Hi:
I fail to see how this circuit can properly work. I am assuming that there is a connection between R5, and C4, C5, and L2; also, I am assuming a connection between R1, R2, R6 and R3 and the gate of Q1.
My issues are:
1. R5 seems to be a very high value to supply any kind of power to the drain of the FET.
2. The values of R1, R2, R6, and R3 would probably turn the MOSFET into a hard ON state. Typically, they should supply just enough bias to overcome the Vth of the MOSFET.
3. I am assuming that you are using the term "Linear" as some RF people use to mean a power amp. The circuit should be operating in class C (or, at most, in class B), which is quite OK for FM.
Thanks,
Jem