Major Locator - The Maidenhead Locator system is based on Locator Fields and a particular location is normally specified with six characters. The world is divided into 18 x 18 locator fields, each overing an area 20 degrees East - West and 10 degrees North - South. The naming of these fields begins with AA and ends with RR.Each locator field is further divided into 100 Locator Squares (actually rectangles), that each cover 1 degree North - South and 2 degrees East - West.
For accuracy down to only a few km, locator squares can be further subdivided into 24 x 24 sub-squares by adding two extra digits from AA to XX.
My locator is QF23FF. The locator field is represented by QF, the locator square by 23 and the sub-square by FF.
The Zoom Major Locator will zoom into the map with one Locator Field occupying the majority of the window. The above image is Locator Field QF.