the recommended proximity si 2-3 meters from the AP. That is, when the AP is yours. If it's not, the recommended proximity is a window with bars and a few cellmates waiting for you to bend over... and hack Your AP.
Just to let you know, the law is clear on accessing another's computer system illegally - and you CAN get in jail for that. If somebody knows you're doing this, and the law enforcement wants to track you down, they will and you will get caught.