Make use of a screen broadcast (5)
I believe the answer is:
avail
'make use' is the definition.
(I've seen this before)
'a screen broadcast' is the wordplay.
'screen' becomes 'veil' (I've seen this before).
'broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'veil' sounds like 'vail'.
'a'+'vail'='AVAIL'
'of' is the link.
(Other definitions for avail that I've seen before include "Be useful" , "Be of help or advantage" , "Make use, take advantage" , "Be of value to" , "Use to one's advantage" .)