It can actually be much simpler these days using a minicircuits vco (50R output)
and a pll chip, not a lot else to it really.

10mW would give you a fair old range line of sight.

Stick a minicircuits ERA 80mW device (4 legs, 50R in, 50R out) on the output of
the vco if you want a bit more umpf.

Just as easy on 70cms or the unlicensed 458MHz ISM band, same for 23cms and 13cm
or 2.4GHz ISM band. It's SO EASY these days with the building blocks you can
get.

Clive