Grid Locator System
ABC of Grid Locator System
N. S. Harisankar / VU3NSH
Tel : +91 491 2576102, 9895741932
The Grid Locator System or the Maidenhead Locator System is a geographical co-ordinate system and it is the non-square shape on any non-equi-rectangular catographic projection. This system is devised by Dr. John Morris G4ANB. The description of the system is based on 6 digit or 8 digit data and it contains longitude, latitude, square, sub-square and extended square etc.
This is the easy way for a amateur radio operator (HAM) to locate other stations, countries, regions, cities and their home towns, where the signals are coming from. For Example, the grid MK80ht (6 digit data) is my QTH (my residing area). It is thedivisions of three groups of data MK, 80 and ht.
The world is divided into 324 fields by dividing the globe into 18 zones of longitude of 20° each, and 18 zones of latitude of 10° each. These Zones of Longitude marks are represented by A to R and the zones of latitude also with these same letters. In MK80ht, the crossing area of longitude zone M and latitude zone K is the field MK. The first pair of alphabets MK represents 60° to 80° East Longitude and it isMand 10° to 20° North Latitude is K. The figure 1 shows the total field of MK.
Then, one field is divided into 100 squares and these squares are represented as the second group of data starting from 00 to 99. Here (MK80ht), the particular square is represented as 80 (See figure 2) and each squares are divided by 1° of Latitude and 2° of longitude (See figure 3a and 3b also).
The 3rd pair of alphabets "ht", is called a sub square and it is divided by 2.5 minutes
of latitude and 5 minutes of longitude approximately (See figures 4, 5, 6 and 7).
Figure. 1. Field MK from Globe
Figure. 2. Divisions of MK Field
Figure. 3a. Square 80 from MK Field
Figure. 3b. Areas coming under Square MK80
Figure. 4. Sub Square from Square ht 80. Four boundaries of MK80 and my QTH MK80ht
Figure. 5. Method of Sub Square divisions by alphabets from a to x
Figure. 6. Detailed view of My Grid Square MK80ht
Figure. 7. Divisions of Field, Square and Subsquare
Extended Subsqure Divisions
Figure. 8. Extended Subsqure Divisions of MK80ht
Figure. 9. Extended Subsqure Divisions of MK80ht
I hope this simple explanation may help you to understand about the Grid Locator System and to find out any location in the world. This article is dedicated to my master C. P. Nithyanandan, EME Rtd. I thank VU2DX, VU2VKC, VU3EMX for the help and support for the preparation of this article. My special thanks to SWL Rejeesh.K.R. for the graphic designs.
 Mapper v4.0 Screen Shots (Ham Radio Deluxe Software by HB9DRV)