A lot of people have asked about these as some USB TV tuners don't come with one in the box...
Pigtails with MCX (For Digital TV Tuners) (http://www.rfshop.com.au/Products/Hardware/tabid/426/List/1/CategoryID/872/Category2ID/874/Level/2/Default.aspx)
Suitable for Elgato Diversity and Miglia TV Mini (although the TV Mini comes with one in the box).
We've bought a few cables from these guys in the past and they've been great.