Edimax Technology 802.11n/MIMO Antenna Relocation Stand EA-MARS - Manual (Page 13)

The antennas on the right and left side are for signal reception and
should be set perpendicular (90 degrees) to each other. The central
one is for signal transmission and should be pulled up about 45
degree. Please see the illustration below.
About antenna angle adjustment
Please position place the antenna vertically to the horizontal
surface (ceiling or floor), since the omni-directional antennas
best signal coverage is 360 . Do not put the antenna
perpendicular to the wall.
12