Sign in a radio booth (2,3)
I believe the answer is:
on air
(Other definitions for on air that I've seen before include "Transmitting now!" , "now showing" , "In the process of broadcasting on radio or TV" , "Radio show might be" , "Cushioned" .)
I believe the answer is:
on air
(Other definitions for on air that I've seen before include "Transmitting now!" , "now showing" , "In the process of broadcasting on radio or TV" , "Radio show might be" , "Cushioned" .)