A coax cable is a coax cable. Just look at both ends of your current one (Horizon end is male push, socket end depends on your socket/adapter) and get a longer one 🙂
Or you could buy another cable that connects to the end of your current one and extends it.
Easiest way is to take your current cable (with any adapters on the socket end) to a UPC shop and ask for a longer one or extension. In my experience of the Basel shop they give cables/adapters for free.