Why do most solid-state transmitters reduce output power as SWR increases beyond a certain level?
To protect the RF output amplifier transistors✓Correct answer
To comply with FCC rules on spectral purity
Because power supplies cannot supply enough current at high SWR
To lower the SWR on the transmission line
Explanation
Reflected power from a mismatched load combines with the forward wave and subjects the output transistors to voltage and current peaks well beyond their normal ratings, so the radio's protection circuit reduces power to keep them within safe limits. Reducing power does not change the SWR, which is set by the load and the line.