Most of the previous examples have been of large and middle market stations, so for a small market example, WENK of Union City, TN, was "K-radio" as far back as the '70s. Sometimes, they were just "the K" or "the super K." They didn't come up with the more obvious phonetical pronunciation of their calls ("wink") until sometime later, probably the '80s. When they added an FM station in the early '80s, they wanted to call it WENK-FM, but apparently the FCC wasn't allowing that at the time, so they went with WWKF, aka "KF-99." The WKF apparently stood for "west Kentucky, Fulton," for their COL. Their legal ID for that first year or so was also sort of confusing: "WENK-FM of Union City, Inc., presents WWKF, Fulton, KF-99." It gave the impression that their nickname was derived from "WENK-FM," even though the legal ID clearly gave their calls as "WWKF."
A competing FM station in Union City has called itself "KYTN" for many years, even though those have never been their actual call letters, and being east of the Mississippi, they probably couldn't legally adopt those calls, anyway. Their actual calls (at least during the time that they were nicknaming themselves KYTN) were WKWT (west Kentucky, west Tennessee) and now WYVY. They were calling themselves "Y-105" after adopting the WYVY calls, but under new ownership, reverted back to KYTN, although keeping the WYVY calls.