[en] The gyrocon is a high-power, high-efficiency amplifier that operates by deflection modulation of an electron beam. The spatial bunching can be better than the temporal bunching in a klystron, especially for high output powers and uhf frequencies. Soviet gyrocons have produced over 40 MW of pulsed power at 430 MHz and 250-kW cw at 181 MHz. The progress on the construction and testing of a 450-MHz prototype gyrocon is discussed. The maximum pulsed output power that has been achieved in the reporting period is 1 kW. Although these powers are significantly below the design goal of 650 kW, there is a good chance that the experimental program in FY-82 will result in increased output power