Broadcast race, then hack (7)
I believe the answer is:
relayed
'broadcast' is the definition.
(I've seen this before)
'race then hack' is the wordplay.
'race' becomes 'relay' (relay race).
'then' means one lot of letters go next to another.
'hack' becomes 'ed' (hack can mean journalist, ed short for editor).
'relay'+'ed'='RELAYED'
(Other definitions for relayed that I've seen before include "Broadcast; passed on" , "Received and passed on" , "Passed along" , "Transmitted along" , "Layered (anag.)" .)