We partnered with Wired to bring you a peek inside an FBI car-tracking device. The device is similar to the one Yasir Afifi found underneath his car. If you're curious where this one came from, Wired has posted a writeup about Karen Thomas, the woman who found this tracker under her car. They've also posted a video of Kyle doing the teardown.

The device comprises of a GPS unit for receiving the car's position, an RF transmitter for relaying your location to the interested authority (aka the FBI), and a set of sweet D-cell batteries that power the whole enchilada. But we didn't stop there, of course. Read on to find out exactly what components make this secretive device tick.

• We finally have one of these on the teardown table! Being in its presence, we can almost feel our civil liberties being flushed down the toilet.

• Before we whip out the blowtorches and jackhammers, here's a look at the entire tracking system.

• Clockwise from the top, the system consists of:

  • Battery pack

  • GPS antenna

  • Transmitter/receiver unit

  • Magnetic mounting bracket

• The components of the system are all attached to the tracked vehicle with extremely powerful magnets. Some were so stubbornly attached that they ripped out of the mounting brackets to forever remain stuck on the undercarriage of the host vehicle.

• Wondering what kind of technology keeps the tracking device powered? Let's remove the battery pack's end cap and find out.

• The device is powered by four lithium-thionyl chloride (Li-SOCl₂) D cell batteries.

  • Each cell is good for 13,000 mAh! That's about double the capacity of the iPad 2's battery.

• These cells are suited for extremely low-draw applications where longevity is needed, making them ideal for powering an always-on transmitter/receiver. Their service life is rated at 10 to 20 years.

• To begin tearing the device apart, we detached the two antennas from their screw-in mounts on the transmitter/receiver module.

• The short antenna we disconnected in the first picture is responsible for transmitting the location signal to transponders that the FBI would use to find you.

• The larger antenna is for receiving GPS signals from satellites orbiting far above the earth's surface.

• Removing a few Phillips screws allows us to access the innards of the GPS antenna.

• In keeping with the non-permanent mounting solutions, the GPS antenna is attached to its bracket with a hefty piece of Velcro.

• A quick peek at the antenna board indicates it was manufactured by SIgem, a company that partnered with Tyco in the early 2000s to make GPS components.

• Let's turn our attention back to the transmitter/receiver module.

• A few screws are all that remain between us and the innards of this invasive device.

• It seems that this rear cover is simply a method to connect the module to power. Presumably, power sources (batteries) of different shapes/sizes/capacities can be connected through the same plate to make the tracking device more universally installable.

To get to the brains of the module, we focus on the other end cap.

The FBI really did not want anyone tampering with the innards of their tracking devices. The screws were coated with so much threadlocker that we had to break out the power drill and eliminate the screw heads.

• Upon successfully drilling out all the screw heads, the outer case slides right off the transmitter/receiver assembly.

• The two modules can be split apart to examine their circuits.

• The small blue wire connects the GPS antenna to the GPS receiver board.

• After disconnecting the GPS board, we can take a closer look at both components.

• The module providing the GPS signal processing on this device is a µ-blox GPS-MS1 that's sort of ancient in the realm of modern electronics.

  • It was released June 29, 1999!

• It features an astonishing 0.125 MB of SRAM and 1 MB of flash memory.

• The backup battery on its reverse side powers a real time clock and maintains the GPS receiver's SRAM to allow for a much faster connection time to the satellites, called a warm start. This is usually used in conjunction with a circuit to power down most of the GPS, providing a much longer battery life.

• The slightly imperfect alignment of the SMD components on the board indicates that the FBI hand-soldered them to the board and tailored the component choices to their specifications.