This has been around pretty much since Ceasar was assassinated - well, maybe not quite that far back;-).
Anyway, they are STL's - "Studio Transmitter Links". Very common in the past for radio broadcasters to use these frequencies for "live on-scene" remote broadcasts back to the studio for relay on the regular broadcast frequency. TV stations use them more for remote location away from the studio "IFB" which is "Interruptable FoldBack": Interruptible foldback - Wikipedia, the free encyclopedia
There are several VHF and 2MHz worth of UHF frequencies set aside for this type of operation. They can also be used for normal two-way use by the broadcast studios to coordinate with their remote mobile units.