C-Band ("Compromise" Band)
C-Band is a part of the electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz.
C-band is primarily used for satellite communications, generally with downlink 3.7–4.2 GHz, uplink 5.9–6.4 GHz, usually 24 36-MHz transponders on board a satellite. Most C band satellites use linear polarization, while a handful (particularly older Intelsat satellites) use circular polarization.
Typical antenna sizes on C-band capable systems for home reception in North America range from 7.5 to 12 feet (2 to 3.5 m). In other regions of the world, such as Europe and parts of Asia, considerably smaller antennas can be used due to high-powered satellites in this band and more distance between satellites in the orbital arc (compared to the two-degree spacing common over North America).
C-Band usage is less common in Europe, where KU Band has traditionally dominated. In many parts of the world, C-Band is often used to cover a very broad area, for example all of Africa or China. Indeed, many C-Band satellites have "global" beams with gigantic coverage areas. C-Band is considered to be more resistant towards rain fade.