@kindofblue
Users reported the issue if missing channels in OTA/antenna after an OS 11 update build.
Go into your OTA guide, navigate to the left where the channel numbers are, press * button on your remote, then Filter, Show all Channels.
That should make them reappear.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102