The Doppler beam-swinging (DBS) and the spaced antenna (SA) techniques for radar wind measurement are compared on theoretical and practical grounds. It is shown that the information content is similar for both techniques and that errors introduced by horizontal variations of the vertical wind field affect both equivalently. A radar equation for a bistatic radar with close transmitting and receiving antennas is derived, and it is shown that the backscattered power is proportional to an equivalent area. The equivalent area is equal to the antennas' physical area for a monostatic radar and is twice the area of the smallest antenna in the limit of one antenna being much larger than the other. Other factors affecting the techniques' sensitivity and accuracy are discussed. VHF radars operating at about 50 MHz should give similar sensitivity using both techniques, but for UHF wind profilers the DBS method is preferable.