Every amateur radio or ham radio station has a call sign. The reason for ham radio stations being given callsigns is that it is necessary to identify each station around the globe. With world wide radio communications possible, ham radio stations can be heard from many hundreds of different countries. In fact it was quickly found after radio started to be used that there was a need to organise radio communications. Part of their efforts to achieve this included assigning a call sign (callsign) to every radio station including amateur radio stations.
Even today many radio stations use call signs, and this forms an essential part of the communications protocol. Obviously it is not necessary for applications such as cellular phones, or wi-fi use call signs as such, but even these forms of communication use various identifiers. If they did not, then it would not be possible to route the data and telephone conversations to the correct destination. However the maritime and aeronautical services use call sign along with ham radio operators and this enables the station to be uniquely identified.
Ham radio call sign structure
All callsigns have an internationally agreed structure, and in this way it enables not only the station to be identified, but it also gives an indication of the country in which the radio station is located. Call signs for the maritime, aeronautical and fixed radio services along with those used for ham radio operation have a slightly different format, but despite this it is possible to identify what sort of station is being heard by its call sign and its country of origin.
A ham radio call sign consists of two elements:
- Callsign serial characters
As the name suggests, the prefix is the first part of the call. It consists of up to three characters and it is that part of the call up to and including the last number. In other words in the ham radio call sign G3YWX, the prefix is G3. For VP8ANT it is VP8, and for 2E9QQQ it is 2E9.
The remainder of the call sign may consist one to three letters. These are effectively the "serial number" of the call. These days most ham radio call signs have three letter, although in countries where there are very few stations, one or two letters may be used. Also very old amateur radio callsigns may only have one or two letters.
Countries, prefixes & call signs
Each country is allocated prefixes for the radio call signs which it can use, and by reference to a list it is possible to identify the country and sometimes a district within the country where the station is located.
An example of a typical ham radio call sign is G3YWX. In this ham radio call sign, the prefix is G3 and from the list of amateur prefixes it can be seen that the station is located in England. Similarly the station VP8ANT is either in the Falkland Islands, South Georgia, South Shetland Islands, South Sandwich Islands, South Orkney Islands or the Antarctic. In fact this particular station was located in the Antarctic.
During contests or when stations are on the air from special events, stations may use different prefixes in their callsigns so that they can attract more attention. Whilst these prefixes may not be within the normal amateur radio callsign lists they still fall within the internationally agreed prefixes allocated to countries for all types of stations.
QSL card showing the contest ham radio callsign ZP50Y
The normal callsign for the station is ZP5JCY
Call sign area codes
Sometimes the authorities within a country that issue ham radio callsigns further subdivide the callsign blocks they are able to issue so that it is possible to determine the actual area within the country where the amateur radio station is located or where the callsign was issued. A prime example of this is the USA where the last numeral in the prefix for stations on mainland North America indicates the state in which the call sign was issued. Canada also adopts a similar approach with their call signs, along with many other countries.
QSL card showing the callsign ZA1A (Albania)
Ham radio call sign suffixes
Often suffixes are added to a ham radio call sign. When a station is operating from an automobile it will use the suffix /M for mobile. The suffix /P may be used for portable operation, and /MM for maritime mobile. Occasionally /AM will be heard when a station is aeronautical mobile.
With international travel more common these days radio amateurs often want to set up stations in other countries. If they anticipate being there for some while a totally new call sign for the country in question is usually allocated. However if a short stay is envisaged the station is often not given a new call sign. Instead the home callsign is used with the prefix of the country where the station is located. Traditionally this additional prefix was added after the main call sign. For example G3YWX/VP9 would be located in Bermuda. However new international regulations suggest that and additional prefix is placed before the call sign. In this way F/G3YWX would be located in France.