If you try the cheapy method, not just any balun works. If you sort through your drawer of these things you need one that is isolating, i.e. it should exhibit a couple of mega-ohms between the connectors. You need a volt-ohm meter to sort them out. Most are only 50 ohms or less, and will not work.

Check out
www.smr-home-theatre.org/Ground-Loops