Help - All About Grid Squares

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Help - All About Grid Squares

Postby ADMIN » Sun May 10, 2009 11:52 pm

Collecting "gridsquares" is a popular pursuit on VHF and UHF bands.
But, what exactly is a gridsquare, 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.

Fields
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.

fields.gif

Figure 1 - the Maidenhead fields covering our region

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.


Squares
Every field is then further divided down into a 10 x 10 grid.
Each of these 100 middle sized grid 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.

squares.gif

Figure 2 - this is field QF, note the 10 x 10 = 100 squares within

This level of locator detail is what people generally mean when referring to grid squares. ie; Greater Melbourne is in QF22.


Sub-squares
Every square is then further subdivided down into a 24 x 24 grid containing smaller sub squares.
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.

subsquares.gif

Figure 3 - a close look at the QF22 square. Subsquares AA - XX

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


How to determine my own grid square - the modern way
Nowadays, you don't need to 'calculate' anything, as such, and it's very easy.

On-line method
By using VK Logger's Mapping facility (based on Google Maps), you can easily determine a 6-character gid square anywhere on the planet.
Navigate to your location, and left click on that location.
It takes the average user less than 90 seconds to determine their grid square and latitude/longitude.

Mobile Apps
Image
There are many free apps available for Android mobile phones and tablets from Google play.
Search on terms like; ham radio, amateur radio, gps, grid, etc.
Apple users may find the iOS versions on the iTunes store - you can investigate that yourselves.

An Android favorite of the authors is Hamgps.

Image

This handy app, using your mobiles device inbuilt GPS will;
  • Show your Grid Locator to 10 characters
  • Show your latitude longitude
  • Show UTC time
  • Calculate distance & bearing to another grid square or lat/lon
  • Indicate which way to point your antennas to that location
  • Show visible GPS satellites

Image

This is an ideal app to use in the field for VHF/UHF/microwave activity days.


GPS Receiver
These days many GPS receiver have the capability to display the co-ordinates directly in Maidenhead format.
Even if they don't, enter the Lat/Long into the online calculator, or use one of the many programmes downloadable from the internet, to convert the lat/lon into grid square.


How to determine my own grid square - the old fashion way

Topo maps
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.

If you don't own a GPS, then post your query to the VK Logger Discussion Forum, and somebody is sure to reply with your subsquare.

Ausway Street Directories
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.


How many characters?
For contesting purposes, it's not always essential to know your full 6-character Maidenhead Locator Square, and your 4-character square may suffice.
However, it is generally expected you should know your grid square to 6-characters.
With the increasing popularity of distance-based scoring, a minimum of 6-character grid square becomes essential so that a meaningful result can be calculated.

European VHF operators tend to be very progressive, and now often use 10 character grid squares - something the rest of the world could learn off!


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

Image

Originally 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$5.95 + post, and can be mailed directly to you.
For ARRL members, this is the hassle free way to go.


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.

Image


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.
For a quick and handy reference, you could print a map for each band you operate, and use different coloured highlighters. :wink:

grid_map.gif


To save this image on your local harddisk, right-click on the image above select Save Image As...

grid_map_right_click.gif
grid_map_right_click.gif (9.2 KiB) Viewed 412 times



Now that you know all there is to know, start chasing grid squares! :D
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