We discuss three techniques for using a Doppler radar to deduce the vertical component of the wind velocity in the optically clear atmosphere. These techniques involve operating the radar antenna in three different modes : 1) scanning along almucantar circles (azimuth scans), 2) scanning along vertical circles (elevation scans), and 3) leaving the antenna fixed at the zenith. Results obtained from the Chatanika, Alaska radar facility are presented which show that below about 5 km altitude, all three methods give essentially the same results. Above this altitude, the first two methods become increasingly subject to errors arising from the effect of large scale atmospheric inhomogeneities and thus give less reliable vertical velocities. The zenith method gives accurate vertical velocities for all altitudes within its range.