Call sign trivia

More totally useless info:

You’ve undoubtedly heard that station call letters must begin with W east of the Mississippi and K to the West. While this is usually true when new stations are assigned call letters, it was not always that way.

Why do some areas have stations with both K and W prefixes? Three reasons: (1) they moved the border in 1923, so some areas between the Mississippi River and the extended Texas / New Mexico border have been in both the W area and the K area when new call letters were assigned; (2) there was one year in the 1920s when all new stations had to start with K, so it is theoretically possible to have a K station far east of the Mississippi if they were assigned their call letters in that brief period, including several such stations in Pennsylvania; (3) some stations applied for and received an exception, like WACO in Waco, Texas. Here are some exceptions to the Mississippi River rule.

While all broadcast call letters in the USA begin with K or W, they theoretically could begin with N or A as well. So far, the N and A have only been used for military broadcast stations.

New stations must have at least four letters in the call sign. No more “WGN,” for example. One commenter noted an exception:  “If a radio or TV station is co-owned with another station with a three-letter callset, it can adopt those same calls. That’s how Baltimore got WJZ-FM in 2008, for example.”

Some call signs are as long as seven letters.

While almost all Canadian stations begin with C, there are some in Newfoundland that begin with V. (Those were assigned before Newfoundland/Labrador became a province in 1949.)