The article presents a source producing high-power ultrawideband electromagnetic pulses. The source includes a generator of monopolar pulses, a bipolar pulse former, and a combined ultrawideband transmitting antenna. Monopolar 150-kV, 4.5-ns pulses are transformed into bipolar 120-kV, 1-ns pulses, which are emitted by the antenna. The pulse repetition rate of the setup is up to 100 Hz. The peak power of the source is 170 MW as measured with a TEM-type receiving antenna having 0.2–2 GHz passband. The pattern width of the transmitting antenna at a half-level of peak power is 90° and 105° for the H- and E-planes, respectively. The electric field strength measured 4 m from the transmitting antenna in the direction of the main radiation maximum is 34 kV/m.