Broadcast live with a mike (4)
I believe the answer is:
beam
'broadcast' is the definition.
('beam' can be a synonym of 'broadcast')
'live with a mike' is the wordplay.
'live' becomes 'be' ('be' can be a synonym of 'live').
'with' says to put letters next to each other.
'mike' becomes 'm' (phonetic alphabet: alpha, bravo, charlie etc.).
'be'+'a'+'m'='BEAM'
(Other definitions for beam that I've seen before include "XWD SETTER" , "Smile, transmit (radio signal)" , "Smile brightly - supporting timber" , "one gets from the Sun" , "Ray; piece of timber" .)