The range of this FM vfo adjustable transmitter circuit with a 9V battery is about 300 feet.
C3,C4 10uf Electrolytic Capacitor
C5 3-18pf Adjustable Cap
R1 270 Ohm
Q1, Q2 2N2222A
MIC: Electret Microphone.
MISC: 9V Battery Snap, Wire For Antenna
L1 and L2 are 5 turns of 28 AWG enamel coated magnet wire wound with a inside diameter of about 4mm. The inside of a ballpoint pen works well (the plastic tube that holds the ink). Remove the form after winding then install the coil on the circuit board, being careful not to bend it. C5 is used for tuning. This fm transmitter circuit operates in the normal broadcast frequencies (88-108MHz). Q1 and Q2 can also be a 2N3904 or something similar.