I just made a simple fm transmitter and now I am trying to understand the different components that go into it. I am mainly working on the right half of the circuit. I think that L2 and C5 are acting like an oscillator, C6 is just keeping it oscillating. But I have no idea what the diode is doing, or the base and collector parts, or the purpose of C4, C7, and C8. Thank you in advance for your help!