What is Rain attenuation？
Rain attenuation, refers to attenuation caused when electromagnetic wave enters into rain layer, which includes the attenuation caused by
rain drops absorption and scattering.
Why there is Rain attenuation?
As there is dielectric dissipation in raindrops which will lead to signal attenuation. At the same time, the electromagnetic wave will be
reflected again and again by raindrops once they meet so that lead to signal attenuation.
How to decrease the influence of Rain attenuation？
To decrease the influence to satellite transmission system, the uplink stations of satellite transmission system mainly adopt solutions such
as improve transmission power, increase transmission antenna area etc. For the dual polarization transmission system with cross polarization
multiplexing, it needs to improve the system cross polarization isolation as possible. The most effective solution to decrease rain attenuation
of the downlink receive station is using antenna with larger area, LNB and receiver with higher sensibility etc. Meanwhile, there are some
additional solutions as below:
1. Fine adjust the antenna El &AZ angle and LNB Pol. Angle to the optimum position. Make the earth station antenna align to satellite as
possible. Although the live satellite adopts circular pol. Mode, the signal quality can be changed through fine adjusting the pol. So that
the received signal strength can be strongest.
2. If the antenna is installed outdoor, users can add a rain-proof shed for protection. For parabolic prime focus antenna, users can
addrain-proof equipment between feed system and LNB. Attention: The added rain-proof equipment cannot affect the signal reception.
It is only used to protect the rain from staying on the surface of panel antenna or feed film so that the rain attenuation can be decreased.