Recently I had a need to get substantial improvement in my wireless router's performance, and thought a yagi antenna would help. Whoa! It did indeed help, so I have posted some pictures and a short how-to on the web at:It is the same 15 element yagi used for extending the range of USB wireless adapters, but connected via pigtail to a router. I can now connect indoors through concrete and plaster walls or provide wi-fi connectivity to laptop and Ipod touch users up to 300 meters away, in the presence of interference.
Maybe it can help some of you trying to cover some large areas with your routers.