I had the same apparent Ground Loop problem without Buckeye Cable. It seems a majority of technicians have little experience with recognizing and solving apparent group loops. Or perhaps they worry about the costs to eliminate the ground loop.
Search the internet for suggested solutions that are considered safe. Simply running the buckeye cable through a surge protector that includes coax protection may fix it. A coax isolation transformer may be another solution, which you could make by connecting a 75 ohm to 300 ohm transformer to a 300 ohm to 75 ohm transformer.
Ground loops happen for me all the time because I keep adding cameras and other devices to my security system and with cheaper solutions like using old home video cameras it was easier to get ground loops.
