Commercial and military satellites that employ Satellite VSAT communication operate within four Radio Frequency (RF) bands. Each of these frequency bands is distinct, with its own uplink (Tx) and downlink (Rx) frequencies and RF components (LNB and BUC), making them well-suited for specific applications.
C Band
uplink 5.925-6.425 GHz
downlink 3.7-4.2 GHz
The C band is typically used for voice and data communications, as well as backhauling. Despite its relatively weaker power, it requires a larger antenna, usually exceeding 1.8m (6ft) in size. Nonetheless, the C band’s lower frequency range makes it less susceptible to ground-level weather-related disruptions, making it more resilient under adverse conditions.
X Band
uplink 7.9- 8.4 GHz
downlink 7.25 – 7.75 GHz
The X band is primarily used for military communications and Wideband Global SATCOM (WGS) systems. With fewer satellites orbiting in this band, there is a greater separation between adjacent satellites, making it well-suited for Comms-on-the-Move (COTM) applications. Furthermore, the X band’s lower frequency range renders it less vulnerable to rain fade than the Ku band, which translates to greater performance under inclement weather conditions.
Ku Band
uplink 14 GHz
downlink 10.9-12.75 GHz
The Ku band (K band Under) is typically utilized for consumer direct-to-home access, distance learning applications, as well as retail and enterprise connectivity. Due to the higher frequency range, the necessary antenna sizes, which range from 0.9m to 1.8m (~6ft), are much smaller compared to C band antennas. Consequently, Ku-band networks can achieve higher gain with smaller antennas than C-band networks. However, networks operating in this band are more vulnerable to rain fade, particularly in tropical regions, and so ACM is used to prevent service outages.
Ka Band
uplink 26.5-40GHz
downlink 18-20 GHZ
The Ka-band (K band Above) is mainly employed for two-way consumer broadband and military networks. Ka-band dishes are generally smaller, with diameters ranging from 60cm to 1.2m (2′ to 4′). The transmission power in this band is significantly greater when compared to C, X, or Ku band beams. However, due to the higher frequencies utilized by this band, it can be more susceptible to signal quality issues resulting from rain fade. To overcome this issue, ACM is again used to help mitigate the effects of rain fade. O3b Network satellite service utilizes Ka-Band for its connectivity.