The systems used are: for Great Britain - the Ordnance
Survey of Great Britain “National Grid Reference” (NGR);
for Northern Ireland - the Ordnance Survey of Ireland “Irish
Grid”; and for the Channel Islands - the “Universal Transverse
Mercator Grid” (UTM). These form the basis of the main W.A.B.
The NGR, Irish and UTM grids divide the country with a grid of 100km x 100km, which W.A.B. call “Large Squares”. The NGR and UTM give these a 2 letter reference i.e. HP, SP, TQ, WV etc. whilst the Irish Grid uses a single letter C, D, G, H & J. This is shown on the map. The Large Squares are then broken down with a 10km x 10km grid; these are given a 2-digit reference. The first digit is called the “Easting” and is read from the top or bottom of the map. The second digit is called the “Northing” and is read from the side of the map.
The 10km x 10km “Small Square” is then made up with the Large Square letters and the grid numbers, e.g. C32, HY61, SP87, WV47 etc.
Although the NGR, Irish and UTM grids are derived in the same way, they do not exactly coincide. Therefore, it is not possible to change Irish or UTM grids into NGR’s. The three systems are used.
To convert a Grid Reference to a 10km square: Split however many digits you have in your Grid Reference into two parts with an equal number of digits in each half, then use the first digit of each half. This will give you the 10km square.
“SP104728” converts to “SP17”
“NT0816416287” converts to “NT01”
The 10km x 10km “Small Square” alone does not constitute the W.A.B. Square. The W.A.B. Square is the 10km small square and the Country, e.g. “SP87 England”. The Square must contain land, and the W.A.B Square is only that land or an inland waterway in the area.
Each claim Book/CD lists W.A.B. Squares in alpha-numeric order.
Care must be taken in the interpretation of areas from small-scale maps. The addresses of British Stations given in RSGB and International Call Books can be misleading. The postal address system tends to use old County names that no longer exist.
For example, there are some places in Wales that have an English postal address and vice versa. The same is true for places along the Scotland/England border. If the station does not know their W.A.B. Square, it is advisable to ask for their exact location..
NOTE: It is NOT POSSIBLE to reliably convert Postcodes, QRA or Maidenhead (IARU) locators to W.A.B. Squares, as the boundaries of each do not align exactly with W.A.B. Squares
An Island is defined as a naturally formed piece of land lying off shore from the main land and at some time is surrounded by tidal water. The Island must be named or be part of a named group on a 1:50,000 Ordnance Survey map or an official map of the Channel Islands. The construction of a man made bridge or causeway does not take away the status of an island.