The Spring, 2024 Solar Interference period will begin in late February to early March. The interference will occur from approximately 10:00am to 5:00pm depending on your location.
Solar Interference Background
The sun affects satellite-based communication by sun interference. This is caused by the sun passing directly behind a geostationary satellite as seen from a receiving earth station. This is demonstrated in Figure 1. This interference can cause degradation in quality of service or a complete service outage. Factors that affect this are the receive antenna size, its efficiency and the frequency band used.
For several minutes each day for several days during the equinox season (February/March and September/October), the sun passes through the equatorial plane. This is used by geostationary satellites. At these times, the apparent path of the sun across the sky takes it directly behind the satellites. This makes it appear in the beam width of a receive earth station’s line of sight.
Sun is an intense source of noise on the same frequency
The heat emitted by the sun is an intense source of thermal noise radiated at the same frequency range communication satellites use: radio frequencies (RF), and the receive antenna noise temperature rises significantly. A solar interference occurs because the earth station cannot distinguish between the energy from the sun and its intended communication signal. This can be expressed as a reduced Carrier-to-Interference (C/I) ratio, a degraded Carrier-to-Noise (C/N) ratio or as an increased antenna noise temperature (and thus educed receive antenna G/T) as the Interference (Noise) increases during the sun transit.
Solar Interference is a once-a-day phenomenon
For the receive earth station, this once-a-day natural phenomenon of additional solar thermal noise is noticed as a source of interference, which causes signal degradation (interference causing lower link availability) or even daily outages (total signal loss) for small periods of time. The timing and duration of the interference, as well as level of service degradation, varies based on the receive earth station location, its size and operational frequency. For earth stations located in the northern hemisphere, this interference occurs for several days just prior to the spring equinox. It also occurs just after the autumnal equinox (exactly reversed for the southern hemisphere). In general, sun interference occurs during the morning hours for earth stations situated at longitudes west of the sub-satellite point. Sun interference occurs during the afternoon for those earth stations that are located east of the satellite’s orbital location.
If you have questions or concerns about your cable service, please contact our support center for help and additional information.
