FABRICATION AND TESTING OF COAXIAL S-BAND MIXER

Abstract

A multipurpose satellite 'INDIAN NATIONAL SATELLITE-INSAT--1' for the domestic Telecommunication and Meteorological survey with capability of nation wide Direct T.V. broadcasting is going to be launched [1]. As for as direct T.V. broadcasting is concerned INSAT-1 system has capability to provide two direct broadcasting T.V. channels in S-band (2.5 GHz), each channels is 36 MHz wide, having the carrier frequencies at 2575 MHz and 2615 MHz, with a guard band of 4 MHz. In addition to the above, there are 12 channels for Telecommunica-. tions and a data channel for relay of meteorological, hydrological and occenography data. From the past experience of Satellite Instructional Television experi-ment (SITE) with US NASA ATS-6 satellite, it has been found that direct reception sets with G/T ratio of 8«2 dB/oK are required for good performance in primary coverage areas. This can be achieved by a 12 ft. dia. chicken mesh antenna and a receiver noise figure of better than 4.5 dB. A Direct reception set is the one which can receive the programme relayed from the satellite. These sets differ from the ordinary sets, because the received Radio Frequency Signals is not in conventional VHF or UHF band, but in 8-band (Microwave region) .