I built a cantenna and it seems to work great but with it I noticed an odd
behaviour with the list of networks Windows sees:
If I point it in a direction and search for wireless networks, get the list,
then set the antenna face down on a sheet of foil to block all signals and
search agaon, it keeps all the networks it found before! Now if I keep the
antenna on the foil, then disable then enable wireless and search, it will
find nothing.
This is annoying because if I point the antenna in another direction, I have
to disable and enable then search to find acess points unique to that
direction.
Why does Windows not dump the previously found network list when searching?
Windows XP wireless network list behaviour 
Linear Mode
