I have one of those vehicle loop detectors installed on my property. Same kind that operate traffic lights.
To test it (and the stuff I've added like lighting and alarms) I put a2'X2' piece of sheet metal on the loop. That's unwieldy and a pain because I have to store it some distance from the loop.
So I got a detector and wired up a 4" dia loop ~30 T for ~80 uhy, or what the 12' loop with 3T should produce.
Works like a champ, but ferrite makes it go crazy (loop detects the ferrite leaving the loop one time, and then detects it entering from then on) - there's a microprocessor involved in the innards of the commercial loop detector.
Then I tried a shorted turn and that seems to work on the 4" loop but not even a 4' diameter shorted turn will trigger the 12' loop. Yet a1" diameter shorted turn will trigger the 4" loop.
Small, very powerful magnets - nada. It won't see them.
So far it looks like a piece of chicken wire fencing ~2'X4' is the best I've been able to do. Triggers the loop and is not so much hassle to carry around so I can make a dummy "target" and leave it out by the loop without it looking like roadside trash. (so the city doesn't get pissed off)
Anyone with some ideas on how to trigger traffic loop detectors? (and I ride a motorcycle too, so this ain't just an exercise in logic)