Study of ionospheric irregularities over near-equatorial station anantapur using VHF Scintillations

An essential component of the ionosphere is a small-scale electron density structure that causes scintillations (fluctuations in amplitude and phase) of radio waves on transionospheric links. The study of these radio wave scintillations plays an important role in understanding the basic mechanism responsible for the generation and movement of ionospheric irregularities and their characteristics. This knowledge is very much essential for planning and development of satellite based communication system and radar system. In this paper we present our work on VHF amplitude Scintillations recorded at 250.649 MHz from FLEETSAT satellite using i-com receiver during March-2005 to August-2006 at Anantapur (14.7degN, 77.7degE, and Dip 15.4degN) India, that have been analyzed to study Ionospheric irregularities during day time and night time. Also the role of geo-magnetic activity on the enhancement and suppression of Ionospheric irregularities during quiet and disturbed days are clearly depicted in our work. We also present the results of observation of the diurnal and seasonal variations in the occurrence of the scintillations. The obtained results are discussed in the light of recent observations.