Broadcast mike in a van (8)
I believe the answer is:
transmit
'broadcast' is the definition.
(synonyms)
'mike in a van' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' means one lot of letters goes inside another.
'a van' becomes 'transit' (Ford Transit van).
'm' placed inside 'transit' is 'TRANSMIT'.
(Other definitions for transmit that I've seen before include "Broadcast (a signal)" , "Pass on (message)" , "Send from one person to another, or broadcast" , "Communicate (an idea)" , "Send (a radio message)" .)