Atmospheric radars involve large investments and it is necessary that
an in-built self-calibration facility is introduced for routine check
of the 'health' of the system. In India, an MST radar is currently bei
ng built at Gadanki near Tirupati (13.456-degrees-N, 79.176-degrees-E)
for studying the dynamics of upper atmosphere. During the first phase
the radar is operated in ST mode where it is to probe the atmosphere
up to heights of 25 km for vertical beam and 15 km for off-vertical be
am. A method similar to phase-switched interferometry has been devised
for calibration of ST radar and some results of the experimentations
carried out on the radar are presented. Using this method the beam poi
nting accuracy, the beam width and gain of the receiving antenna can b
e checked routinely.