>Anybody ever seen one of the "sensors mounted on telephone poles?"<
A former military communications man told me of the type of sensor he
worked with. It had an inverted glass bowl, about a foot in diameter and a
foot tall. Flash and EMP detectors were combined in this unit.
His site once had a bit of excitement when someone keyed a UHF transmitter
whose antenna was about 10 feet from a sensor. Alarms when off and
automatic blast doors slammed shut. The sensor was examined and found to
have a flash detector which failed "on", so all that was needed to
activiate it was the strong RF field from the radio.