Free circuit schematics - wiparat.com

This circuit uses a small microphone to capture the sound and some transistors to generate radio waves that can be picked up by a FM receiver like a car stereo.
From left to right, the first part is the microphone and some resistors to get it working. Next we have a capacitor and the first transistor, [...]

The circuit is the same as the V7 VHF FM transmitter, but with a few small additions. TR1 (BC547) is an inverted Hartley oscillator which is based on the inductor manufactured PCBs. This makes it stable and megga-setable throughout the VHF FM band (76MHz to 119MHz) and the BB105 varicap voltage is tuneable over about [...]