Demystifying Amateur Radio Callsigns

Regular Hackaday readers will be familiar with our convention of putting the name, nickname, or handle of a person in square brackets. We do this to avoid ambiguity as sometimes names and particularly nicknames can take unfamiliar forms that might be confused with other entities referred to in the text. So for example you might see them around [Bart Simpson], or [El Barto]. and occasionally within those brackets you’ll also see a capitalised string of letters and numbers after a name. For example the electronic music pioneer [Bob Moog, K2AMH], which most of you will recognise as an amateur radio callsign.

Every licenced radio amateur is issued one by their country’s radio authority as a unique identifier, think of it as similar to a car licence plate. From within the amateur radio bubble those letters and numbers can convey a significant amount of information about where in the world its user is located, when they received their licence, and even what type of licence they hold, but to outsiders they remain a mysterious and seemingly random string. We’ll now attempt to shed some light on that information, so you too can look at a callsign in a Hackaday piece or anywhere else and have some idea as to its meaning.

[Bob Moog, K2AMH]. PD, via Wikimedia Commons.
[Bob Moog, K2AMH]. PD, via Wikimedia Commons.
Happily for the would-be callsign spotter, there is an internationally agreed format for amateur radio callsigns. It does have occasional edge cases and exceptions, but the chances of encountering them is slim. There will always be a prefix of up to three alphanumeric characters which identifies a country or territory, followed by a single digit, and then followed by up to four characters.

Returning to [Bob Moog]’s callsign [K2AMH] above as a straightforward example, the “K”  is one of the prefix letters A, N, K, and W so far used in the ranges assigned to the USA, the “2” indicates that the callsign was issued in New York or New Jersey because the digit in a US callsign represents a region, and the “AMH” is a sequentially issued string of letters acting as a personal identifier. In more recently issued callsigns this will often be a vanity string, perhaps the operator’s initials or similar.

A seasoned callsign-spotter would also be able to tell you that [Bob Moog]’s callsign originates from sometime in the 1950s, as that was the period in which they started issuing single-letter “K” callsigns, and that it denotes a full or advanced class licence because the “K” is not accompanied by another letter. The FCC provide a handy guide to the callsigns they currently issue, if you are curious.

The Details

[Bob Moog] provides us with our straightforward example above, but as is so often the case there are many exceptions and international differences that mean not all callsign components have the same interpretation. For example in British callsigns the number does not represent a region, instead for the vast majority it conveys the age of the callsign and the class of licence for which it was issued.  If you are digging that deep into the information contained within a callsign issued in another territory, you will often have to resort to your favourite search engine.

[9K2/VO1DZA], a Canadian licencee working 30m WSPR in Kuwait, showing the Kuwaiti prefix in front of the Canadian callsign.
[9K2/VO1DZA], a Canadian licencee working 30m WSPR in Kuwait, showing the Kuwaiti prefix in front of their Canadian callsign.
Sometimes you will see extra letters with a slash at the start and end of a callsign. Letters at the start mean that the station is operating in another country or territory, for example.  Reciprocal agreements exist between countries allowing foreign amateurs to operate within their borders, when doing so they prepend the appropriate international prefix to their own callsign with a slash to indicate the true location of their station. Our example in the image to the left shows a Canadian station working this way in Kuwait.

Of course, not all radio amateurs work from home. There is a long tradition of portable operation, in cars, on foot, in boats, and even in the air. When operating in this manner there is a requirement to indicate this by adding a slash and an appropriate suffix on the end of the callsign. Thus you’ll see “/P” for portable or on foot, “/M” for mobile, and even occasionally “/MM” for maritime mobile and “/AM” for aeronautical mobile. There are tales for example of people working [King Hussein] of Jordan as [JY1/AM] from his royal jet somewhere over the Atlantic on the way to the USA. Incidentally that Jordanian callsign is one of those rare edge cases we mentioned earlier, it has no letters following its number. When you are king, the ultimate in vanity callsigns can be yours!

There is sometimes an undesirable side to being able to extract so much information from a callsign. People will always find an excuse to impose a hierarchy on any group, and radio amateurs are no exception. Thus you will sometimes find holders of older or more advanced licences excluding or being unpleasant to people whose callsigns they deem to be inferior to their own. We recently heard an oldtimer whose callsign reveals he was probably first licenced in the 1950s or 1960s rip into a recently licenced novice with a British M6 callsign, and it was not a particularly pleasant experience. We’re sure Hackaday readers will agree that it doesn’t matter when you were first licenced or what level of radio examination you have passed. You are only as good as the last piece of radio equipment you built, and the last station you worked with it.

