Start your data query by selecting a station's URSI code from the "DIDBase Fast Station List" to the left. The station list can be sorted by clicking on the column titles.
DIDBase will be queried and create links within year, month, and day for the selected station. To further refine your data selection select a year, month, and day by clicking on the available links.
Once a day is selected, the ionograms for that day will be available for display. You can navigate through the iongrams with the buttons at the bottom of the display.