The main focus of the radio astronomy facilities at IIA is on the observations of the Sun. The early observations date back to the 1950s at the Kodaikanal observatory of the institute. Continuous recording of the solar radio noise flux commenced in 1952 using a 100 MHz interferometer with Yagi antennas. A 20 feet paraboloid for observations at frequencies in the decimetre and metre wavelength range was set up on an equatorial mount in 1961. Work on an interferometric aerial for scintillation studies at 60 MHz was also started during this period. Under the Kodaikanal - Yale Project, recording of radio radiation from Jupiter at a frequency of 22.2 MHz was started using a phase switching interferometer. The custom-built 3 GHz wavelength radio receiver from the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia was put to use in 1965. Mounted on a 2 m paraboloid, it was used for regular solar patrol. In the early 1970s, small-sized antenna arrays operating at 25 MHz were used to obtain information on the radio bursts from the outer solar corona with high temporal and spectral resolution.
A.K.Das and B.N. Bhargava. Nature, 1953 Vol.172, p855