Uses
Symphonie was the forerunner for numerous telecommunications services. Its prohibition on commercial use may have paradoxically induced a larger program for experimentation of space telecommunications than ever before – both in the number of participating countries and diversity of field applications. As an example of the extent of its use, 40 countries participated in links via Symphonie A and B (east-west and north-south) – from Quebec to Argentina, from Finland to Reunion Island and from China to Indonesia. The Symphonie A and B experiments may be divided into two types:
- Humanitarian, cultural and educational experiments
- Technical and scientific experiments
To these types operational experiments may be added, notably for links between metropolitan France and its overseas departments for telephony and television via satellite. From this viewpoint Symphonie was a forerunner of the French national programs Telecom-1 & 2 and TDF 1 & 2, and the German programs TV-SAT and DFS Kopernikus. The wideband transponders, with their operational flexibility, made it possible to test all-access techniques (single or multiple) and modulation: FDMA (frequency sharing), TDMA (time sharing) and SSMA (spread spectrum). Symphonie terrestrial stations with antennas of various diameters from 16 to 2.2 meters (fixed, portable and mobile) contributed to the renown of the programme around the world. Several demonstrations were:
- Links between United Nations headquarters in New York and Geneva and the UN Blue Helmet squadrons in Jerusalem and Ismaïlia – inaugurating the future communications mode VSAT (very small aperture terminal), using small-diameter ground antennas
- Educational television in Africa, particularly in Côte d'Ivoire and Gabon
- Intercultural exchanges via teleconferencing, telerehabilitation and telemedicine, notably between France and Quebec
- Occasional tele-transmission services (emergency links to disaster areas for the Red Cross, sports reporting and so on)
- High-speed, bidirectional links between computers – a forerunner of transcontinental data communications and the Internet
- Synchronization of atomic clocks on an intercontinental scale, to obtain a very high stability of universal time – a forerunner to navigation and positioning satellites GPS and Galileo
- Regional-level tests for mixed analog and digital television and radio broadcasting (now used in many countries – for example Iran, India and China)
One opportunity to demonstrate Symphonie's utility in 1978 was not used; it could have been utilized in Kolwezi (the intervention of French troops in Zaire to protect Europeans living in Katanga), if the French chiefs of staff had followed the above-mentioned UN example rather than calling upon logistical support from the United States.
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