Complex sentence: Modern solid state transmitters will automatically reduce power when high SWR is detected, so some solid-state power stages only produce weak signals if the SWR rises above 1.5 to 1.
Split into simpler sentences: Modern solid state transmitters will automatically reduce power when confronted by a high SWR. Consequently, some solid-state power stages only produce weak signals if the SWR rises above 1.5 to 1.