Barry, Did you power down devices that have a battery back-up such as alarms, internet cable connection? I always recommend using two Common Mode Chokes, one at the antenna feed-point and the other in the shack. Try disconnecting the wire to the ground rod. Is there another ground wire path in the shack ? I have added CMC torroids on all power line wires in the shack. Especially the on the green safety wire. I also use a TRIPP-Lite Ultra for the shack stuff. The Ultra-6 has 3 RF isolated and filtered paths. Drop me a email (QRZ address) if you want more of my comments. 73 & Be Well,
Joe O, K I 5 F J, NNNN