When you hear someone asking "What's your grid square" or if you hear someone yelling "DOØØ" are they asking or telling you a location? You bet! Think of it - do you really want to tell someone you are at "48º 51' 32" North and 002º 17' 45" East or would you rather be in JN18du*?
Maidenhead grid squares divide the globe into 324 large areas of 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. The two letters that follow a grid square further define your location within that square by dividing each square into a sub-square. These sub-squares are 5 minutes by 2.5 minutes.
You can use this handy tool to look up your stations gridsquare, or the gridsquare of that rare DX station you just worked. You can enter your location in decimal degrees or degrees, minutes, second!
*Location of the Eiffel Tower
If you don't know your station's Latitude and.or Longitude, you can look it up on QRZ or Hamcall: