Each year, satellite downlink locations in the Northern Hemisphere experience sun transit outages during a three-and-a-half week period prior to the Spring Equinox and following the Fall Equinox. This phenomenon affects all geostationary satellites, and while it cannot be prevented, we can accurately predict when sun outages will happen.
Sun transit outage, or sun fade, occurs when the sun aligns directly above a satellite in orbit and a downlink antenna. The radiation from the sun interferes with the downlink signal from the satellite. During this period, you may hear increased noise in your network audio signal, or may lose audio altogether. Sun transit outages have very little effect when the cycle begins, steadily increasing in intensity until a peak date, and then gradually decreasing in intensity before ending. The start and end dates of the sun fade cycle for your geographic location determines the severity of a sun fade event on any given day.
SES WorldSkies has created an application to help you determine the Solar Transit Outage Predictions for your area. The program shows outage dates and times for representative cities throughout the United States. If you do not see your city listed, interpolate between areas to get your sun outage times and dates. If you are west of the listed location, the outage time will be earlier. If you are south of a listed location, the date will be later. In any case, the outage is limited to a half-hour maximum window each day.
Sun outages are predictable, so it is important to be prepared. You should familiarize yourself with the affected dates and times in your area, and have alternate programming ready. Remember, sun transit affects all geostationary satellites. Outage times will vary based on location, date, and the characteristics of your downlink antenna.
If you have any questions about sun transit outage, please call our Technical Services at (914) 908-3210.