C Band & Ku Band Satellite Frequencies
Which of them is better? Why?
Many mobile operators nowadays are using Very Small Aperture Terminal (VSAT) to provide coverage in remote areas & enhance their network coverage. VSAT technology needs a frequency for operation, as any other mobile communication technology. The two main bands for VSAT communications are C-Band & Ku-Band. The question is which of them is better and when to use each of them? Here you will find a C band Ku band Comparison.
C-Band & Ku-Band have their pros & cons. We will discuss the pros and cons of the two frequency bands here to provide a clear idea of each one’s suitable use.
International Telecommunication Union (ITU) is the worldwide frequency regulator. ITU initially defined C-band to be the first satellite band and its frequencies range from 4Ghz to 8Ghz. This range of frequency is also used widely by terrestrial microwave backhaul links nowadays, especially because the sub 6GHz band is free of license in many countries all over the world. This resulted in a great interference problem between C-band & terrestrial backhauling links. Thus, ITU started to define new frequency bands as Ku-Band.
On the other hand, signals in C-band are less focused compared to higher satellite frequencies such as Ku-Band. This is due to the longer wavelength in C Band. Less focused signals means that these signals are less affected by rain (a phenomenon known as rain fade of satellite signals). The attenuation on C-band signal due to rain fading ranges from 0.4 dB to 1 dB only. Moreover, these less focused signals can provide wider range of coverage. However, these signals need larger dish size ( e.g. 2.4 , 3 or 3.7 meters in diameter), so that they can be received from the satellite. Thus, C-band requires more expensive equipment compared to Ku-Band (more Capital Expenditure “CAPEX”).
Unlike C-Band, Ku-band frequencies are dedicated for satellite communication only. This solves the problem of interfering with terrestrial microwave backhaul links. Moreover, Ku-Band is characterized by its high powered signals compared to C-band. Thus, smaller dishes can be used to achieve the same distance as C-band and the KU band radio transmitter also requires less power. Normally, 0.9, 1.2 or 1.8 meter dish is used for Ku-Band applications. This can save great CAPEX and makes Ku-band suitable for small networks. However, Ku-band is more sensitive to rain fade and the attenuation due to rainfall can be up to 10 dB.
When to use each of C-band & Ku-band:
C Band :
- C-band is preferred in some locations where rainfalls are heavy, as the situation in tropical regions of Africa.
- From a commercial point of view, C-band is better for satellite applications that need larger bandwidth. This is because the license fees for C-band bandwidth are cheaper than Ku-band ( less Operational Expenditure “OPEX”)
- Ku-band is preferred for cases where there is a limited area for installation, because a smaller dish size is needed and it is easy to install.
- From a commercial point of view, Ku-band is better for satellite applications that need smaller bandwidth, as the equipment is cheaper than C-band.
Both C-band & Ku-band have their uses in satellite applications. Both of them can provide accepted QoS and communication speed. ITU has also introduced higher frequency bands such as Ka-band and X-band, which have lowered the load on C-band.