hmm, ill have to double check if my internal can do packet injection. my old laptops internal can. haha i bought that thing back in 06. I will have to check up on these alfa cards you speak off. i like the idea of removable antennas. I build my own parabolic ones that i would love to hook up to my laptop. haha. or better yet, ill make the alfa card, if its usb, the focus of the dish.
The best i have done, i took a usb wifi adapter and hooked it up to my firends 8 foot diameter dish and pointed in in random directions to see what we could find. haha. 65 networks.