A portable 50 MHz transmitter capable of 15 kW peak rf power output at up to 5 percent duty cycles is described. The transmitter and a system synchronizer, also described, are combined with a frequency-coherent receiver, an on-line minicomputer processor with oscillograpic display, and a novel collinear antenna to provide a highly portable VHF Doppler radar system. The system, complete with 5-degree azimuthal beamwidth antenna, weighs about 250 kg, and can be installed in remote locations in a few days. It has been used successfully in studies of equatorial and auroral ionospheric irregularities during the past several years.