page_title: Telstar 1
section_title: History
hierarchical_section_title: Telstar 1 / History
caption_attribution_description: English: Huge horn antenna at the AT&amp;T Andover satellite ground station at Andover, Maine, USA, used to communicate with the first direct relay communications satellite, Telstar. Also used with the Relay 1 satellite. Built in 1961, it provided the first experimental satellite telephone and television service between North America and Europe. The antenna was 94 x 177 ft. (29 x 59 meters) , and weighed 340&#160;tons. To protect it from bad weather, it was enclosed inside a Dacron radome 160&#160;feet (49&#160;m) high, 210&#160;feet (64&#160;m) wide which weighed 30 tons. It was dismantled in the 1990s. This type of antenna is called a Hogg or horn-reflector antenna, invented by Albert Beck and Harald Friis in 1941 and further developed by David C. Hogg at Bell Telephone Laboratories in 1961. It consists of a flaring metal horn with a metal reflector mounted in the mouth at a 45° angle to the axis. The radio waves come from the satellite at a 90° angle to the horn and are reflected down the horn to the small building on the left, where they are received and amplified. The reflector is a segment of a parabolic reflector, so the antenna is equivalent to a parabolic dish fed off-axis. The advantage of this design over a standard parabolic dish is that it has very small sidelobes; that is, the horn shields the antenna from radiation coming from angles outside the main beam, such as ground noise, reducing the noise temperature of the antenna. Early satellites had weaker transmitters than modern satellites and required large antennas like this to communicate with them. Telstar was not in a geosynchronous orbit and passed overhead quickly in about 20 minutes, so the huge antenna had to be precisely steerable to track it across the sky as it passed. The antenna is mounted on a huge turntable in an altazmuth mount. Polski: Ogromna antena tubowa, 28,6 m x 59 m, w ośrodku firmy AT&amp;T w Andover (stan Maine), używana do łączności z satelitą Relay 1
context_page_description: Telstar 1 was a communications satellite launched by NASA on July 10, 1962, it was the satellite that allowed the first live broadcast of television images between the United States and Europe. It remained active for only 7 months, a much shorter service life than today's artificial satellites. Although it no longer works, it is still in Earth orbit.
context_section_description: The idea of transmitting information by means of satellites was hardly new. As early as October 1945, the mathematician and visionary Arthur C. Clarke published an article talking about it in the specialized magazine Wireless World. His idea was to take advantage of the immensity of space to transmit information, using a satellite system for this purpose. During the Cold War, the shock caused by the successful launch of the first artificial satellite, Sputnik 1, by the Soviets increased the United States' interest in aerospace research. Soon thereafter, the Americans began their attempts to launch orbital communications satellites for transmitting telephone, radio, and television signals.
  In December 1958, the United States successfully launched its first communications satellite, SCORE. Through it, then-President Dwight D. Eisenhower sent a Christmas message to the entire world. However, SCORE stayed in orbit for only a few months, its enormous surface area and very low Earth orbit forcing reentry after only 500 laps around the planet due to aerodynamic resistance. Also, SCORE relied on a passive reflector, which greatly reduced signal strength, since it did not amplify the signal before sending it back to earth.
caption: Huge horn antenna at the AT&T Andover satellite ground station at Andover, Maine.
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