> You can do what your trying to do but you might have to > create some of your own code. For true directional finding (DF'ing) > you would need a reciever and a doppler DF system that can recieve at > 2.4ghz (aka the wireless card for the reciever). Netstumbler allows > you to view client accesses. With the bearing information you obtain > from the doppler DF system, you can then use the GPS coordinates you > acquired while receiving the signal to triangulate the intruder. This > would have to be intergrated into one system (aka linux) if you ask me > to be in some sort of real-time fashion. > > Example Doppler http://www.silcom.com/~pelican2/MINI_CIRCUIT.html
I always understood that doppler only works with narrowband signals. For broadband you need to use a directional antenna, or compare time-of-flight data from three or more base stations. The timing differences in time-of-flight are very small so I wouldn't expect to be able to do this without some serious additional hardware. The long term solution is to make a whitelist of allowed mac addresses, and simply ignore all other traffic. Or firewall off everything but PPTP traffic and use an encrypted VPN. If you really must 'track them down', get a directional antenna and a laptop with the appropriate hardware and software to show signal strength from the target machine, and go for a walk. While you're out walking have a think about what you're going to do when you find them, and if you feel like doing this several times a week as wireless hardware gets more popular.
