I am getting hum from my amp now that my DSS is installed. Here is my setup: Dish on roof--dish itself is not grounded. Coax run about 40' to get closer to main ground rod. Coax plugs into ground block and 12awg solid copper wire goes into main rod. There seems to be 2 other very thick wires connected there as well, but I got it in the clamp along with the other wires. From ground block, my coax goes into attic then down wall to wall plate and into surge protector, then into my Sat receiver. When I turn my receiver pretty high (-25 db) I hear a distinct hum that I NEVER had before. Am I grounded properly? Any ideas?