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I am not into all the tech details of communication via RF with implant chips (tracking chips) and so would like to ask how the known atmospheric pertubations of shortwave radio affect the distances over which one can closely and continuously track an animal with an implanted chip (e.g. a chip transmitting physiological information).

Thanks in advance !

J

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-in ref. to e.g. RFID tags. I am also thinking in regard to e.g. the scenario proposed by Lawrence Kates United States Patent number: 7634975 (RFID tracking of dogs with methods to induce pain or pleasant vibrations to punish or reward in order to control their behaviour Issue date: Dec 22, 2009 - This method could be used by animal abusers - would there be anyway to prevent such? –  J Thorsdatter Sep 16 '11 at 15:53
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I think you are confusing a few different technologies.

GPS only receives signals from the GPS satellites, for this it just needs an external antennae. It isn't going to work with an implanted device in a dog.

Radio directional finding (RDF) transmitters used to track migrating animals broadcast a continuous signal which is followed by simply looking for the direction that the signal is strongest and assuming the animal is in that direction. Again you need an external antenna and more power than GPS (modern tag systems actually find the animals position by GPS and broadcast it by cell phone)

RFID comes in two types, powered and unpowered. If the tag has power it can broadcast a stronger signal or use a smaller antennae and work over 10s of meters. An unpowered RFID tag - like the tags used to 'chip' pets uses power broadcast from the reader and only work over a few cm.

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and just for the record, a GPS device can be located anywhere in the world; you might have seen the android version where u can get your friends' location. Where an RFID has serious limitations in terms of range. –  Vineet Menon Oct 17 '11 at 4:50
    
@ Vineet Menon - Whilst a GPS device can locate itself anywhere in the world, the device cannot necessarily be located by a third party unless it actually transmits its position by radio or over a communication network, which will necessarily have variable range and coverage. GPS devices only calculate their position via the GPS satellites, they don't transmit to them. –  Richard Terrett Oct 17 '11 at 8:00
    
precisely, the device should send its location information voluntarily as in an android(phone) over another channel different from the one used by GPS. –  Vineet Menon Oct 17 '11 at 11:44
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