Repetitively pulsed generators of high-power high frequency pulses based on sealed-off discharge chambers with a hollow cathode are described in this paper. Pulses of length 100–800 ns and power up to 250 kW at a frequency of 120 MHz with a repetition rate of 100 Hz were obtained using the chamber equipped with a H2 source. Pulses of length 100–1300 ns and power up to 900 kW at a frequency of 120 MHz with a repetition rate of 100 Hz were obtained using the chamber of similar design and equipped with a N2 source. The chamber filled with H 2 proved to be more efficient compared to the chamber filled with N 2 .