We hope this has given you an insight into amateur radio callsigns, and they no longer appear to you as simply random strings when we feature them. If you are interested in amateur radio, you might like to see a previous feature we did on some of the steps required to take your licence exam.

Callsign plate header image: Cody gg 88 [CC BY-SA 4.0], via Wikimedia Commons.

61 thoughts on “Demystifying Amateur Radio Callsigns

  1. Good timing, I was just monitoring JT65 on 7076kHz with my RTL-SDR dongle this morning. Now, augment your post with more information regarding the prefixes used for other countries! So far this morning I’ve seen Japan, China, Indonesia, Mexico and Canada (along with USA, of course)

  2. Vanity call signs don’t throw the guide out the window. You still have the proper national letters and regional numbers. Some folks keep the call they got at a lower license level. Each multi state region in the US only has about 4000 1×2 calls like mine, K6BP. So they are only issued to Amateur Extra licensees, and many with that license must wait for one or never get one.

  3. Fun fact:
    Amateur radio prefix letters (A, K, N, W) are similar, but not identical, to ICAO aviation registration prefixes. They were assigned in parallel, by different agencies, but the big guys got the short ones in both cases.

    So, Australia is VK for hams but VH for aircraft. You can often trace the former colonies by their registration prefixes. V prefixes for former British, F for former French (except, sometimes, they petition to have those changed). The newly independent countries get the leavings (except in special cases: Pakistan gets PK from the ICAO, but AP for amateur radio)

    1. I’m not sure that’s true.

      Every country gets a block or blocks of prefixes. And each country allocates to the different services. So in Canada broadcast radio and tv get callsigns starting with “C”, while hams get VE or VO callsigns. But then next year we can be CF or CG. When CB required a license here, the prefix was XM. US broadcast radio and tv use W or K, as does ham radio, but then when they ran out, N and AA became prefixes for US hams.

      Former colonies may have had distinctive prefixes, and got to keep them when independent.

      I just don’t see any sense to the allocation.


  4. But then there are special callsigns, issued to specific hams or clubs for some event. Sometimes the whole country gets a special prefix (though use tends to be optional), like the US in the 1976 bicentennial year, or here in Canada next year for the 150th anniversary of Confederation. So VEs become CGs, though I have no idea what that stands for. The more recent VA calls become CF.

    But often these callsigns don’t fit the standard, so it can look like something exotic when it isn’t. Or rather, the callsign is exotic, but the location isn’t.


  5. Back in the day the bar was set relatively high for entry into the ranks of amateur radio, moreso arguably in countries outside the U.S., but even there licences were not given away. Of course this created an elitist culture and it is understandable (although not acceptable) that those that paid their dues are not that happy with newcomers getting an easy ride in. But the service would not likely have survived without new blood, and it should be kept in mind that getting a ham ticket was made hard largely to protect commercial telecom interests even though it was framed as a national security issue.

    1. Re: national security — I had a (recently deceased) friend, who passed his amateur license test in early December, 1941. He then spent five years as a US Merchant Marine radio operator on North Sea convoys, and only received his call, W1NXC, in 1945, after the end of the war. He was prohibited (as were all US hams) from operating for the duration…he said some transmitters were actually confiscated or disabled by the FCC.

      RIP, Ed.

        1. Wartime is a special circumstance, of course, and all forms of communication are restricted to some extent for the duration. However, in peacetime, there is little justification for these measures as those with nefarious intent are more likely to use clandestine means of passing messages. Open, simple two-way communication in the clear represents no threat except to the revenue streams of toll-seekers.

          1. War time is not the reason communications are prohibited by ham operators. Any country can declare that its amateurs can’t communicate with certain other countries. Many of the Middle East countries used to prohibit contacts with Israel (4X or 4Z calls). It is possible they still do.

          2. Well technically they’re at war (declared or undeclared.) US hams couldn’t work any of the ex-Indochinese countries during the Vietnam conflict. That’s not the point I was making – amateur radio was (and still is to some extent) inhibited where it poses a competitive threat to commercial telecom suppliers.

