Here’s basic RF amplifier design that will happily run all day at 8W (I even pushed it to 14W!).
This is the circuit I used in this amplifier here: RF amplifier construction for an FM transmitter – the cheap way
But I wouldn’t recommend running it over 8W and you’ll need to use a heat sink or bolt to metal chassis. I used the 2SC1971 from Mitsubishi (the Mitsubishi branded ones seem to output significantly more power). Data-sheet here.
Alex
Hiya, couple of questions if I may…. What kind of input (mW) would you suggest to drive it ? and what size wire for the coils, and also coil i/d and length ?
Cheers
Alex
swr
The 2sc1971 can take as little as 300mw to give a good output, if your winding your own coils I suggest using the end of a chuck key from a drill will be a good match for the diameter of toko coils.