Effect of Geophysical Disturbances on Ionospheric Radio Wave Propagation and Emergency Communication

Some results of a study of the effect of geophysical disturbance due to solar flares, thunderstorms and meteor showers on the ionospheric radio wave propagation characteristics in the entire frequency range of radio communication ranging from VLF to HF, are presented. The results reveal that a fadeout in one band may be accompanied by an enhancement or no change of signal level in other band, and thus indicate the possibility of evolving an interband frequency diversity system involving VLF, LF, MF and HF bands to cope with the fadeouts associated with different geophysical disturbances.