I am a new member to the Straight Dope forum and I have a question about this W/K call letter business. If the Mississippi River was established in 1923 as the dividing line for W in the east and K in the west, would radio stations west of the Mississippi River founded before 1923 have W as their first call letter?
I ask this because I know of several radio stations in the Midwest that are west of the Mississippi River with W as their first call letter. For example,
WHO in Des Moines, Iowa
WDAY in Fargo, North Dakota (founded in 1922)
WCCO in Minneapolis, Minnesota
As you may have guessed, this has been discussed before. There are several good posts and links to answer your question in this thread.
Basically, the original K/W dividing line was not the Mississippi River, but the border between Texas and New Mexico (and running vaguely north along state borders from there.) That would explain “W” stations in Iowa and North Dakota, since they are east of the original border but west of the current one.
This may explain 'CCO as well, but most people don’t even bother to count K/W exceptions in Minnesota and Louisiana because there are so many. Even among stations founded much later than 1923, you find many, many exceptions on both sides of the river, at least in the Twin Cities area.