This thesis deals with the theoretical analysis of the effect of the water droplets in the atmosphere on the propagation of a linearly polarized plane wave. These effects are (1) scattering - it is found that the scattered power is proportional to the sixth power of the radius of the droplet, also the scattered power varies as the fourth power of the frequency. (2) Absorption - it is found that the dielectric loss is much greater than the conductivity loss in the frequency range 10 M Hz. to 300 M Hz. The absorbed power is found to be much greater than the scattered power in the frequency range 10 M Hz. to 300 M Hz. Multiple scattering is neglected because scattered power is very small compared with the power absorbed. At the end of the thesis an expression for the attenuation constant is derived for homogeneous distribution of rain-drops of particular size falling at a particular rainfall rate. / M.S.