Station has broadcast on low (3,4)
I believe the answer is:
air base
'station' is the definition.
(station for aircraft)
'broadcast on low' is the wordplay.
'broadcast' becomes 'air' (to air on TV).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'low' becomes 'base' (synonyms).
'air'+'base'='AIR-BASE'
'has' acts as a link.
(Other definitions for air base that I've seen before include "From which military planes fly" , "Station for military aircraft" , "military installation" , "Flying station" .)