TABLE OF CONTENTS One of the important advantages of Ka-band, spot beam satellites is the capability to use very small, low-powered, low-cost, and high-data-rate user terminals. These terminals represent a paradigm shift for the application of communication satellites. An appreciation of this shift can be gained by tracing the history of satellite terminals.
The first commercial communication satellite application occurred in 1965, with the launch of Early Bird (INTELSAT 1) for international service. The standard antennas for this service were nearly 100 feet in diameter and used cryogenically cooled receivers. Only large common carriers could afford to build and operate these stations.
Since 1965, there has been a steady development of satellites with increased transmitter power and higher-gain antennas covering smaller geographical regions this allows the use of smaller-diameter terminals that are lower in cost. The early 1970s saw the emergence of domestic satellite services for Canada and the United States. These satellites which had medium-powered transmitters and concentrated that power on a smaller region (e.g., Canada or the United States) permitted the use of small (16 32 feet) and medium-sized (49 feet) earth stations. All of these satellites operated at C-band (uplink at 6 GHz and downlink at 4 GHz).
In 1976, NASA and Canada launched CTS-1 a high-powered Ku-band satellite (200 watt transmitter) designed to operate with small earth stations. CTS-1 proved the feasibility of service at Ku-band frequency (uplink at 14 GHz and downlink at 12 GHz) for video reception by small transportable terminals less than 3 feet in diameter.
