Calling All Nerds

I've picked up a recent fascination with name spaces, specifically constrained name spaces like country codes, language codes, XML and other programming languages. But I always wondered why all four-letter TV and radio station identifiers started with either a "W" or a "K" like WKRP or KQED. Turns out that broadcast stations could begin with any letter of the alphabet but certain ranges were allocated to certain countries. For instance, the U.S. gets all sequences starting with "W" but only a subset of all sequences beginning with "K".