In February 1982 the first successful trial of a frequency modulated, interrupted, continuous wave (FMICW), monostatic ground-wave radar for sea backscatter studies was carried out. Since then data have been collected in a number of different meteorological conditions over a range of HF frequencies. The data are presented and compared with simulated Doppler spectra obtained by evaluating the integral equation, which relates the sea backscatter spectrum to the ocean wave directional spectrum (Barrick 1972). The dynamic range performance of the system is as good as or better than has been achieved by pulse radars currently in operation. Good agreement with the theoretical formulation is demonstrated