I suggest a
91-XG antenna & your present 8780 preamp since Columbus is now an all UHF market. If you are interested in
WMFD from Mansfield you will need a VHF antenna, but not sure if their programming interests you? The only other possible station outside the Columbus market would be
WHIZ-NBC from Zanesville. (Doesn't seem to offer any HD programming though) You will need a rotator if you would like that alternate NBC affiliate. I'm not sure if the CW affiliate south of Columbus will be gettable 24/7, but the 91XG will give you the best chance of seeing that channel.