Why W and K in radio & TV call letters?

Radio and TV station call letters east of the Missippi begin with a “W” and those west of the Mississippi begin with a “K”. How did the FCC happen to choose those particular letters of the alphabet?

I think Cecil may have addressed this at some point, but am too lazy right now to do a search. In any event, those letters were assigned to the U.S. by international treaty in the early days of radio. Other countries have different initial call letters.

The FCC didn’t choose them, it is part of an int’l treaty assigning various alphanumeric combinations to broadcasters to identify the nation of origin and avoid confusion (remember, we’re talking many years ago, shortwave, etc…)

US radio got W***,K*** and N***; France got F***; The UK got GB*** and GK***; Brazil got PJ7***; smaller nations got things like 7X***, etc…

As more types of transmitters arose, newer combinations and lengths were introduced, like police broadcast stations (KMA4465, et al.) and so forth.

O le mea a tamaali’i fa’asala, a o le mea a tufanua fa’alumaina.

Too cool, Jorge! Do you have a citation or a link? That’s lovely History of Communications fodder.


IIRC, at first all broadcast stations in the USA began with a W. Later, they decided to split the US by the Mississippi and only assign W’s in the east and start assigning K’s in the west (to handle the increased amount of broadcast stations–like adding new area codes to major cities). Thus, you’ll notice that all the “W” stations left in the west (WBAP in Ft. Worth and WRR in Dallas come to mind) are also especially old stations. I don’t know how it’s doled out these days–I think everybody new gets a ‘K’.

Jorge’s right… why K and W? It’s just sorta arbitrary. Mexico’s got X and H. One of my favorites out here is “hache hache e hache” (HHH) de Ojinaga, Chihuahua!

That’s what that was! I had a friend from Chihuahua with an HHH sticker on his car. Always thought it was the Mexican branch of the Illuminati . . . :wink:

There is a station in Pittsburgh called KDKA. It is the oldest commercial broadcast station in the world. Any ideas as to how it came to have and keep a K?

“Shoplifting is a victimless crime. Like punching someone in the dark.” -Nelson Muntz.

From the KDKA radio website,

Other things on this website indicate that KDKA predates the FCC by a good bit. Their website’s at http://www.kdkaradio.com/ , if you’re interested.

Never attribute to malice anything that can be attributed to stupidity.
– Unknown

…and, of course, Canadian call letters start with C.

This sometimes leads to strangenesses and bizarrities in areas that can receive United States signals leaking across the border. In Totonto, there is a radio station CISS, that started out as “new country”, and advertised themselves as CISS (pronounced ‘kiss’).

They suddenly changed format, and in the spring promoted themselves as “KISS” FM 92-point-something. This led to confusion with radio station KISS-FM in Buffalo, New York.

I’m not sure what happened after that; I haven’t listened to the radio much lately…

http://www.itu.int is the International Telecommunications Union, but it will charge for any information you may want.
http://www.rac.ca/prefix.htm provides most that you’d need to know. Except what the call signs for various stations are - outside America they’re completely ignored.

I never knew any of this. Just shows what happens when you stick around these parts.


Cecil took a stab at this in Triumph of the Straight Dope, and, no doubt due to a horrible editing job by Little Ed, fell far short of his usual high standards. See:
Cecil’s Lousy Call Letter Answer for the gory details, plus answers to most of the questions people have brought up here.

Mexico generally has XE- calls for AM, and XH- calls for FM stations. Thus, I suspect “(HHH) de Ojinaga, Chihuahua!” is really officially “XHHH”.

whitetho == Thomas H. White == Cary, NC
Radio History page: http://www.ipass.net/~whitetho/index.html
Call letter review: http://www.ipass.net/~whitetho/recap.htm

I am in awe. Bravo.


I’m glad someone mentioned non-commercial radio call signs. They seem to be pretty much exempt from the W = east and K = west standard. Case in point: KCB615 is the FCC assigned call sign for the Swansea, MA Fire Department, on an assigned frequency of 153.950 mHz. We also have KCD890 (Warren, RI), KCC673 (Jamestown, RI), KAZ443 (Rehoboth, MA), etc, etc, etc. As for commercial broadcasting, see the prior posts, they pretty much sum it up.


