Data Hacking

76 Part I — Hardware Hacks
low profile, so they can be left attached and will withstand normal driving speeds and
high winds. For a permanent antenna, you should take the cable into the vehicle through
a hole near the antenna. For a temporary job, it’s a better idea to take the cable in through
the door frame. There is usually enough give in the rubber seal, and as long as you don’t
route it at the top of the door, it is unlikely to let in water.
Consider where you are going to place the reradiator. The usual place for this is on the
front windshield, attached using the suction cups that are supplied with most reradiating
antenna units.
After you have answered the preceding questions, you can set up the reradiating gear:
1. Place the antenna in a suitable spot. Whether you plan to fix the antenna permanently or
temporarily, attach it temporarily initially so that you can test the location before drilling
holes in the bodywork.
2. Route the cable. The passenger door is the typical route into the vehicle (unless you are
planning on a permanent connection — but even then, don’t drill the holes just yet!).
Tape can be used to fix the cables and keep them in place, as can cable ties. Don’t use
wire — this can cut through the cable. Route the cable from the antenna to the location
you have chosen for the reradiator (on the front window).
3. Sort out the power. Route the wiring to the spot where you plan on putting the
reradiator.
4. Add the reradiator. Attach this securely using the suction cups and loop any remaining
cables tidily to keep them under control.
Testing the System
Now it’s time for a test drive with the GPS system running. This can be a simple test in which
you drive around and examine your route afterwards or you can plot a few different routes and
see if the GPS will take you there.
Also test the reception from the reradiator at various points in the vehicle. Remember that
the signal from the reradiator is the same frequency as the signal from the GPS satellites
(just brought a lot closer) so obstructions, especially people, can adversely affect the signal.
If you find that the placement is less than ideal, try raising it higher.
If you have installed a temporary reradiating antenna system, you are not done. After your first
drive around, you might decide that you want to make a few adjustments to the setup (moving
the antenna or rerouting the cables differently).
Making the System Permanent
Now’s the time to make the setup permanent (if that was what you had planned in the first
place). Ensure that you’re happy with the placement of the various antennas and cabling, and
think about any changes or additions you might want to make to your vehicle in the near future
that might mean undoing any work you do now. Moving something held in place with a suction
cup is one thing; moving something after you have drilled holes for it is another.