With my local 2.4 GHz WLAN I don't have line of sight on either link. There is a "Fresnel region" around the line of sight which must be clear for best transmission. This is about 3 m across for my 150 m path lengths at 2.4 GHz. With 11 dBA antennae I get a reliable, if not good, signal strength with about 50% of this region obscured with trees. K.