The Why (and Where) of U.S. Radio's K and W Call Signs - Big Think

The Why (and Where) of U.S. Radio's K and W Call Signs - Big Think

"Quite early, the border between K Country and W Land had to be fixed geographically. But that dividing line lay further to the west than it does now: it followed the border between New Mexico in the west with Texas and Oklahoma in the east, then north along Colorado's eastern border with Kansas and Nebraska, Wyoming's eastern limits with Nebraska and South Dakota and finally Montana's with the Dakotas....

"A decade into the first federal regulation of station call signs, the K/W line was moved to the Mississippi, turning Texas and 10 other 'eastern' (W) states into 'western' (K) ones [8].

"After January 1923, new radio stations in the switchover states would be assigned a K call initial rather than a W one. But a grandfather clause provided that those radio stations in those states which already had a W call sign could keep it. This explains some of the anomalous call signs still in existence today, if not quite all of them."

WKY in Oklahoma City, WBAP in Fort Worth, and WOAI in San Antonio are three of the stations licensed before the line moved east.