Simple but high efficiency of this circuit is a Colpitts oscillator for VHF. Ideal for higher frequencies above 50 MHz, Colpitts oscillators are used for VHF parasitic capacitance of the circuit is in parallel with the feedback capacitance desired and causes no undesired spurious resonances which may occur with the Hartley oscillator. The circuit above is a VCO FM, it is a grassroots project with grounded feedback from collector to emitter. A Colpitts oscillator is a series of designs for electronic oscillator circuits using a combination of an inductance with a capacitor to determine the frequency. Make an Oscillator 50-300 MHz Colpitts Type Circuits Diagram