Abstract
Laboratory measurements of the fluctuations in microwave backscatter from vibrating water drops freely suspended in a wind tunnel are given for drops in the size range from 0.30 to 0.52 cm in diameter. A discussion of the measurement technique along with experimental checks of the theory is presented. The average value of the changes in backscattered power due to changes in shape as the drops vibrate is found to be 2.8 dB and appears to be reasonably independent of size. Occasional transient excitation of drop vibrations produced changes in power as high as 9 dB. Changes of 4–5 dB were observed frequently.