One has an excellent right to broadcast on it (3)
I believe the answer is:
air
'broadcast on it' is the definition.
(I've seen this before)
'one has an excellent right' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'an' could be 'a' and 'a' is found in the answer.
'right' could be 'r' (abbreviation) and 'r' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'to' is the link.
Can you help me to learn more?
(Other definitions for air that I've seen before include "voice giving > impression" , "Vent; atmosphere" , "coming through the open window" , "Space above and around" , "14" .)