The founder of the maidenhead locator system, a British radio amateur Dr. John Morris, which later became adopted by a group of VHF (very high frequency) managers at a meeting that took place in Maidenhead in 1980.A more common name for the maidenhead locator system and probably more recognisable is grid square.

A grid square measures 1 degree latitude by 2 degrees longitude and measures approximately 70 x 100 miles in the continental US. A grid square is indicated by two letters (the field) and two numbers (the square). 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 cover 10 degrees of latitude by 20 degrees of longitude and are called fields. 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, this gets us the EL29 which is what most people will exchange.

There are a few places in which to start to look if you are interested in finding your longitude and latitude;

-Lookup your Lat/Long online satsig. Enter your postcode or zip code before clicking on the "Send" button. Then click on the plus sign to further narrow down your search location.

-Use a topographic (or topo) map. These maps contain both elevation data, by means of contour lines, and location via coordinate systems. Topo maps of UK areas are available from internet search engines. The most useful series of maps for finding latitude and longitude are the 7.5-minute maps, each of which covers an area of 7.5 minutes of longitude by 7.5 minutes of latitude. Most of these are at a scale of 1:24,000 (1 inch = 24,000 inches, or 2,000 feet).

If you are interested in further information on amateur radio techniques or wish to attend any events then check out the RSGB (radio society of Great Britain) website. Hopefully this article has briefly outlined what the Maidenhead locator system is and how it is used so next time your looking at a map try it for yourself Or next time you are on the M4 out of London, you could visit the Maidenhead the place that lends its name to this system.