snooper DB8500

Hi all…
Been trying to find a connector which goes into the back of the snooper db8500 for the tv tuner but having no luck
I want to fix the snooper tv outlet onto a normal coax cable onto my ariel on the roof as sometimes when I park up for the night I am struggling for a channel sometimes none at all… :frowning:
any body out there done this already any help would be much appreciated… :smiley: