Television transmission (9)
I believe the answer is:
broadcast
'television transmission' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for broadcast that I've seen before include "Transmit over airwaves" , "Transmit by radio or television" , "Send out by radio or television" , "Transmit (programme)" , "Put on the air" .)