Why Do Radio Stations in the US Begin with K or W?

Why Do Radio Stations in the US Begin with K or W?
If you are at all familiar with radio, you might have noticed that radio stations throughout America identify themselves with four-letter sequences, and these typically start with either a K or a W. There was even a TV show from the late 1970s called “WKRP in Cincinnati.” Have you ever thought about why this is though? Why do radio stations in the US begin with K or W?

The History of Call Letters

Before we begin to dive into the letter K and W, we need to determine why these short letter sequences matter in the first place. The answer to this question goes way back — in fact, clear back to telegraphs. When telegraphs were used as communication, small letter sequences were used to identify information.

In 1912, a large conference took place on International Radiotelegraphs. This conference discussed how to identify radio signals and their originating country. To solve the problem, each country was assigned specific letters to identify themselves. The United States was given four letters: W, K, N, and A. The letters W and K were assigned for commercial radio use, while N and A were assigned for military radio use (if you’re curious, Canada was given C and Mexico was given X).

To help regulate and license commercial radio stations in America, a boundary was drawn in the United States. This boundary would change over time, but essentially one half of the country was given K, while the other was to use W. Eventually, the Mississippi River came to be the dividing line. Radio stations that were located to the west received the call letter of K, while those in the east received W.

Why do we even need call letters today? Broadcast call letters are meant to serve as unique identifiers for radio and television stations. Radio stations will often brand themselves with plain-text names (“cool FM” or “rock 105”), but another station in another city or country may have a similar brand. So call letters are used to distinguish each individual station from one another.

There Are Some Exceptions to the Rules

Just to complicate matters, not all stations follow these exact call letter guidelines. This means that you may still hear radio stations on the west coast have call letters that begin with W. This is because when the boundaries changed in 1923, not all radio stations were required to change their call letters. Today, it is not uncommon to come across a few stations where geographically, they fell in the gap and did not change their call letters. However, this is becoming rare. Additionally, there was a short period of time where all new radio stations were given the letter K, regardless of their geographical location.

These exceptions may also be intentional and for marketing purposes. Owners can make special requests for call signs that may not conform to the rules. For example, WACO is located in Waco, Texas, but it should technically have the first call letter K.

Additionally, you may notice that some call letters only have three identifiers, or the letters do not follow the rules. These are typically older, more traditional names that were picked at a time when stations were allowed to choose three or four letter combinations.

Now, the next time you turn on the radio and begin listening to your favorite radio host, you’ll know where the famous K or W came from.