The phenomenal success of the Satellite Instructional Television Experiment (SITE) conducted in India followed by similar experiments conducted elsewhere in the Appalachian Region, Rocky Mountains, Alaska, Canada, China and Latin America in the mid seventies and early eighties, clearly established the tremendous potential of using satellite TV for educational purposes (Rao 1987). It is very satisfying to note that operational beginning of satellite based distance education facility is already making a significant impact in Indonesia, providing an effective educational system to the sparsely distributed population in 14,000 individual islands stretching across a distance of over 5000 Km, many of which are inaccessible mountainous or jungle terrain. Successful use of PALAPA satellite in Indonesia, INSAT in India and AUSSAT in Australia have prompted other developing countries like Brazil, China and Mexico also to develop their own satellite based educational system. Extensive use of satellite medium in China provides 31 hour adult educational programmes every day to 30 million people annually through 6300 TVRO earth stations and more than 50,000 learning centres.
Most dramatic impact of INSAT has been in the rapid expansion of TV dissemination in the country through installation of more than 600 TV transmitters and use of a large number of direct reception community sets in sparsely populated areas, for providing access to over 80 per cent of India’s population, through national and regional transmissions. INSAT is being extensively used for Educational TV broadcasting with about 100 hours of programme per month to over 4000 schools and colleges. An effective educational system requires not just a one way system of instruction but a two way interactive communication system enabling the target audience to ask questions and obtain clarifications from experts, in real time. Special inexpensive talk back facilities have been developed within ISRO to promote this activity in the country and a number of selected large scale experiments aimed at improving the level of understanding of rural people, providing refresher courses to industrial workers in cities and specialised education to schools and colleges were conducted to demonstrate the effectiveness of the satellite media for imparting interactive education (Rao 1995b). Recognising the acute need for eradication of illiteracy, particularly in the rural areas, ISRO has conceived of dedicated GRAMSAT satellites (Rao 1993) (Fig. 8), carrying six to eight high powered C-band and Ku-band transponders which together with video compression techniques can disseminate region and culture specific audio visual programmes of relevance in each of the regional languages through rebroadcast mode on to an ordinary TV set.
Vast improvements in technology have made it possible to reach millions of homes with antenna dish sizes as small as 90 to 45cm in ku-band. The recent upsurge in video compression technology now enables several TV channels to be carried on a single transponder. Availability of about 150 channels from a single satellite location can entirely change the complexion of home entertainment through direct to home television broadcast. Video-on-demand which includes specific group interest programmes in addition to general entertainment programmes, allows individuals to choose and even manipulate programmes of their choice. What was cost prohibitive yesterday has suddenly become affordable today with the availability of TV using only a small space segment resource in an economic way which can have a dramatic impact on educational and developmental services.