Through the program, participants receive a battery-operated bracelet — which resembles a wristwatch — that emits a tracking signal every second, 24 hours a day. Each bracelet has a unique ...

You can even try to jam an ultrasonic tracking signal with other ultrasonic sounds, but that will drive the pets in and around your home insane since the ultrasonic sound is audible to them.

June 15, 2005 The Global Positioning System is one of the wonders of the modern world. GPS has been available now in one form or another since 1978 and the full 24-satellite system was completed ...