The C band is a band of frequencies used
for terrestrial radio relay and satellite transmissions. The band is
commonly called 6/4 GHz to illustrate that the uplink frequencies
are around 6 GHz and the downlink frequencies are around
4 GHz. The band of frequencies are between 5.925-6.425 GHz
for uplinks and 3.7-4.2 GHz for downlinks.