Iridium spectral coverage calendar
The calendar shows the 'is' files received from all iridium stations active for the entirety of the given month. On each day of the calendar, a horizontal row is drawn for each station. The left-hand end of the row is the 00 UTC hour, the right-hand end is the 23 UTC hour; gaps are show for any half hour when the station didn't receive an is file. Thus vertical white lines on the plot represent iridium system outages, when no stations received data.