Many years ago while passing a nearby (1/2 mile away) communications tower with loads of antennas on it, my old detector used to go off (can't remember the band) every time I drove up the road and the tower was in sight. This is "cranberry country" - a wide expanse of cranberry bogs with no commercial or private buildings for a mile or more in any direction. This same tower is next to a highway and going down it, the detector also goes off passing within a 1/4 mile. The next time I get in the area I'll note the band the detector is alerting to but for curiosity, what could be radiating from the tower that causes a detector to alarm?
I'm thinking a security motion detector used around the tower site because the tower is in a fairly remote area? I never hear the detector go off going by other comm towers in the region but this one has been triggering my detectors for many years.