The map is divided into Maidenhead Locator Squares which are numbered when the MUF (Maximum Useable Frequency) is not displayed within it. “Large Square” locator letters are also displayed on the map (“IO”, “JO” etc).
When propagation is present and reported, coloured rectangles indicate the MUF in those squares in MHz as calculated by the Live MUF application for contacts during the last 30 minutes.
The colouring is scaled between yellow and red (28 MHz to 200 MHz).
White parallel lines crossing the map = day/night terminator
Yellow star = Sub-solar point
The data block in the bottom left corner includes the date and the start/end times for the 30 minute period of the current map in UTC.