Raleigh area..
Our ABC affiliate broadcasts ch.11 analog, ch.52 digital.
Apparently when they go all digital they are going back to VHF ch.11.
Complicates antenna design.
A knowledgeable friend (in the business of building DTV facilities) says that hi-V (channels 6-13) is exceptionally good for ATSC transmission.
He’s never mentioned having to put in a new antenna for ATSC to replace one that served for NTSC on the same channel.
(Of course there are other reasons to replace a broadcast antenna, but switching to ATSC on the same channel does not seem to be one of them.)