Radio Band Ku Frequency

Ku-band: 12-18 GHz satellite communications

The Ku-band runs from 12-18 GHz, which works out to wavelengths of roughly 1.67-2.5 cm (λ = c / f). You'll find it sitting between the lower C-band (4-8 GHz) and the higher Ka-band (27-40 GHz). Most of the satellite TV and broadband you encounter rides on this band. A common split puts 11.7-12.7 GHz on the downlink and 14.0-14.5 GHz on the uplink.

Next to C-band, Ku lets you get away with much smaller dishes. A 60-90 cm parabolic is plenty for home use, since antenna gain grows with (D·f/c)². What you give up is rain tolerance. Liquid water absorbs a lot more energy past 10 GHz, so a heavy downpour can knock the link out for a while ("rain fade").

Applications

By far the biggest use is DTH (Direct-to-Home) satellite TV. SES, Hispasat, StarOne, Sky Brasil and DirecTV all run Ku-band fleets. The band also carries VSAT corporate networks, maritime and aeronautical broadband, and the satellite trucks that news crews park outside. SpaceX Starlink leans on it too, using Ku-band for the user uplink.

FAQ

Why is Ku preferred over C-band for home TV? The antennas are smaller and each beam carries more bandwidth, so installation costs less and a single transponder fits more channels.

How bad is rain fade in Ku? A normal link budget keeps 3-6 dB in reserve for it. Now and then a heavy tropical storm pushes past that and you lose the signal for a bit, but it comes back once the rain cell moves on.

Is Ku-band used by 5G? Not directly. Terrestrial 5G lives in sub-6 GHz and the FR2 mmWave range (24-40 GHz). Ku stays set aside internationally for satellite services so the two don't step on each other.