There is a new device which seems like it might be useful in a beacon position finding system. Their site doesn't have anything much yet, but here is the text from
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"Never lose your keys, or anything else, again. Attach the Loc8tor's
20-mm-long tracking beacons to anything you desire - a cell phone, a TV remote, or even a kid. The handheld device uses radio signals to detect the tagged object's direction and distance from you: It's accurate to an inch, up to 500 feet away. Or use the system's perimeter mode, which alerts you when a beacon leaves your vicinity. Of course, lose the handheld itself and you're pretty much out of luck, buddy. Loc8tor Plus: $170,
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"
And I think they should have spelled it Loc8or.
Mitch