INDIAN MST RADAR IN ST MODE - AN OVERVIEW

A highly sensitive MST (mesosphere-stratosphere-troposphere) radar ope rating at 53 MHz with an average power-aperture product of 7 x 10(8) W m2 has been established as a national facility at Gadanki (13.47-degre es-N, 79.18-degrees-E), near Tirupati. The system development has been accomplished in two phases. In the first phase, it was commissioned i n ST mode using partial system comprising one quarter of the Yagi ante nna array and 16 driver units of the transmitters providing an average power-aperture product of 4.8 x 10(6) Wm2. The ST mode operation has enabled not only to validate various subsystems of the radar but also to collect some interesting observations on the structure and dynamics of the ST region and also on the field-aligned F-region irregularitie s. A concise account of various technical aspects of the system includ ing off-line data processing and an overview on the experiments conduc ted under ST mode operation are presented.