In accordance with Ofcom's Amateur Radio Licence Terms, Conditions and Limitations Section 2:
Clause 13(1): The Licensee, or, if this Licence is a Full Licence, then any other authorised person who uses the Radio Equipment, shall ensure that:
(a) the station is clearly identifiable at all times;
(b) the Callsign is transmitted as frequently as is practicable during transmissions, unless the specific requirements of Note (g) to the Notes to Schedule 1 of this Licence apply; and
(c) the Callsign is given in voice or other appropriate format consistent with the mode of operation.
This means I must ensure that when when on air other people must be able to uniquely identify me, at all times.
Though it is not specific, I must give my call sign as frequent as possible. Good Practice means I should give it:
(a) When making an initial or CQ Call.
(b) When changing frequency (give it on the new frequency).
(c) On each substantive 'over'
There are specific rules regarding 5Mhz (60m Band), which in accordance with Ofcom's Amateur Radio Licence Terms, Conditions and Limitations Section 2, Schedule 1 Note (g) Subsection (vii):
Schedule 1 Note (g) Subsection (vii): Where the Licensee intends to operate within a “net” (a network), the Licensee shall observe the following requirements in relation to the transmission of his or her Callsign:
(a) The Licensee shall transmit the station Callsign when he first joins the net and on leaving it;
(b) subject to sub-clause (c) below, whilst participating in the net, the Licensee shall not be required to transmit the station Callsign when making contact with other participants;
(c) where the Licensee’s transmissions have been other than in speech mode for at least fifteen minutes, the Licensee shall transmit his call sign when next he transmits speech.
This means when operating on 5Mhz, which is only permitted by full licence holders, requires:
(a) I MUST give my callsign when joining or leaving any net.
(b) I MUST give my callsign at least every 15 minutes in the same mode as I am operating on.
(c) MUST if operating at a Temporary Location within the UK, the Licensee shall give the location of the Station every 30 minutes to an accuracy of at least 5km by a generally used identifier as indicated in Note (e) to the “Notes to the licence” (i.e. give a post code, Maidenhead Locator or NGR).
In accordance with Ofcom's Amateur Radio Licence Terms, Conditions and Limitations Section 2:
Clause 2(2): The Licensee shall use the following appropriate Regional Secondary Locator after the United Kingdom Callsign prefix “G”, “M” or “2” as specified in Section 1, when identifying the Radio Equipment in accordance with Clause 13(1):
(a) England - No Regional Secondary Locator;
(b) Guernsey - “U”;
(c) Isle of Man - “D”;
(d) Jersey - “J”;
(e) Northern Ireland - “I”;
(f) Scotland - “M”;
(g) Wales - “W”
Clause 2(3): If the Callsign specified in Section 1 begins with the number “2”, the provisions of Clause 2(2) shall apply
with the addition that when used in England, the Secondary Locator “E” shall be used.
This means the operator MUST assign the correct RSL in the callsign depending on where they are in the, and must remember that when driving the RSL may change if they cross a regional border (i.e. driving between Wales and Scotland the call may start as GW1CQP/M, become G1CQP/M and then change to GM1CQP/M during the same journey).
If operating as a full licence in Marine Mobile mode ("/MM") if in territorial waters I must use the relevant RSL, however, once outside of territory waters I must not use any RSL (i.e. I set sail from North Wales over the top of Northern Ireland to go to Iceland, I will start as GW1CQP/MM, become GI1CQP/MM, then become G1CQP/MM arriving in Iceland as TF/G1CQP/MM).
In accordance with the Note (d) of Ofcom's Amateur Radio Licence Terms, Conditions and Limitations:
Note (d): When operating at locations other than the Main Station Address, it is recommended that the following suffixes be used:
I. If the Licensee operates the Radio Equipment at an Alternative Address, the Licensee may use the suffix “/A” with the
Callsign;
II. If the Licensee operates the Radio Equipment at a Temporary Location, the Licensee may use the suffix “/P” with the
Callsign;
III. If the Licensee operates the Radio Equipment from a Mobile location, the Licensee may use the suffix “/M” with the
Callsign;
IV. If the Licensee operates the Radio Equipment from a Maritime Mobile location*, the Licensee may use the suffix “/MM”
with the Callsign.
If I am operating from the main address (the home address) I do not need to use a suffix i.e. G1CQP.
