I am with Minn here. I almost always put my antenna inside the plane. I have never had a range problem with the basic installation. I do try to keep the antenna as straight as possible, and to keep it at least an inch or two away from servo's and other wiring. Also, when I change direction, I try to keep it at least an inch away from itself as well, such as running down one side of the fuse, then when the tail section gets narrow, run straight accross and up the other side of the fuse.

Also, I always do my range checks on the ground and expect at least 100 feet distance without trouble.