TABLE OF CONTENTS End users are connected to an earth station at their location, whether it is a personal system or a network serving multiple users. This earth station provides two-way communications up to the satellite. The space station relays the two-way information to another earth station that provides the services, whether it is Internet services, telephone, fax, video or music (see Figure 10 2).
Four different bands of operation are used for satellite communications. The lowest band is called the L-band. It operates with an uplink at 1.6 GHz and a downlink at 1.5 GHz using a narrow bandwidth. The next band is the C-band and operates around 6 GHz for the uplink to the satellite and 4 GHz for the downlink from the satellite to the ground station. The next band, which is generally used by the military, operates in the X-band and operates around 8 GHz for the uplink and 7 GHz for the down-link. The next band, which has become popular for telecommunications, is the Ku-band and operates around 14 GHz for the uplink, and 11 to 12 GHz for the downlink. The highest band of operation, the Ka-band, is becoming popular for broadband communications and other applications. This band operates at 30 GHz for the uplink and 20 GHz for the downlink. The Kaband provides a much higher bandwidth for high-speed data and allows for more simultaneous end users. A summary of the...
