Murdoch's network starts televising rubbish dance (7)
I believe the answer is:
foxtrot
'dance' is the definition.
(I know that foxtrot is a type of ballroom dancing)
'murdoch's network starts televising rubbish' is the wordplay.
'murdoch's network' becomes 'Fox'.
'starts' says to take the initial letters.
'rubbish' becomes 'rot' (both can mean nonsense).
The first letter of 'televising' is 't'.
'fox'+'t'+'rot'='FOXTROT'
(Other definitions for foxtrot that I've seen before include "Lively ballroom dance" , "Ballroom dance in quadruple time" .)