Use of /M in a call

Seeing M/PE4WJ/P running this morning made me think about the use of /M, as in the States thats usually used for mobile operations. Thoughts? Den using it as a prefix which is clear, but my first reaction was, is he running mobile? :slight_smile:

This is an unfortunate side effect of our regulations changing from G to M, I have seen other comments about it in the past.

M/xxxxx is not xxxxx/M

The UK has been issuing amateur Mxxxxx callsigns for 21 years now. They are not new in the amateur world.

The UK has been using Mxx commercial callsigns since 1950, so they have been in use for 67years.

This is how I see it: following common sense logic (and international operating procedures), the most important information should be in the beginning. Who am I calling, where am I, who am I, further details of my station:

K9EZ de M/YO9IRF/P would read: Calling K9EZ, I am in England, my callsign is YO9IRF and I am portable.

The fact that i’m calling you is the most important (to get your attention), the fact that I’m in England is more important than my callsign, the fact that I am YO9IRF is more important than the fact that I’m portable. If I am operating from another entity, the callsign should start with that entity’s prefix, followed by my individual call. If I am portable, I can add that extra bit of information at the end, after the important identification details have already been transmitted.



/P = portable = not at my primary location
/M = mobile = in motion

Stationary car is /P, operating on holiday is /P, using another ham’s station is /P.

/M look carefully, its M/ part of the country pre-fix.
Portable and mobile are at End of the call
M/PA says to me its a Dutch ham in England

Like me being M3FEH/p go to wales i become MW3FEH/p

If full licences holder and in say Netherlands it becomes PA/M0FEH/p


Prefixes and suffixes can vary between countries, however for CEPT countries, the host country code comes first then a slash, then the home country call and afterwards a slash and (often optional) location type m=mobile p=portable etc.

This is not always the same however - for example in Australia I have seen two documents from the regulator - one which says a visitor (lets say K9EZ) indicates he is in Australia by prefixing his call with the state callcode - e.g. VK2/K9EZ but in another document from the same organisation, it says that the state code comes after the home call, so that would be K9EZ/VK2.

In the case of the UK - if visiting Scotland 22 years ago the call would be prefixed with GM/K9EZ but as Andy pointed out that changed when the MM prefix for Scotland was adopted so now one would expect to hear you as MM/K9EZ (possibly MM/K9EZ/P when portable). In England just M rather than MM, on the Isle of Man MD instead of MM etc.
HOWEVER … four days ago I worked Joachim DH5JBR who was traveling around the Scottish Islands and using the call GM/DH5JBR/P. I queried this and he told me that he had approached Ofcom (the UK regulator) as he was having problems with so many people thinking he was maritime mobile when the prefix was MM, he told me that Ofcom said they were just as happy with the GM prefix as it also indicated operation in Scotland. I’d be interested to see this in writing and may ask Joachim when he gets home as he lives only about 25 miles away from here. The code listed in the CEPT document is MM/ however the local regulator always has the last say!

So Kent, you see, it can be VERY confusing. If you consider visiting a country, its certainly worth double checking how you should identify yourself (presuming you are allowed to operate in the foreign country either under a CEPT agreement or with a temporary license).


That’s kind of what i was thinking. I have traveled the world and like to abide by the rules :slight_smile:

In the past I would have put the country I was visiting as a suffix. It is much wiser, as most do, to put it as a prefix.

Sorry if it appeared to be a dumb question. It just caught me as interesting.

Just my two cents worth regarding “/M”. I read somewhere, in one of the ARRL publications (either one of the license manuals or their handbook), that “/M” is discouraged for indicating mobile because it could cause confusion due to the fact that “M” is also a country prefix. They recommended using “/MOB” to indicate mobile. In any case, I would interpret “M/” at the beginning of a callsign as indicating that the ham is operating in the UK.

73, Steve W6SAE

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Sigh. There are so many people who just don’t understand how amateur radio works.

Sadly it depends on whether you get to talk to someone who actually knows what they’re talking about. c.f. many threads about Ofcom and its left hand not knowing what its right hand is doing. Or even that it had a right hand.

