This could be quite simple if you have easy safe access to the roof. I would use the RCA model# ANT751 from
www.solidsignals.com . This is an antenna that will bring in all of the stations to your South.
Mount it on the satellite pole turn it to the magnetic location for the channels as per the TV FOOL report, and use the in place cable. You need to replace any splitters that are in your satellite system. locate and replace with splitters designed for DTV. You should be grounded, but if thats not practical, at least use power strips at your sets that have a ground fault loop for your cable. available at any Lowes ect. Just connect to your sets and scan for DTV stations....NOT CABLE CHANNELS. If you are not comfortable on the roof DON'T DO IT! Otherwise full speed ahead.
Good luck!