What sort of antenna works best for wardriving?
You want some sort of omnidirectional vertical antenna, ideally one that can be mounted on the roof of your vehicle. Again, an external antenna is optional: You can wardrive with no better antenna than the one on the end of your Wi-Fi PC card. Such antennas are poor to begin with, and when they’re inside the vehicle the metal structure of the vehicle shields them from AP signals to some extent. You will gather a lot more stations using an external antenna. In my own tests, a roof mounted omni antenna increases the numbers of stations sensed by at least 50%, and in some cases 100%, over a PC card’s built-in antenna. The antenna I use is quite popular: FAB Corp’s 5 dBi omnidirectional mag-mount, shown at left. The assembly rests on a magnetic disk that sticks to the (metallic) roof of your vehicle, with a length of low-loss coax to take signal to your WI-Fi adapter inside the car. FAB has the same antenna on an NMO connector, in case you’re willing to drill the roof of your vehicle for a