But here’s a simple question to anyone. Give me one example of an amateur licensing authority that tells their amateurs they can sign Portable/CALL. And I don’t mean some country prefix but Portable/CALL?

i.e. P/MM0FMF

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Hi Steve - here’s another Gotchya -
enter /AM after a callsign for Aeronautical Mobile at and it reports the station as being from Spain. Putting dash rather than slash (i.e -AM rather than /AM) and everything is fine.

Perhaps this is something that the IARU should “try” to standardise - suffix versus prefix and whether /P or /M is actually needed any more - in some countries it’s optional, in others not.

Until then, care is needed…

73 Ed.

1 Like is simply broken. That is all.

Probably right Andy, but another question comes to mind - when Brian WB6RQN was flying over e.g. Oman - should he not be prefixing his call with A47/ or is there a ruling once you are above a certain height, its like being in “international waters”?

Everyone is trying to complicate matters as usual or throw in out of context comments.

Where in the world can you sign Mobile/MYCALL or Portable/MYCALL or Maritime Moble/MYCALL/P?

Hint: Nowhere maybe?


Propagation is bad and there’s nothing on tv. So the next entertainment is the sota reflector.

Reminds me of the python (?) sketch where someone opens a door and asks a question, only to be contradicted. Then they work out that the caller opened the wrong door. Oh you want arguments, that’s down the corridor. This is contradictions. (I probably have it wrong in the detail, but that’s the general principle - no problem, fifteen corrections will be made).

I think very few licensing authorities are interested in what hams say on the air. They are too busy auctioning the rest of the spectrum.

73 Andrew VK1DA VK2UH

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True. Jack’s (GM4COX) idea to push some microwave action has been wonderful. Now I can go and play HF and be disappointed because it was rubbish and then go and work a random contact on 13cms. 30hrs later I’m still smiling.

And the correct response to your “Is the right room for an argument?” is…

“I’ve told you once!”


The FCC only requires a suffix in a few cases. If you have passed the test for a license upgrade and are using those new privileges, but they have not been registered at the FCC yet, you use a suffix. After I passed my Extra exam, I ID’ed as K6WRU/AE for a few days. The “AE” is for “acting Extra”.

The rest of the rules for “indicators” are:

Each indicator must be separated from the assigned call sign by a slant (“/”) or any suitable word that denotes the slant mark (“portable,” “stroke,” etc.). If the indicator is self-assigned, it must be included before, after, or both before and after, the assigned call sign (example “KP2/W1AW/contest”). No self-assigned indicator may conflict with any other indicator specified by the FCC Rules (such as “AA”, “AG”, “AE” or “KT”) or with any prefix assigned to another country (such as “DL”, “F”, “G” or “VE”).

“KT” is used for upgrade to the Technician license. “AT” would conflict with India.

Incidentally, this answers a previous question. Under FCC rules, it appears to be legal for me to ID as “portable/K6WRU/portable”. Because no country has the “P” ITU prefix, I could instead have that before or after or both. “M” as a self-assigned indicator is not allowed, because that is an ITU prefix.



However, a couple of days ago I worked CT8/DH2IW. Where was he? Not Portugal! He was in the Azores, even though permanently resident stations in the Azores always use the CU prefix. CT8 is, indeed, listed in the CEPT regulations as the correct prefix for the Azores when one is temporarily operating there.

Walt (G3NYY)

This would seem to preclude the use of /M as an indicator for “mobile”, because the letter M is a prefix assigned to England.

Walt (G3NYY)

When I operated from the Bahamas on two occasions recently, my temporary licence had my callsign printed on it as G3NYY/C6A and I was directed by the local regulator to use exactly that callsign on the air.

Walt (G3NYY)

Yes, I said that in the post. As I read the FCC rules, “/M” is not allowed. Same for “/MM”, and for “/AM” (aeronautical mobile, conflicts with Spain). Of course, that is only for FCC-regulated operation.