Fall Solar Outage Season 2013

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Please be advised that the fall solar outage season will begin September 28 and last through October 15. A solar or sun transit outage is an electromagnetic phenomenon wherein a station downlink is temporarily unable to receive a satellite signal due to interference from the sun as it passes behind the satellite. Solar outages occur on a predictable schedule and affect downlinks in the U.S. for about five consecutive days, for as much as six minutes a day, twice each year. There is a pull-down menu in the lower-left corner of the home page of www.prss.org that allows you to get specific dates for solar outages for your geographic location. To obtain solar outage information for your location, click on your state or territory in the pull-down menu. (The new PRSS.org site supports the latest desktop versions of Chrome, Safari and Firefox, as well Internet Explorer 9 and 10. The site will work with Internet Explorer 8, but portions of some pages may not appear or will be broken.  For the best user experience, it’s advised that you upgrade your browser to IE 9 or higher.)

The following rules apply to all solar outages:

1.) The dates listed on the solar outage chart found on www.prss.org are those for which the solar disk will be within the beam pattern of your receive antenna. On these days you will see a definite reduction in performance as the sun passes. All stations will see a reduction of EbNo reading on the digital audio channels. If a downlink has enough margin, there will be no effect on the audio. If the downlink does not have enough margin, audio may be lost for up to several minutes. Stations with marginal downlinks may see some degradation one day before or one day after the days listed.

2.) The times listed are for the peak of the interference. Depending on the size of your antenna, the interference may begin up to 4 minutes before this time and last up to 4 minutes after it. The interference will be longer on days in the center of the range.

3.) The times are given in PRSS network time, which is Eastern Time.

4.) These predictions are based on a standard 365-day year. The variations from year to year are so small that separate predictions for each year are not necessary.

We encourage stations and producers to take the following steps in preparation for solar outages in your region:

Producers: Program producers of episodes scheduled to transmit during the outage season are encouraged to make sure their content is loaded on a timely basis. Posting evergreen episodes of live programs will give stations programming options during the outages in their regions.

Stations: Stations should consider operational requirements during the predicted outage duration for their area and download file-based content as provided by program producers.

For stations that are broadcasting live stream programming from the ContentDepot, we are now able to offer alternative routing arrangements:

1.) We will be providing on-demand internet-delivered streams of ContentDepot streams 1-24. These streams will be delivered at 128 kbps stereo in the mp3 format. They will contain no cueing information. The audio will be subject to any latency delays that may exist. Stations choosing this option would need to be able to route audio from a local computer into the audio console. Windows Media Player or QuickTime can be used to play back the audio from the computer, as two examples.

2.) We have a limited number of ISDN codecs that can be used to feed streamed programs back to stations. These, too, are configured for 128 kbps stereo at mp3 and contain no cueing information. Their latency is more consistent.

Stations desiring one of these workarounds will need to contact the PRSS Help Desk to arrange for one of these methods. We will need to know the specifics of the requirement: dates, times, and which program is desired.

Users of the ISDN option should be aware that it is strictly first-come, first-served and is preemptable in the event the NOC needs an ISDN codec to restore an inbound audio stream meant for transmission to the entire network. It is the station's responsibility to dial into the assigned codec in the NOC and pay for the ISDN connect charges. The ISDN dial-in numbers will be provided when the request is made and scheduled.

Users of the streaming option will need to disconnect from that stream as soon as possible after the solar interference has passed in order to keep bandwidth usage costs to a minimum. Stations using the internet streaming system for solar outages will not be charged, but will be required to restrict their usage to only those time windows when their local service is affected. The url for the required program will be provided when the request is made.

If you have any questions or concerns about solar outages, please contact the PRSS Help Desk at 800.971.7677 or prsshelp@npr.org.

Posted: September 16, 2013