The microwave emission spectrum is obtained for the discharge during collision of two oppositely charged water drops of equal size in the absence of an external electric field. The power spectra obtained for drops 1.00 and 1.50 mm in diameter covering the frequency range 3291-10.940 MHz show pronounced maximums and minimums, unlike blackbody radiation, which follows an f2 law where f is the frequency. These results imply that radiation from sparking drops is separate from the thermal radiation from clouds. The observed emission spectra agree well with the theoretical results of Atkinson and Paluch if the duration of the spark is taken to be 2¿109.8 s. The variation of radiated energy E with drop size d and charge Q is found at 9210 MHz to be E∞Q6.6/101.96d. For colliding drops of equal size the radiated intensity is dependent on the total charge neutralized between the drops and not on how the charge is initially distributed, even when one drop is initially uncharged. On the basis of the experimental results a simple cloud model is used to calculate contributions to the antenna temperature of a radiometer from (1) the electrical activity due to sparking drops and (2) the cloud liquid water present in the antenna beam. It appears feasible to utilize a dual-wavelength radiometer as a remote sensing probe to determine simultaneously the liquid water content and the electrical activity in certain types of storms.