The energy stored in a resonant cavity was extracted through four output ports and added in phase in a common line. Operation of a single switch provided synchronism and the power portions transmitted through the ports were combined in a waveguide turnstile junction. Estimation shows that the compressor peak power can reach a value eight times as much as the switched wave power, provided the output pulsewidth is shortened by the same factor with reference to the cavity double transit time. The performance of the X-band compressor prototype was investigated. Signals radiated through each of four output ports had identical envelope shapes and equal peak power values. The reflected wave did not accompany the power combining. The pulses of 1.2 MW peak power and 1.6 ns pulse width were obtained when the compressor was driven by the 50 kW pulse power magnetron generator.