Raindrop size distribution profiling by laser distrometer and rain attenuation of centimeter radio waves

80-85The paper describes system design of laser distrometer, its calibration process and profiling of raindrop size distribution (RSD). Here, raindrop signature is extracted by allowing the drops to pass through a controlled field of view of a sensor. A laser beam works as signal source, phototransistor as detector-cum-amplifier and optical fibers as trans-receiving ports. RSD profiles and rain rate at different weather conditions have been presented. Specific raindrop attenuation of line of sight radio signals at 10 - 30 GHz of various drop diameters is then calculated by using standard attenuation equations and model values of scattering functions. Finally, the rain attenuation magnitudes are compared with those given by a model framed earlier [Timothy K I, Sharma S, Devi M & Barbara A K, Model for estimating rain attenuation in frequencies range 5-30 GHz, Electron Lett (UK), 31 (17) (1995)]