If I am operating from a different address, but one that has a postcode, I should add the /A i.e. G1CQP/A.
If I am operating from a location and have the antenna in contact with the ground, I should add /T i.e.G1CQP/T
If I am operating on foot, in my car, on vessel in inland waters landward of low water, I should add /M i.e. G1CQP/M
If I am operating on a vessel/boat/ship* seaward of low water, then I should add the suffix /MM i.e. G1CQP/MM
* Only full licence holders my operate Marine Mobile
Note that UK bands such as 50 & 70MHz (60m and 4m Band) are not allocated in the ITU Regulations and therefore would not be permitted for /MM operations.
The International Telecommunication Union (ITU) allocates call sign prefixes for radio and television stations of all types. They also form the basis for, but may not exactly match, aircraft registration identifiers. These prefixes are agreed upon internationally, and are a form of country code. A call sign can be any number of letters and numerals but each country must only use call signs that begin with the characters allocated for use in that country.
The UK prefixes both current and historic are:
Current:
Foundation M7 + 3 letters 2018 -
Intermediate 2*0 + 3 letters 2001 - (Note MUST also RSL)
Full M0 + 3 letters 2001 -
Past:
Foundation Licence
M3 + 3 letters 2002 - 2008
M6 + 3 letters 2008 - 2018
Intermediate
2E1 + 3 letters 1991 - 2001 (Now available by special request to OfCOM)
Full
G0 + 3 letters 1986 - 1996. Originally issued as a Class A licence
G1 + 3 letters 1983 - 1988 - Originally issued as Class B licence
G2 + 2 letters 1920 - 1939 - Originally issued as a Radiating Licence (pre WW2)
G2 + 3 letters 1920 - 1939. Originally issued as "Artificial Aerial" licence (pre WW2)
G3 + 2 letters 1937 - 1938 - Originally issued as a Radiating Licence (pre WW2)
G3 + 3 letters 1946 - 1971. Originally issued to all amateur radio licence holders and after 1964 Class A amateur radio licence holders
G4 + 2 letters 1938 - 1939 - Originally issued as a Radiating Licence (pre WW2)
G4 + 3 letters Issued between 1971 and 1985. Originally issued to amateur radio class A licence holders.
G5 + 2 letters 1921 - 1939 - Originally issued as a Radiating Licence (pre WW2)
G5 + 3 letters 1966 - 1981 Originally issued to foreign nationals as a form of reciprocal ham radio licence.
G6 + 2 letters 1921 - 1939 - Originally issued as a Radiating Licence (pre WW2)
G6 + 3 letters 1981 - 1983. Originally issued as a class B licence
G7 + 3 letters 1989 - 1996. Originally issued as a class B licence
G8 + 2 letters 1936 - 1937 - Originally issued as a Radiating Licence (pre WW2)
G8 + 3 letters 1964 - 1981. Originally issued as a class B licence
G0 + 3 letters 1986 - 1996. Originally issued as a class A licence
M1 + 3 letters 1996 - 2003. Originally issued as a class B licence.
M5 + 2 letters 1991 - 1996. Originally issued as a class A licence
M5 + 3 letters 1996 - 2001.
* In the very early days of Amateur Radio (just after the 1914-18 war) the British amateurs were distinguished by the initial
figure "2". The "2" was doubtless allotted because there was, and still is, a horror in some circles of using "O" or "l", which might be mistaken in writing for the letters "O" and "I". So all British amateurs were "2's".
Prior to 1923, there was no enforced Country prefix added to call signs, however, the letter 'G' was assigned to Great Britain and amateurs were encouraged to use it when communicating internationally. This was formally adopted as part of the call sign after WW2.
GB/MB call signs
The GB or MB prefix is used for a variety of special ham radio licences ranging from repeaters and beacons to data mailboxes and special even stations. It is possible to tell the use of the station and licence from the format of the callsign.
GB3 + 2 letters - Repeaters
GB7 + 2 letters - Repeaters
MB7 + 2 letters - Repeaters
GB3 + 3 letters - Beacons
GB7 + 3 letters - AX25 /Packet
MB7 + 3 letters - AX25 /Packet
GB + other digits not mentioned above - Special event stations (i.e. GB100RAF or GB1NHS)
Last Updated 10 April 2022.