Estimation of spectral entropy for drone signal detection

I need to find spectral entropy of a signal that have drone sound and some other noises.

After localization of sound signal, how can i confirm that which frames of signal have drone sounds only.

For that i need to do spectral or frequency entropy.

My work flow is like that:

reading signal in matlab >> framing with 50% overlapping of window>> FFT and choose real part >>

How can i seprate Drone sound from other noises to get farmes of only drone sound using Entropy function.

Please researches guide me for this query.

Thanks in advcance.