The following rules apply to all solar outages:
The dates listed on nprds.org are those for which the solar disk will be within the beam pattern of your receive antenna and are given for the center of the state in most cases. On these days you will see a definite reduction in performance as the sun passes. All stations will see a reduction of Eb/No readings 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.
The dates and times listed are for the peak of the interference. Depending on the size of your antenna, the interference may begin up to four minutes before this time and last up to four minutes after it. The interference will be longer on days in the center of the range. There will also be dates, both before and after peak interference predictions, where you will experience noticeable reduction of Eb/No readings.
The times are given in NPR network time, which is Eastern Time.
These predictions are based on a 365-day year. The variations from year to year are so small that separate predictions for each year are not necessary.