      1. I somewhat recently read that in the US during WW II, while there was a general ban on Amateur radio activity; Some stations would be permitted to operate under some circumstances. I can’t recall where I read that, perhaps in one of the old QST reprints in QST during the ARRL centennial year, I’m not sure.

        1. There was the WERS (War Emergency Radio Service) on the 2.5 and 1.25 meter bands operating during the WWII era. WERS licenses were given to communities and not individuals. One of the requirements for individuals to participate in the WERS was to hold an Amateur radio license. WERS was to provide communications in connection with air raid protection.

    2. “Amateur radio” predates radio laws. As laws came into being, because specific things were found to be useful (like ship to shore radio), amateur radio followed long, with more restrictions. Not to “protect commerce” but to ensure no interference. Once again, amateur radio is the one “service” that is wide open, bands of frequencies rather than a specific channel, build your own equipment, try new things. That’s why the testing, to ensure that someone will be careful and not interfere with communication while the Titanic is sinking.

      What’s changed is that more and more people thought amateur radio was primarily about “talking on the radio”, so the testing opened up. Not to be “egalitarian” but since fewer were building why have technical tests?

      Since 1990, in Canada you can’t even use a home made transmitter with the basic license. That dramatically changes the service. When I was licensed, it was still the “Amateur Experimental Service”, and the basic license allowed for everything except voice on the lower bands. That’s incredibly free, in exchange for the testing.

      When I first learned of amateur radio, I couldn’t get a license. In Canada you had to be fifteen or over, that’s discrimination. It was at least five years in the future, so I just soaked up anything I could about electronics and radio, rather than “study for the exam”. Then just after I’d turned twelve, the news came that the rule was going away. I joined local code and theory class in February (it had started in September) and took the test in May, the first month of the new rule. I did fine on the theory stuff, I failed the morse receiving test. A month later I took the code test again, and passed. It was the last week of grade six for me. I was likely the youngest ham in Canada, though because the rule had just changed.

      How can a test be too complicated if a twelve year kid can pass it, and without a lot of deliberate study?

      People didn’t want to fuss with code, and they didn’t want to fuss with “technical stuff”. So they stayed out until the hobby became something else.


      1. If the licencing requirements hadn’t relaxed, there likely wouldn’t be an amateur radio service today. Frequencies in the VHF and above in the allocation would have gone to other users for sure if the number of hams had dropped any farther. I also doubt that without the availability of relatively affordable commercial rigs that the hobby would grow either on HF.

        1. | If the licencing requirements hadn’t relaxed, there likely wouldn’t be an amateur radio service today.

          Sadly, that just speaks to the dumbing down of this country (USA) if not society as a whole. Something is “too hard” for the masses, so we make it easier. Same with school… kids can’t read, write or perform simple mathematics so rather than actually teach these kids, what do we do? We relax the testing and curriculum to the point where kids are “graduating” from high school unable to read or write simple content and couldn’t add 2+2 without their “smart”phone. This isn’t an exaggeration. I have several younger friends with high school diplomas (which is more than I can say for myself) and they couldn’t read this post without GREAT difficulty! My niece and nephew are the same way. I may not have graduated, but it wasn’t due to inability. It was due to I didn’t care. Besides that, even in eighth grade, I was doing some of my aunt’s college course work for her.

          I didn’t get my ham license until a couple of years ago at age 40, even though I’ve been a (self-taught) electronics technician for 30+ years (including working with my dad back when I was a kid) – not because I couldn’t or it was “too hard” but because, like high school, I didn’t care. I never talk to anyone anyway.. I just wanted to prove to myself that I could. I took it as a challenge.

          To today’s generation, a “challenge” is standing still for a photo shoot (the “mannequin challenge”). Instead of making things easier, kids (and some adults) need to learn discipline and real learning.

          But that’s just my take.


          1. On the other hand, the spectrum represent a public resource and needs to be managed to the benefit of as many people as possible. Maintaining artificially high standards to their use simply because it satisfies the egos of a small minority with elitist notions is simply unsupportable. The continued health of the service depends on maintaining a certain level of active users and if they aren’t there it is going to be hard to make an argument that these frequencies should not be reassigned.

