Hello,
I'm attempting to track down the format(If any), that's used to announce the opening and closing of the business day, at various part-time ATC facilities. I suppose one for an unexpected closure of a 24/7 facility might be good too, although I'm guessing this widely varies from one place to another, and heavily depends on the circumstances, level of closure, etc.
If anyone recalls of the top of their head what they hear/heard, during an encounter with such an announcement, please either post here or send it to alex [at] pilotedge [dot] net.
Much appreciated!
Alex