This amplifier is useful for applications where a 10- to 15-W peak-envelope-power (PEP) signal is needed i
n the 420- to 520-MHz range. CI, C2, and LI form a matching network for amplifier Ql. L3, C3, and C4 form an output matching network for a 50- load. L2, R2, Dl, and R3 through R6 (with bias adjust Rl) form a biasing network for Ql. D2 and D3 provide polarity protection for Ql, which must be heat-sinked.