Degradation in satellite communication line quality due to solar interference
Solar interference occurring around the time of the spring and autumn equinoxes can cause degradation in the quality of satellite-based communication lines.
Antennas at ground-based stations are always positioned to face satellites in geostationary orbit. When the sun crosses this extended communication line between the antenna and satellite, the thermal interference that it emits can cause noise levels in the communication line to rise. This phenomenon, in turn, leads to degradation in reception C/N, and subsequent degradation in line quality.
Solar interference occurs for several minutes a number of times each day during any given period. However, the timing and duration of the interference, as well as level of line quality degradation, can vary depending on factors such as the location of the ground-based station and the size of the antenna. For receiving stations in the northern hemisphere, such interference occurs for several days just prior to the spring equinox and just after the autumn equinox. The situation is reversed for stations in the southern hemisphere. Solar interference occurs during the morning hours for ground-based receiving stations situated at longitudes west of the longitudinal position of the satellite, and during the afternoon for stations east of the satellite’s position