CUSTR- A VHF phased array radar for observation of atmospheric dynamics and ionospheric plasma irregularities.

A VHF phased array radar for atmospheric dynamics observation is installed at the University of Calcutta, Kolkata. The Calcutta University Stratosphere-Troposphere Radar (CUSTR) operates at 53 MHz with 475 three sub-element Yagi-Uda antenna array. The CUSTR system is a high-power fully active phased array system with a dedicated 2 kW solid-state Transmit-Receiver Module (TRM) attached to each antenna, providing a total peak power of 950 kW with 47.5 kW average power at 5% maximum duty ratio. The system provides electronic beam steering capability to steer the beam 360° in azimuth direction with a maximum off-zenith angle of 40°. The array is configured with 25 sub-arrays and operates either in a combined mode in Doppler Beam Swinging or in Spaced Antenna mode using a multi-channel digital receiver system. The TRM has been designed to provide a very short pulse of 0.5 µs and a long pulse of 128 µs. The system description along with the initial scientific observations such as atmospheric boundary layer, troposphere-lower stratosphere wind measurements along with preliminary wind validation, mesosphere echoes and ionosphere irregularities are presented.