

Tracking Device Teardown - aburan28
https://www.ifixit.com/Teardown/Tracking+Device+Teardown/5250

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Fizzadar
As well as the teardown, the disclaimer is pretty interesting too:

> We love the FBI. We've worked with them on several occasions to fight crime
> and locate criminals. We've helped them with instructions on gaining entry
> into certain devices. We have nothing against them, and we hope they don't
> come after us for publishing this teardown.

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mmastrac
This doesn't have a date on it, but the corresponding blog post suggests 2011:
[http://www.ifixit.com/blog/2011/05/09/fbi-tracking-device-
te...](http://www.ifixit.com/blog/2011/05/09/fbi-tracking-device-teardown/)

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rocketeerbkw
The accompanying wired article
([http://www.wired.com/2011/05/gps/](http://www.wired.com/2011/05/gps/)) was
published May 2011, says the device was found in 2005, and the teardown
suggests parts were as old as 1999.

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quadrature
Anyone else wondering where all the transponders are located ?. I would have
expected a tracker to piggy back on cell towers so that they could use
existing infrastructure but that probably doesn't work from an intelligence
standpoint.

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kw71
It works fine and this is commonly their connectivity arrangement. This one is
remarkable because it has some UHF radio hardware. They don't need to have a
network of transponders: one will work just fine if the victim regularly comes
into its proximity. At those times it can be queried for position information.

~~~
quadrature
What do you think the range on that transmitter would be ?

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kw71
According to the datasheet [1] the transceiver outputs -5dBm. (This is 5dB
less than 1 mW.)

This specific device is not analyzed enough to reveal whether or not there is
an additional amplifier, which "could" be made from a single transistor and
some passives.

Assuming that there is no amplifier, and taking into account the short wire
antenna and detrimental environmental conditions, I feel safe guessing the
upper bound of useful range will not be more than a 250 m distance. Probably
it's half that.

I will also guess that the fixed part (you can call it a transponder or base
station) will not have power budget to worry about so it will periodically be
announcing itself (you don't want the mobile part to do this because it will
consume the battery.) The mobile part will answer when it hears this
transmission. If this is true, then a TSCM beginner will be able to play "find
the beeper" pretty easily.

[1]
[http://www.datasheetarchive.com/dlmain/Datasheets-40/DSA-798...](http://www.datasheetarchive.com/dlmain/Datasheets-40/DSA-798216.pdf)

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xwintermutex
Too bad that there aren't many details on the wireless link (e.g. frequency,
protocol)

