When you have finished looking at the maps, press an appropriate button to go to a different section.
If there are no buttons on the left, you probably got directly to this page via a search engine. Select normal access to go to the G3NPF/M1AIM home page.
There are three main systems used in radio communications to define a given area of the earth's surface. Two are used primarily by the Amateur Radio Service, while the other covers all Radio Communication Services. Unfortunately, there is no real compatibility between these systems. A fourth system, peculiar to the UK, relates to the "Worked All Britain" award. As its name implies, this is only relevant to the UK, and "WAB Squares" are the 10km squares of the National Grid Reference system denoted by a four character group consisting of the two letters denoting the 100km squares followed by two figures denoting the 10km squares, e.g. TQ11 for the home QTH of G3NPF/M1AIM.
The "Maidenhead QTH Locator System" is the official QTH locator system adopted by the IARU (International Amateur Radio Union) and replaces the old "QRA Locator System". The new system is used primarily by the Amateur Radio Service and uniquely defines any given point on the surface of the globe to within an area of 5 minutes of longitude by 2.5 minutes of latitude. This is achieved using a six character reference, although this can be extended to eight characters, with a corresponding increase in resolution. Normally, only the first six characters are used and a graphic explanation of their derivation is given below. Some GPS (Global Positioning System) receivers can be programmed to display Maidenhead QTH Locators directly. The main disadvantage of the old QRA Locator System was that several points on the earth's surface had the same reference. When first introduced, this did not present a problem, but as the equipment and operating techniques improved, so did the ranges achieved, which gave rise to possible ambiguities.
The QTH Locator System is primarily used on the VHF bands, the six character groups forming part of contest exchanges and it is also often used during normal QSOs to pin-point a station's location. Also, its use is mandatory on the 5MHz (60m) band, where it is used to compute data collected during the current propagation experiment. There is also considerable interest in "collecting squares" (defined by the first four characters of the QTH locator, e.g. IO90). A map showing G3NPF's current tally of squares and countries worked on 50MHz is regularly updated and posted on this web-site.
As an example, the home QTH of G3NPF and M1AIM has the QTH Locator reference of IO90TW. The first two characters (IO) define the major field as shown on the first map below. The derivation of the remaining four characters is shown on the second diagram. The third map is a more detailed view of the British Isles showing the relevant squares and the location of IO90TW. The old QRA Locator reference for the G3NPF/M1AIM home QTH was ZK08F.
There are many computer programs for calculating locators available, including one written many years ago by G3NPF, which may be downloaded from this web-site. Calculations made from latitude and longitude values or National Grid References will be accurate, but conversions from locators or WAB squares relate to the centres of the squares and could, therefore, be subject to small errors depending upon the precise position of a given point within the square.
As can be seen, most of the British Isles lie in the "IO" field but parts of the South East and East Anglia (those areas located to the East of 0 degrees longitude) are in the "JO" field, the Shetland Islands are in the "IP" field, while the Scilly Isles and the Channel Islands are in the "IN" field.
The fourth map shows the zoning system devised by CQ Magazine and is only used by the Amateur Radio Service. These zone numbers are used during HF band contests organised by CQ Magazine, where they form part of the contest exchange.
The fifth map shows the internationally agreed zoning system devised by the ITU (International Telecommunications Union, which is an Agency of the United Nations) and is used by all radio broadcasting and communication Services, including the Amateur Radio Service. These zone numbers are used during many international HF Band contests, where they form part of the contest exchange.
Go to:- Top of page QTH Locator Fields Detailed map of the UK QTH Locator squares CQ Zone map ITU Zone map
Go to:- Top of page QTH Locator squares and sub-squares information Detailed map of the UK QTH Locator squares CQ Zone map ITU Zone map
Go to:- Top of page QTH Locator Fields QTH Locator squares and sub-squares information CQ Zone map ITU Zone map
Go to:- Top of page QTH Locator Fields QTH Locator squares and sub-squares information Detailed map of the UK QTH Locator squares ITU Zone map
Go to:- Top of page QTH Locator Fields Detailed map of the UK QTH Locator squares QTH Locator squares and sub-squares information CQ Zone map
When you have finished looking at the maps, press an appropriate button to go
to a different section.
If there are no buttons on the left, you probably got directly to this page via a search engine. Select normal access to go to the G3NPF/M1AIM home page.
