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Sun outages occur when a satellite, usually one in a geostationary orbit, passes between a ground station and the sun. Seen from the point of view of the ground station, the sun looks like it passes behind, or at least close to the satellite. When this happens the weak radio signal received from the satellite is overwhelmed by the loud radio noise generated by the sun, and the link is broken for a short period each day for the period of a week or so, twice a year.

I have noticed that sun outages for commercial broadcast are not impacting as often or as severely as for other satellite dishes (telecom dishes for example). Most of the time, there seems to be almost no impact on viewing.

I am wondering if perhaps this might be due to the fact that TV carriers are more powerful and somehow avoid sun interferences? Or maybe it is related to the design of direct television RX antennas?

Thanks for any insight you could share.

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  • $\begingroup$ David can you clean up your question? What do you mean by "sun outages"? And what does this have to do with space exploration? Also I'm just not sure what you're asking in general. $\endgroup$ – Arthur Dent May 31 '17 at 19:42
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    $\begingroup$ Someone here may still be able to answer it, but again I don't know what the question is. I'm guessing English isn't your native language, but if you could phrase it in another way someone might understand. Are you asking why solar eclipses don't affect TV antennas? $\endgroup$ – Arthur Dent May 31 '17 at 20:17
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    $\begingroup$ @davidmarchioni take a look to see if I have interpreted your question correctly. Questions are better received if they contain links to special terms, so I have added the link to sun outage. These links may be helpful to someone writing an answer 1, 2, 3, 4 $\endgroup$ – uhoh Jun 1 '17 at 1:07
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    $\begingroup$ Hi all many thanks for your assistance. No, it is not related to my other question. let me ask another way (english ios not my native langage ;)) it seems that TV dishes (offset parabols) are less affected by sun outage than telecom antenans (Cassegrain) ? do you confirm, and if yes, why ? $\endgroup$ – david marchioni Jun 1 '17 at 6:54
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    $\begingroup$ TIL sun outages are a thing. $\endgroup$ – Arthur Dent Jun 1 '17 at 15:04
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The sun outages (also called solar interference) you are describing only occur for a few times a year for each geostationary satellite and are very short. They most certainly affect satellite TV carriers.

From a carriers website it seems there is potential for outages for 15 minutes a day for 6 days.

The effects are seen on most channels and occur during various times of the day, lasting up to 15 minutes. You may experience short service interruptions between Friday, March 3, 2017 and Wednesday, March 8, 2017

This site describes how the outages are caused.

The degree of interference caused by a satellite solar outage varies from slight signal degradation to complete loss of signal as the downlink is swamped by the noise from the Sun.

The duration of the sun outage depends on several things: the beam width of the field of view of the receiving ground antenna, the apparent radius of the Sun as seen from the Earth (about 0.25°), the RF energy given off by the Sun, the transmitter power of the satellite, the gain and S/N performance of the ground station receive equipment, and other factors. All of this can be used to determine the outage angle of the receive antenna. The outage angle is defined as the separation angle (measured from the ground station antenna) between the satellite and the Sun at the time when sun outage or signal degradation begins or ends (see diagram).

Differences in outaged between services and carriers can often be related to which satellite is being used. for example a satellite tv installation might be using geostationary satellites in orbital positions 110, 119, and 129 degrees. Only the services on a satellite that you are actually using, and that passes very close to the sun from your point of view will be affected.

Sites such as this can be used to predict outages for particular services and to see how using a different satellite changes the results.

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  • $\begingroup$ thanks i know what is a soular outage. seems my question was not clear enough...not a big issue. thanks $\endgroup$ – david marchioni Jun 2 '17 at 12:22
  • $\begingroup$ I've reread the question and see how i may not have fully answered it. I think i would need more information about which telcom satellites are being compared to which tv satellites to answer properly. When it comes down to it i suspect the answer is more a question of position that transmitter power. A tv broadcast satellite only uses only about 125W per transponder. Consider trying to see a 125W lightbulb at 36000km when the sun is behind it. The sun pretty effectively drowns all other EM signals in this case. $\endgroup$ – OrangePeel52 Jun 2 '17 at 13:11
  • $\begingroup$ another way to ask :) : with cassegrain antennas (such as 4.6 meters and more (i.ytimg.com/vi/kesOxcLo1tk/maxresdefault.jpg) carriers are affected by sunoutage. With satelltie tv antennas (media.ldlc.com/ld3/zoom/2011/LD0000853534.jpg), i did not noticed any sun outage issues... in case it is not clear, do not worry, close the issue...:) $\endgroup$ – david marchioni Jun 6 '17 at 7:05
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Many commercial uplinks will dual illuminate. Meaning that they will put up another signal on a different satellite that can be used while the other one is dealing with Solar Interference. Once the sun moves past the main satellite, then reception can be switched back to it and the 2nd feed removed.

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  • $\begingroup$ This is interesting! If you can add a link or reference to that so people can read further, that would be great. Thanks! $\endgroup$ – uhoh Mar 5 '18 at 2:57

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