L5 sets off store security sensors?

[W8TVI]

When I go to our local library, if I carry the right combo of gear with me I can set off their gates.
When I go there I normally have my laptop backpack with all its gear (power supply, several cat5 cables, etc) and my Zaurus PDA with its wireless card. If I take out one piece gear, the gates won't go off.

Noel

 

[Bravo25]

I can offer this much, these alarms don't work off from metal content. They actually work on a principle that involves a coil of wire. If you have something with a certain coil, wire wrap, or electronic resemblance it will trigger the sensor.

 

[stump]

My wife has titanium knee-joints. She triggers the alarm entering and exiting from Walmart, Best Buy, and Compusa. If they've been recently calibrated, no sweat, but after a week, or so, she sets them off, again.

 

[haertig]

I just went to an AV's hockey game last week when we were on that orange alert. Increased security had them wanding us all down with those handheld metal detectors. I walked right on through with no indications of metal (or whatever they scan for) on me. I was carrying (1) ARC aaa, (2) CMG Infinity, (3) Leatherman Wave, (4) Kershaw Vapor (all metal knife), (5) CRTK PECK (another all metal knife), (6) keyring with 5 keys on it, (7) cellphone, and (8) car door remote control thingy. My wife got through just fine too, despite a keyring that would make a building custodian envious, and (gasp!) a pair of nail clippers!

I wouldn't have expected every one of those items to set off their detectors, but you'd think the combination might have triggered something. So much for enhanced security. I probably could have carried my car in there too!

[edit]
Oh, and speaking of my car (it's really a full size van conversion) ... we went out to the airport during that orange alert too. They were stopping and checking each vehicle. They just walked around the outside of the van looking in each window. Not until we have parked ourselves in the garage did we notice that all the shades were drawn on the windows ... meaning these security guys weren't able to see anything but nice gray pleated shades when they looked in. Oh well!
[/edit]

 

[residue]

are these sensors directional? i still can't figure out why the l5 would trigger an alarm walking into a store but not going out.

 

[Bravo25]

To some extent yes. I even if you walk through with a mechandise sensor at just the angle it wouldn't set off the alarm. If it happens the same way everytime, the sensing electronics are out of adjustment.