          2. At one time, radio was just about the only outlet for people with an interest in electronics or pretty much anything engineering related. Today, there are many outlets for that sort of interest, so interest in ham radio decreased.
            With the lowering of the entrance requirements, ham radio started to attract people who were interested in communication more than the engineering aspects. I remember hearing a lot of people on two meters who worked as dispatchers, etc. and got their license after the code requirement was dropped for technician class. These people are often great assets in times of emergency.
            Yes, ham radio has changed, but some of it is for the better.

          3. I am the founder of No-Code International, the organization that lobbied for the end of code testing internationally, and eventually got it. I passed a 20 WPM test given by ARRL VECs before I got the call K6BP, but did not use Morse code on the air until the requirement was gone.

            We can’t really call removing a Morse code test “dumbing down”. There’s not really anything about Morse that means you are more educated, smarter, or more technically capable. It just means you can communicate competently using the most primitive form of modulation, interrupted-carrier radios, when other people might use radiotelephone, PSK31, etc. And of course all hams can still use CW, they just don’t have it on the test any longer.

            I would actually have been for an increase in the technical test, and would still support one now, but that has not been generally supported by the Amateur community.

            We were watching the decline in Amateur licensees, and we could see a point where ham radio would end, and it was in our own lifetimes. That’s no longer the case. We didn’t just win for no-code, we won for all of Amateur radio.

          4. I can’t seem to reply to replies to my comment so I’ll just post this here. I don’t mean the removal of the Morse code requirement. I couldn’t have passed that myself. I am only talking about the technical aspects of the tests,

      2. Home constructed amateur constructed and field constructed commercial transmitters still can interfere with other licensed radio service. perhaps that why passing exams is still required to acquire Amateur and commercial licenses. I really doubt few could pass a written amateur radio license exam without deliberate study.

  6. The form of the callsign being related to the license class has changed over the years. At the time K2AMH was originally issued, it could have been issued to any class other than novice.
    The requirement to get a new callsign if moving from one call area to another was eliminated in the late ’70s, so the number now only indicates the call region where it was issued, not the current location. (and, in the case of vanity calls, not even that)
    Another complication is that a ham can keep the existing callsign when upgrading.
    For example, my callsign, WB6OTG, was issued in California in 1976 when I got my technician license. I’m now living in North Carolina and have an advanced class license, but I kept the original callsign.

  7. For me, my initial callsign meant nothing to me. I initially gained my technician class and issued KF6TYO. As a child, I tried learning Morse code but d spite learning and forgetting much of alphabet through many attempts to learn, I can’t consentrate on the series of dits or dashes for any longer than 30 seconds. This heals me back from an advanc d class of license until requirement for code was eliminated. I then passed all the tests for Extra. As a “reward to self”, I wanted a callsign that meant something. I settled on an “Advanced” vanity call of [WE6BB].

        1. I thought a handheld counted as mobile, with the /p used to designate a fixed station not at your home QTH?
          I recall some discussion, back when /m and /p were required, about whether to change from /m to /p every time you stopped at a light. The decision was to stick with /m

        2. Yep, one time coming home from a camping trip on Stradbroke Island… I was VK4MSL/BM briefly, then VK4MSL/MM, then VK4MSL/BM again then VK4MSL/RRM then VK4MSL/BM.

          I was dropped off at the ferry terminal, travelled by ferry across Moreton Bay to the terminal at Cleveland, rode to the train station, caught the train to Roma Street then rode home from there.

  8. By international agreement, each country’s radio calls start with a letter from an assigned set of letters. The letters that can start US radio calls can start with W, A, N or K, which makes me suspect that the British had something to do with the letters chosen for the US….

    1. That is brilliant… never noticed that myself.

      I’ve spoken to a few Americans that are decent people, but every country seems to have that small minority that makes the rest look bad.

      (Moderators, please ignore that “Report comment”. I haven’t had my morning cup of tea yet so brain wasn’t working properly, thought it was the permalink link!)

    2. Haw!!! I never noticed that either.

      The actual explanation is much more prosaic. Originally, we picked A and N for Army and Navy, and then added a dash to get W and K.

      Jay, K5ZC

  9. And lets not dig into all those special-event calls, in the beginning they were fun to chase and get a diploma for, but it seems today there is specialcalls for every russian saint, every bigger sporting event, every city celebrating a jubile, and a lot of other events.

