Deciphering U.S. Amateur Radio Call Signs

Did you know that there are some basic bits of information you could gain from someone’s amateur radio call sign?

From one’s call sign, you can often learn the general area of the country where the ham is based, you can get an idea of his or her license level, and you can sometimes guess about how long he or she has been licensed.

Just so you know up front, this is not 100%. There are many exceptions found, but call signs can give some clues in many cases, if you know how to decipher them.

For starters, U.S. call signs are divided up into 4 groups. The groups are then further divided into classifications based upon their formats. The formats of call signs reflect where and how many letters appear around one number. There is one number (and only one number) in every U.S. amateur radio call sign, and that number is significant. It identifies the general area of the country where the ham operator first obtained his or her license. The map below identifies the numerical areas for call signs in the lower 48 states.1 (Outside of the lower 48, U.S. call signs use different area markers. Alaska call signs begin with “AL,” “KL,” “NL,” or “WL.” Call signs from Hawaii, Guam, American Samoa, or the Northern Mariana Islands begin with the designations of “AH,” “KH,” “NH,” or “WH.” Finally, any call signs from Puerto Rico or the U.S. Virgin Islands begin with either “KP,” “NP,” or “WP.”)2



Again, just so you are aware. This is a general guide. There are many exceptions. For example, an operator may move from one location to another but still choose to retain his or her call sign. Also, other exceptions exist when operators choose to apply for vanity call signs that are generally reserved for other areas of the country. If you are not aware of the definition of a radio vanity call, it is much like choosing a vanity license plate for a car. One may choose which letters may appear as long as it is available, and as long as it follows certain FCC guidelines for call signs.3 For example, one may not apply for a call sign which is not designated for his or her amateur license level. This brings us back to the four classification groups, which, if one identifies to which of the four groups a call sign belongs, one may get a good idea of the level of license held by the call sign’s holder.

As said before, there are four groups of call signs, each with further divisions based upon their formats. The first group of call signs belong to Group A. Only those with Amateur Extra operator licenses may apply for signs in this group. These signs take one of three forms: 1×2, 2×1, and 2×2. That is, they can have the forms of “one letter, one number, two letters,” or “two letters, one number, one letter,” or “two letters, one number, two letters.” The first two formats begin with “K,” “N,” or “W,” (or “AA”-“AL” for some 2×1 signs,) and signs of this group with the third format begin with “AA”-“AL.” Any call sign which belongs to this group would identify the operator as an Amateur Extra license holder, which is the highest license level granted in the United States. There are very few exceptions to this rule, (besides some “AH” or “AL” 2×2 calls which are also found in Group B,) so it is a safe bet that if you ran into one of these call signs on the air you may assume that the operator was indeed an Extra.4

Group B call signs all have the format of 2×2, that is, “two letters, one number, two letters.” Instead of beginning with “A” (which prefixes are reserved only for Amateur Extra operators,) the calls of Group B begin with “K,” “N,” or “W.” The exceptions to this rule would be the “AH” 2×2 Group B calls that are available to U.S. Pacific island residents, and the “AL” 2×2 Group B calls which are available to Alaskan operators. Group B call signs are usually only available to Amateur Extra and Advanced class operators. (Advanced is a grandfathered license level which is no longer issued to new licensees.)

Group C call signs are identified by its 1×3 format: “one letter, one number, three letters.” These signs begin with “K,” “N,” or “W,” and they are available to all except Novice level licensees. (Novice is another grandfathered license which is no longer issued to new recipients.) Even though Technician holders may hold a group C call sign, the majority of those with these call signs are General class operators or above.4

The last group, Group D, is for call signs with a 2×3 format. Thus, they have the format of “two letters, one number, three letters,” and they begin with either a “K” or a “W.” This format is, by far, the most common in the U.S. as there are almost double the amount of Group D call sign holders than of all of the other groups combined.When someone becomes a new ham, they are first assigned a system generated call sign from this group, and often hams will just choose to hold onto their original call even after they choose to upgrade their licenses. Because of this, license levels cannot be accurately predicted with a Group D call sign. However, because new calls are generated systematically by the FCC, one can get a good idea of how long that an operator with a Group D call sign has been licensed. This is because if you identify the letters and the number within the call, you can estimate the length of time based on what calls are being assigned currently to the geographical area assigned to that number.

Again, just as was mentioned above, there are many exceptions to these general guidelines. But overall, one can glean some information from a call sign in many cases. True, this information would likely not increase or affect your chances of survival, but if you are a practicing ham as I am, it may be information interesting enough to try to guess.

  1. US Amateur callsign regions” by Blank_USA,_w_territories.svg: Lokal_ProfilChrisRuvolo (t) – based on Blank_USA,_w_territories.svg; Source data: [1]. Licensed under CC BY-SA 3.0 via Commons.


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