Originally there was a WRRR in Rockford, Illinois. When my FM signed on, WRRR was something else, and the call was available--but it was issued to us as WRRR-FM. Then a few years later, the AM station in Illinois--some 600+ miles away from us, asked if they could go back to WRRR (which we agreed to do) and they used that call again for several years, before changing yet again.