Bragg scattering mechanism has been probed by a fully digital ultra-high-frequency (UHF) radar system. The system is based on studies of UHF radio wave (340 MHz) scattering from small-amplitude water waves. First-order radar cross section Doppler spectra have been measured. Comparing them with theoretical models, good agreement has been found. The amplitude ratio (dB) of the cross section between incident and reflected waves is 14.7 dB, and its deviation is 0.68%. The expectation of the normalized Doppler frequency shift of first-order peaks is 0.9850, and the deviation is 1.5%.