    With that said, I once ran a special event call, and it was fun for a while to be hunted on the bands, atleast until the hunters started to email and demand scheduled contacts to gain points on their diplomas :D

    Actually they were all good sports and mostly asked for when they was mst likely to hear me on the bands (due to work hours and such) and the emails was mostly “Thanks for a new band, when will you be on another?”

    Once the signal was spotted on the cluster it was non stop action, and I even lost my voice on occasions.
    I think I made a bit over 9000 contacts with that special call, and the QSL cards are still flooding in.

    Would I do it again? Probably not, atleast not in the near future, am I glad I did it, sure, it was fun.
    Should others try it, absolutely, atleast once.


  10. I’ve had my license since 2001 and still keep my original callsign. Currently I hold a General class license. I am currently studying for the Extra test but I’m doing it the ‘long’ way. By that I mean I usually get passing grades on the practice tests already but I am trying to BOTH memorize AND completely understand the meaning and background material of every question and it’s answer. At this rate it’s going to take years. That’s ok, I’m in no hurry.

    I haven’t been on HF much yet except for on Field day using the club call and a little on 10M FM since my mobile radio does that. My goal is not to have a home HF station until I have built it myself. I do have a 20M trasciever I attempted to build from a kit but it has transmitting problems.

    Anyway… 2001 was a completely different time in my life. And.. I’m kind of a nostalgic person. I like my old call and have no desire to change it. I have happy memories associated with it. So.. when I do get on HF if some tired old appliance operator doesn’t want to talk to me because I have a ‘tech’ call… well… I doubt that’s my loss.

    Then again… at the rate I’m going… maybe by the time I am really present on HF my 2001 era call will mark me as an elmer…

  11. >>Every licenced radio amateur is issued one by their country’s radio authority as a unique identifier

    Just to be picky (someone will probably correct me on this – e.g certificate =/= licence)..

    This only applies to certain radio licences. I have a Canadian Restricted Operator Certificate (Maritime) and no call sign; the call sign is the name of the boat I happen to be on.

    On another note – my uncle was a ham and I remember listening to broadcasts in his radio shack as a kid. It was amazing when I was 8 years old. I never got the hang of Morse code (in scouts I was better at flag semaphore than Morse). It was always in the back of my mind to get into it, but I never have. I respect what you guys do.

  12. Kansas in one of those States where on can have the same call on passenger vehicle and on truck. In Kansas we choose choose to leave of the County denominator off or call sign plates. Surprising how many people notice that and sound pissed off when they learn it’s optional for me. I haven’t never inured if I could use may call with a an appended (-##) for additional vehicles. Not relevant now, because I can afford only one vehicle these days. On evening a headlight burn out on my way home, and was stopped By law enforcement. I heard dispatch say record not found. I comment you said “O” instead of zero, correct? Not that most of law enforcement in this rural county knows me and my vehicles anyway. A resident since I was 6 months old, storm spotter, RACES, Red Cross and so on; it’s not like I’m hiding out.

  13. Being an engineer, I lucked out with my call-sign. Older hams say it as Kilo Cycle Eight Kilo Volt Amps…which, is perfect for ham radio techies like me. My wife (the camper, active grandma, video game player) got another luck of the draw as well…Kilo Delta Eight Real X-treme Mama. All in all…I love the hobby, and will continue with it in (and out of work) when I can. 73 everyone from KC8KVA (and KD8RXM laughing in the distance.)

  14. But you know what? Those “K” and “W” calls that the author says show that the holder was licensed in the 50s and 60s? That ain’t necessarily so… For instance, I’m K7DGF, if you assume what the author says applies here, you’d be wrong. What I have is a “recycled” call. Somebody else held the call waaay back then, then they either died, or just failed to renew, and after a period of time (I forget what the exact time is) it can be reissued, in which case, since I’m an Extra class licensee, and my initials are DGF, I was able to get that call in 1998, when I upgraded to Extra from my previous Tech+ license, releasing my old “WA6QNW”…. Another pretty LARGE “edgecase”, but a good primer otherwise on ham callsign info…

    1. Once a call sign is marked inactive, it can be reassigned in two years and one day. There are exceptions if the holder of the license dies and a family member with the proper privileges wants to get the call sign to “keep it in the family.”

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