistor acts as a short circuit, so that in fact it still is. The coil is four turns of wire wound around a quarter inch above 18swg. The aerial tap is about an hour and a half laps from the end of the offer. Audio sensitivity is very good when used with an ECM type microphone insert.
Small FM Transmitter circuit circuit source: http://www.zen22142.zen.co.uk/Circuits/rf/davidtx.htm