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1945年,英国人克拉克指出:向赤道上空36000公里的静止轨道发射三颗相互间隔120°的卫星,有可能实现全球通信,如今已变成现实。人们可以通过卫星来传送电视节目,远程电视接收亦成为现实,这是众所周知。卫星广播电视,具有覆盖区城辽阔,覆盖区内场强较均匀,可以收到高质量图像,不受高大建筑物和高山的反射波影响,图象无重影等优点,因此越来越引起人们的关注,越来越引起个体家庭的兴趣。但是,由于星载发射功率小,电磁波达到地面的场强极其微弱,人们使用了大口径的抛物面天线以
In 1945, British Clarke pointed out: The launch of three 120-degree satellites in a static orbit above the equator over 36,000 kilometers makes it possible to achieve global communications and has now become a reality. It is well-known that people can transmit television programs via satellite and remote television reception has also become a reality. Satellite radio and television, with a vast coverage of the city area, the coverage area of uniform intensity, you can receive high-quality images, high buildings and mountains from the impact of reflection, the image without ghosting, etc., and therefore more and more cause People’s attention, more and more aroused the interest of individual families. However, due to the low on-board launch power and the extremely weak field strength of electromagnetic waves reaching the ground, people have used large-aperture parabolic antennas