Ubiquiti Networks airMA ac Sector Antenna - Manual (Page 9)

9. The antenna has an electrical downtilt of 2°. To further
adjust the elevation angle:
a. Loosen the four Serrated Flange Bolts on the U-Brackets
and the two Serrated Flange Nuts on the upper
Pole Clamp.
b. Slide the antenna to the desired tilt. (The brackets may
slide along the pole, depending on the angle of the
elevation tilt.)
c. Tighten all bolts and nuts to approximately 25 N-m.
Serrated Flange Bolt
Serrated Flange Nut
Serrated Flange Bolt