There were a lot of AM/FM/TV combos in the earlier years, but one by one, they were broken up ... in many cases, the radio station kept the calls, and the TV got a new set of letters ... logic was that radio was known by its call letters, and TV was known by its channel number, so its call letters were not relevant, as long as the TV could call itself "Channel _ " - didn't make no never mind - ... examples, WREC Memphis radio kept the calls, TV became WREG ... Nashville WLAC TV became WTVF but let the radio keep the calls.
One weird situation is WWL ... the AM and TV went to separate owners, but apparently the two licensees made some sort of deal that each one kept the calls ... and for a long time now, WWL AM and WWL TV had separate owners. Go figure.