The US radio broadcast given official sanction (10)
I believe the answer is:
authorised
'given official sanction' is the definition.
(sanction can mean to authorise)
'the us radio broadcast' is the wordplay.
'broadcast' indicates an anagram (letters scattered or cast around).
'the'+'us'+'radio'='theusradio'
'theusradio' is an anagram of 'AUTHORISED'.
(Other definitions for authorised that I've seen before include "approved" , "Commissioned" , "official" .)