I can think of no more stirring symbol of man’s humanity to man than a fire engine - Kurt Vonnegut

and actually, not all stations in the US are K or W…there’s a Detroit station, IIRC, that starts with a C…it was owned by Canadians (those bastards :slight_smile: ) and was grandfathered in. and a station in San Diego, i think, that starts with an X, for the same reasons, except replace Canadians, with Mexicans.

I think the initial call letter(s) abide(s) by where the antenna is located. I seem to recall, in my youth, receiving, in San Jose, CA, a 100KW AM station that blasted in, claiming studios in San Ysidro, on the US side of the border opposite Tijuana, but which had its transmitter, I think, in someplace in Baja California (now " " Norte) called Rosarita Beach. It was basically a US religious station, as I recall, which had its transmitter in BCN, because the US wouldn’t allow powers higher than 50KW, and only a few of those.

Ray (Almighty power bordering on the political)

I meant to note that the call letters of that station were XE–, I think XERB.


US is always A-something, K-something, or N-something, as per the treaty with the ITU (based in Switzerland - thanks Heretic, you beat me to it). Specificity beyond that if I’m not mistaken is nationally controlled, and “appropriate” sequences created by the friendly folk over at the FCC here in the US.

W and K used to indicate East/West of the Mississippi, in addition to regional numbers assigned (For example, with amateur radio: W1***= New England, K6***= California, for example, with special assignations for places like Alaska, KL7***). As the numbers of transmitters quickly began exceeding available alphanumeric permutations, N’s were allowed for other transmission types, then W’s and K’s were allowed to migrate East to West. This hasn’t quite happened with, say VHF TV stations , in the form of K*** or W***; UHF TV is usually K##*** or W##*, and both still follow the E-W rule last I noticed. N was typically aircraft and marine; K#### police and public safety; and so forth…

Canada starts with V, but perhaps as VHF developed, there was little fear of mis-identification between Ottawa’s, Prague’s and Switzerland’s evening news, they use C to begin a four letter call-sign; but I wouldn’t be surprised if there is some small disclaimer (like at the end of the day announcement, “this broadcast station VE3QUE” or some such).

More than you needed to know, probably…

O le mea a tamaali’i fa’asala, a o le mea a tufanua fa’alumaina.

Regarding the original post *Why the letters K & W??

I can see Canada having stations starting with a “C” and Mexico having and “X” [MeXico], but why W and K. In the USA there isn’t a W or a K.

BTW I believe people refer to Channel 6 in San Diego. That station may broadcast in English but it is assigned to Tijuana. It a long long long time ago was supposed to be an ABC affiliate but it caught flack with the FCC and protester. ABC since went with a UHF station. (Later that of coursed changed)

Speaking of which, San Diego got shortchanged in VHF stations. It is 6th largest city in the USA. LA should give it a few of its VHFs

ubermensch opined: and actually, not all stations in the US are K or W…there’s a Detroit station, IIRC, that starts with a C…it was owned by Canadians (those bastards :slight_smile: and was grandfathered in. and a station in San Diego, i think, that starts with an X, for the same reasons, except replace Canadians, with Mexicans.

Well, actually all U.S. broadcast stations do start with K or W. Of course, it is possible to hear stations from other countries in the U.S., using their own national callsigns, which is what you have here. A very popular station in Detroit through the 1980s was CKLW-800, but the station wasn’t located in the U.S., it was located in Windsor, Ontario. Likewise, some stations in Mexico near San Diego broadcast in English, except for their I.D. on the hour, when you’ll find you’ve been listening to XETRA or somesuch.

call letters (and the city of location) are based on where the transmitter is. that’s why WXLP (studio in davenport, iowa, is found under moline, illinois.) and a lot of stations from that area are like that. there’s been a lot of acquisitions in the past 10 years.

one search netted XHTZ in Chula Vista, CA. of course, i’ve also seen where it’s listed as being in Mexico. but according to their website, http://www.z90.com , their mailing address is in Chula Vista, but on one web page (at least) it’s listed as Tijuana MX, San Diego, CA. IIRC, the studios cannot be more than 20 miles from the transmitter, but i could very well be wrong.