Data Hacking

72 Part I — Hardware Hacks
There are several manufacturers of lightening arrestors. Here are a few to get you started:
Symmetricom: www.symmetricom.com
PolyPhaser: www.polyphaser.com
Radiall: www.radiall.com
LightningMaster: www.lightningmaster.com
This solution may seem pricey for something that may never be needed, but if you live in an
area where lightning is common, consider how much it will cost you if your antenna is hit and
you lose your GPS.
In addition, it’s not just the GPS that you can lose — if your GPS happens to be connected to a
PC at the time of the strike, you could also lose the PC and possibly even others connected on
the same network if you happen to use one.
Other Things to Avoid
Here are a few other things that you should avoid when it comes to using external antennas:
Knots and kinks in cables damage the interior of the coax and can cause signal loss. Keep
the cables as straight as possible, and if the cable does have to travel around corners, don’t
make the loop too tight.
Be careful about bringing cables in through windows and door frames, as crushing can
severely damage the cable.
Another way to damage a cable is to stretch it, so take care to avoid this. If you install the
cable in warm weather, make sure you leave additional slack in the cable, as it will contract
when the temperature drops.
Keep the cable short and reduce the number of connectors: The greater the length of
cable and the more connectors and joints you have in it, the more signal loss you will
experience.
Reradiating Antennas
Another type of antenna you will come across is called the reradiating antenna. This is a combination
GPS antenna and retransmitting unit.
It works as follows:
1. The main antenna picks up the GPS signal just like any other GPS antenna.
2. This signal is fed down a cable to a signal reradiator.
3. The signal reradiator takes the signal and reradiates it. This signal is then picked up by
the antenna on the GPS.