Research Concepts RC1500 - Manual (Page 18)

Antenna Setup
RC1500B Quick Start Guide 18
Down Limit
9. In this step we set the ACU’s (antenna control unit’s) Down limit. With the Mount
Hour angle set at zero, the Down limit is set when the antenna’s RF Pointing Angle is
equal to the Base_Elevation Minus 10 Degrees. Base_Elevation was found in step 4.
The Patriot 1.2 and 1.8 meter antennas have a 22.5 degree offset. To achieve an RF
Pointing Angle of Base_Elevation Minus 10 Degrees, the backstructure of the antenna
must be inclined at an angle of Base_Elevation – (22.5 + 10) degrees with respect to
vertical. Figure 20 below shows placement of the inclinometer on the antenna
backstructure.
Example:
Base_Elevation – (22.5 + 10) degrees
44.9 – ( 22.5 + 10)
44.9 – (32.5)
= 12.4 degrees (Down Limit with respect to vertical)
90 – 12.4
= 77.6 degrees (Down limit with respect to horizontal)
Figure 20 – Inclinometer Placement to Set Down Limit