Hi I research about VCO for FM and best FM modulation with minimum harmonics is Wideband Colpitts VCO
"This wideband Colpitts VCO uses a series back-to-back connection of two SMV1232 varactors instead of a single varactor. This connection allows lower capacitance at high voltages, while maintaining the tuning ratio of a single varactor. The back-to-back varactor connection also helps reduce distortion and the effect of fringing and mounting capacitances.
The wideband Colpitts feedback capacitances C3, C4 were optimized to provide a flat power response over the wide tuning range. These values may also be re-optimized for phase noise if required.
The circuit is very sensitive to the transistor choice (tuning range and stability) due to the wide bandwidth requirement.
DC bias is provided through resistors R6 and R7, which may affect phase noise, but allows the exclusion of RF chokes. This reduces costs and the possibility of parasitic resonances which is the common cause of spurious responses and frequency instability."
I find one on internet , perhaps is professional but schematic is inquiring, im not sure it is good? can you help me to cheek and see is good? If if is god I wont tray build one for experiment .