Don’t be so fast as to say electronic signals can’t screw up an old fashioned magnetic compass. We used to sail with friends on Chesapeak Bay. We would regularly include a stop in Annapolis. Just as you round the point of the Naval Academy and turn to sail into the harbor you pass 3 ULF antennas. They are reputed to be part of the Navy’s secret comma system with submerged “Boomers” and other subs.


As you reach the vicinity of the point/ antenna, the magnetic compass , mounted on the steering stanchion, would go nuts . It spun like a top. It happened every time , over a number of years, albeit the ULF system was locally understood to have then been on standby mode , to be used only in an emergency failure of new primary systems in other locations.