Broadcast live in the morning (4)
I believe the answer is:
beam
'broadcast' is the definition.
(beam can mean to broadcast or transmit)
'live in the morning' is the wordplay.
'live' becomes 'be' (synonyms).
'in the morning' becomes 'am' (short for ante meridiem - before noon).
'be'+'am'='BEAM'
(Other definitions for beam that I've seen before include "Smile; piece of timber" , "Ray of light - structural piece of wood" , "Smile radiantly" , "Ship's width; ray" , "Supporting piece of wood - shaft of light" .)