Bandwidth Speed

Just completed a wireless setup. I am using a hi-gain antenna to see my friend's wireless network. He is about 250 feet from my house. I have an excellent signal strength (80%) and my link quality is 80%. We are using 11Mbps hardware. When I checked my bandwidth speed through his wireless network I am seeing a 1Mbps in speed out of a possible of 2Mbps. He is seeing the normal 2Mbps bandwidth speed with a 95% signal level on his laptop less than 30 feet away in his living room. When he walks toward my home with his laptop both signal level and his bandwidth speed drop, which makes sense I guess since the link quality is also lower. Is what am seeing normal or to be expected with the 250 feet distance from my house to the access point at his house. I expected less bandwidth speed but not half with the excellent signal and quality level that I have with my hi-gain antenna. Does anyone have any experience in this area of wireless networking on this forum? Is this just the way wireless networking is or what?

By the way my friend saw a drop in speed with a drop in signal as he walked toward my house away for the access point at his house, but when I intentionally dropped my signal and link levels to a low reading I still got the 1Mbps. I did this experiment several times so I know it was real. Strange.