Dr. Sat discussion forum
Television sources => Free to Air (FTA) Satelilte Television => Topic started by: DrSat on March 23, 2016, 11:40 am
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A fair amount of people always ask us what are the differences between C and Ku band and the benefits of each. Some people believe that C band is old technology as it started being used in residential locations back in the late 1970's while Ku band only started getting used in the late 1980's. However, the truth is that in addition to Ku band, C band is still currently used up to this day as it has a few advantages over Ku band.
C band
The reception of C band satellite requires a dish of at least 1.8m (6 ft.) for reception of most channels but a dish of at least 2.4m or larger is highly recommended as anything smaller will be unable to properly focus on a single satellite. Moss t satellites in the sky are evenly spaced every 2 degrees which can cause interference on undersized dishes if any of the two adjacent satellites have transponders using the same frequency and polarity. 2.4m or larger satellite dishes are classified as being "2 degree compliant" so they don't suffer from this issue.
C band uses a downlink frequency range of 3.7 – 4.2 GHz for reception while broadcasters use an uplink frequency of 5.9 – 6.4 GHz and has the following advantages & disadvantages:
Advantages: - Higher reliability than Ku band as signal is almost practically immune to rain fade
- Less demand for satellite space means cheaper costs for broadcasters to rent a C band frequency v.s. Ku band
- Due to the above two factors, permanent satellite channels typically favor the use of C band for distribution of their signal(s)
- The lower frequency band being used means that it is easier to find a C band signal when aligning your dish
Disadvantages: - Larger satellite dish required which is often time consuming and harder to install
- More expensive reception and uplink equipment
- Potential interference from the neighboring licensed 3.65 GHz band used for fixed wireless Internet in certain areas.
Ku band
The reception of Ku band satellite requires a dish of at least 45 cm (18 inches) but a dish of at least 75 cm or larger is highly recommended as anything smaller will be unable to properly focus on a single satellite. Most satellites in the sky are evenly spaced every 2 degrees which can cause interference on undersized dishes if any of the two adjacent satellites have transponders using the same frequency and polarity. 75 cm or larger satellite dishes are classified as being "2 degree compliant" so they don't suffer from this issue.
Ku band uses a downlink frequency range of 10.70 – 12.75 GHz for reception while broadcasters use an uplink frequency of 14.0 – 14.5 GHz and has the following advantages & disadvantages:
Advantages: - As smaller satellite dishes can be used, installation is easier and less time consuming
- Less expensive reception and uplink equipment
- No interference concerns from terrestrial fixed wireless Internet or other sources
- Due to the above two factors, temporary satellite channels typically favor the use of Ku band for distribution of their signal(s)
Disadvantages: - Higher demand for satellite space means higher costs for broadcasters to rent a Ku band frequency v.s. C band
- Signal is often disrupted during a heavy rain downpour due to water attenuating the higher frequency band being used
- The higher frequency band being used makes it a bit harder to find a Ku band signal when aligning your dish