Everything you need to know about grid squares

Collecting "grid squares" is a popular pursuit on VHF and UHF bands, but what exactly is a "grid square", and how do I determine mine?
Background

Back in the 1950's, a need amongst European VHF/UHF amateurs was recognised to abbreviate the way in which location information was specified. A system using two letters to identify a "square" that was 2° (longitude) by 1° (latitude) was devised, but only provided limited coverage over Europe.

This system became very popular, and in 1979 new systems were proposed that would offer worldwide coverage. In April 1980 a meeting of VHF managers was held at Maidenhead (near London) to determine the best system that should be implemented.

What we now know as the Maidenhead Locator System, where the world is divided into 32,400 subsquares, was adopteded by all three IARU regions by 1984.
Maidenhead Locator System - Fields, Squares and Subsquares

The earth's surface is divided into an 18 x 18 grid, totalling 324 "fields".

Fields encompassing VK/ZL can be seen in Figure 1.

These big field "squares" are 20° in longitude x 10° in latitude.
Note these fields, and the smaller subdivisions within them are actually rectangular.

Fields are represented by two letters and range from AA - RR.

The first character represents longitude, and the second character represents latitude.

Canberra, Sydney and Melbourne are all within the QF field. Brisbane in QG, Adelaide in PF, and Perth within OF. The Apple Isle is in QE, whilst Darwin is in PH.

Most of the New Zealand North Island is in RF, whilst the South Island is in RE.

Figure 1 - the Maidenhead fields covering our region

Every field is then further divided down into a 10 x 10 grid.

Each of these 100 middle sized squares are 2° in longitude x 1° in latitude.

Squares are represented with two digits and range from 00 - 99.

Again, the first character represents longitude, and the second character represents latitude.

Refer to Figure 2 and you will see the horizontal and vertical pattern in numbering.

This level of locator detail is what people generally mean when referring to grid squares.
Figure 2 - this is field QF, note the 10 x 10 = 100 squares within

Every square is then further subdivided down into a 24 x 24 grid containing smaller subsquares.

Each one of these 576 subsquares are 5 minutes in longitude x 2.5 minutes in latitude.

Subsquares are represented by two letters and range from AA - XX. Often, but not always, these letters are in lowercase.

Yet again, the first character represents longitude, and the second character represents latitude.
See a pattern here?

Subsquare example using Figure 3:

Latitude = S37° 26.1'
Longitude = E144° 33.8'

Grid Locator would = QF22gn
Figure 3 - a close look at the QF22 square. Subsquares AA - XX    
The essential Bible!

The ARRL World Grid Locator Atlas is an excellent 24 page reference booklet that all shacks should have!

Written by Folke Rosvall, SM5AGM, co-founder of the Maidenhead locator system, it explains the Maidenhead system and provides methods of calculating a grid square.

There are 18 maps of the world showing all 32,400 grid squares. This booklet provides a fun way of highlighting squares as you work them.

It used to be commonly available from DSE and many other (now defunct) VK ham radio stores. Don't give up, as there may be old stock lying around. Ring around and try your luck with the surviving amateur radio stores.

Failing that, it is available from the ARRL online catalogue for USD$5 + post, and can be mailed directly to you.

My copy purchased in 1992 was AUD$10 from Stewart Electronics, so the ARRL price appears reasonable.
How to determine my own grid square?

Modern method to detemine grid square (and latitude/longitude)

Nowadays, you don't need to 'calculate' anything, as such, and it's very easy.

By using VK Logger's Mapping facility (based on Google Maps), you can easily determine a full 6-character gid square anywhere on the planet!

Navigate to your location, and left click on the spot.

It takes the average user less than 90 seconds to find their grid square, and/or latitude/longitude.

Traditional methods to determine grid square

Your Lat/Long can be obtained off most 1:10,000 "Topo" maps produced by the various mapping companies.

Take a visit to your local library and check out the Topo map that covers your area. Make a note of your Lat/Long. You can use a ruler to measure the distance between map grid lines to determine a Lat and Long to a reasonably high precision.

Understanding the principles above, and using some basic maths, it is a relatively easy to calculate your 6-character grid locator square.

Enter the Lat/Long into the online calculator, or use one of the many programmes downloadable from the internet, to determine your grid square.

These days many GPS receiver have the capability to display the co-ordinates directly in Maidenhead format.

If you don't own a GPS, then post your query to the VK Logger Discussion Forum, or the VK-VHF mailing list. Somebody is sure to reply with your subsquare.

If you live in metro Melbourne, Sydney, or Brisbane, then you can use an Ausway street directory!

The Melways, Sydways and Brisways street directories use the AMG (Australian Mapping Grid) and virtually all GPS receivers have the ability to display/compute using UTM. UTM is the same as AMG.

These AMG lines can be seen on every map, and again, using a ruler you can determine your AMG reference to better than 100m. Using a GPS, even an older unit without Maidenhead, you can convert AMG co-ords to , Degrees/Minutes/Seconds, or decimal Degrees, and then plug these figures into the calculator software.

For contesting purposes, it's not essential to know your full 6-character Maidenhead Locator Square, as most activity only requires knowing your 4-character square... but it's nice to know, and others might quote theirs anyway!
VHF/UHF Logging Software

There are many logging packages available for your PC, but most are HF and/or contesting orientated, and few support the entry and data reporting of gridsquare data.

One excellent VHF/UHF orientated logging package is VQ Log.

Written by EA6VQ, it is used by many ardent VHF DXers around the world because the author has built in many features that a VHF/UHF operator requires.

Free to download and use, and should you decide to pay the modest registration fee (only USD$18), you will receive free upgrades and tech support.

Definately worth a look.
Gridsquares Map to colour in

Below is a map of our region, and it prints out quite well on a mono laser, and conveniently fits on A4 paper, when printed in Landscape mode.

The individual squares can be coloured in with a highlighter pen, and can provide a quick visual guide as to what you have worked.

You could print a map for each band you operate, and/or use different highlighter colours.
To save this image on your local harddisk, right-click on the image above select Save Image As...
Awards

For "wallpaper chasers", the WIA offer a "Grid Squares Award" and the ARRL offers it's VHF/UHF Century Club Award.

 

Adam Maurer, VK4CP
24 October, 2005