What is Maidenhead Grid Locator System in Ham Radio?

What is Maidenhead Grid Locator System in Ham Radio?

Earlier location of station in the Q code QTH used by amateur radio operators was mentioned in latitude and longitude. Now it is mentioned using the Maidenhead Grid Locator System. It is also called as QTH Locator and IARU Locator. Various online resources are available to get your grid location if you know the latitude and longitude and vice versa.

Distance between grids can also be found using these calculators. Recommended short form for use in Morse Code is LOC. The grid locator system was originally devised by G4ANB and adopted by a meeting of the International Amateur Radio Union held at Maidenhead in 1980. Maidenhead is a town is situated 43 km west of Charing Cross, London.

Grid squares are a simple method of describing your general location anywhere on Earth. One grid square measures one degree latitude by two degrees longitude. Total number of grid squares on the globe would be 32,400. Measurement of the grid square in Kilometers or Miles would vary depending on the region and will become smaller as you approach the poles. Grid AA is located in Antartica. Hundred grid squares are grouped into a grid field.

Grid field is indicated by two letters and grid square will have two numbers in addition to the letters indicating the field. Grid fields are named using two letters from A through R. The globe is thus divided into 18 zones of longitudes of 20 degrees each, and 18 zones of latitude 10 degrees each. Total grid fields would be 18 x 18 = 324 and the grid squares 324 x 100 = 32,400. Grid squares have two digit designations using digits 0 through 9. My grid location will be mentioned as MK71.

Grid squares are further divided into subsquares, encoded by a second pair of letters usually mentioned in lower case. Each subsquare has a dimension of 2.5′ of latitude and 5′ of longitude. Letters ‘a’ through ‘x’ are used for mentioning subsquares. My location would be specified as MK71vg.

Additional two more digits could be added as extended locator which divides subsquares into divisions of 15″ of latitude and 30″ of longitude. This would make a total of eight characters. But I have not seen this being routinely used on the band or in articles mentioning grid square locations online.

Grid squares are commonly used by satellite rovers who operate through satellites using portable amateur radios from a location other than their home location. There is an AMSAT Rover Award awaiting active Satellite Rovers. VHF/UHF contests use Maidenhead locators as part of formulas for scoring while determining awards.