Maidenhead Grid squares are a scheme for identifying positions on the Earth. It was devised in Maidenhead, England when an international group decided chose the system to supplant the older QRA locator system so as to be usable outside of Europe.

Maidenhead Grid squares, or simply "grid squares" represent a position on the earth based on latitude and longitude. The world is first divided into 324 large areas. These areas, called fields, cover 10 degrees of latitude by 20 degrees of longitude. Each field is divided into 100 squares. This is where the name grid squares come from. Each of these 100 squares represent 1 degree by 2 degrees. By this means, the American Radio Relay League's Maxim Memorial Station, is found in FN31. The two letters that follow a grid square further define a location within that square by sub-dividing each square. These sub-squares are 5 minutes by 2.5 minutes, though the 6 digit form is not always used though the more precise form is required in the AARL's 10 GHz contest.

Maidenhead Grid squares are used by amateur radio operators (hams) world-wide and are recognized by organizations such as the American Radio Relay League (ARRL).

Many utilities exist to convert latitude and longitude to Grid Square as this is a favorite hack for programmers who are also hams.

External links

• Maidenhead Grid Squares (http://www.amsat.org/amsat/articles/houston-net/grids.html)
• ARRLWeb: Calculate Grid Square (http://www.arrl.org/locate/grid.html)
• ARRLWeb: Grid Locators and Grid Squares (http://www.arrl.org/locate/gridinfo.html)