We looked at a wifi honeypot a while back. Maybe it is time to look at wifi antennas also. As with HDTV antennas, there are quite a few examples of the DIY types. There are two types of wifi antennas. The are directional antennas and the omni-directional antennas. Omni-directional antennas try to capture wifi radio waves from all directions. Sort of a generic antenna. Where as directional antennas capture wifi radio waves from a specific point or direction. Directional antennas can focus on another wifi access point quite a bit bettter than the omni-directional antenna. Wifi radar software can take extreme advantage of a directional antenna. More about that later.
We made a directional wifi antenna out of a one dollar plastic salad bowl (surrounded in foil) and holding the usb wifi unit.
Antenna hacks people have done:
PLEASE USE THESE FOR ETHICAL USES ONLY!!
Software: (Sites have detailed instructions.)