ARRL

Grid Squares

Introduction

One of the first things you will notice when you tune the low end of any VHF band is that most QSOs include an exchange of "grid squares." What are grid squares? Well, they're more like rectangles and are just a way of dividing up the surface of the Earth. Grid squares are a shorthand means of describing your general location anywhere on the Earth in a manner that is easy to communicate over the air.

An instrument of the Maidenhead Locator System (named after the town outside London where it was first conceived by a meeting of European VHF managers in 1980), a grid square measures 1° latitude by 2° longitude and measures approximately 70 × 100 miles in the continental US. A grid square is indicated by two letters (the field) and two numbers (the square), as in FN31, the grid square within which W1AW, ARRL's Maxim Memorial Station, resides.

Each subsquare is designated by the addition of two letters after the grid square, as FN44ig. These more precise locators are used as part of the exchange in the 10-GHz contest. They measure 2.5 minutes latitude by 5 minutes longitude, roughly corresponding to 3 × 4 miles in the continental US.

Articles

Conversion Between Geodetic and Grid Locator Systems  Members Only
QST
Jan 1989, pp. 29-30, 43 This simple paper system lets you convert latitudes and longitudes to grid locators.

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