RESEARCH CONCEPTS RC2000C Manual page 22

16 RC2000C Polar Tracking Antenna Controller
Note that the inclination of the orbital plane of an inclined orbit satellites increases at the rate of 0.9
degrees per year (referenced to the center of the earth).
For a polar mount, elevation angle adjustment is achieved by either motorizing the polar mount's latitude
angle adjustment or the polar mount's declination angle adjustment. The latitude angle is so named
because the nominal value of this angle is equal to the antenna's latitude. The RC2000C POLAR
antenna controller can be configured to work with either type of polar mount. The user can specify which
adjustment on the polar mount is motorized via the Mount Type CONFIG mode item. The polar mount
setup procedure differs for each type of mount. Please refer to figure 3.5 for an illustration of declination
angle and latitude angle.
3.4.2.1 Polar Mount with Motorized Declination Adjustment setup Procedure
When a polar mount with motorized declination angle adjustment is setup properly the motion of the
inclined orbit satellite (long axis of the figure eight) is almost perfectly aligned with the movement of the
antenna which results from changing the antenna's declination angle.
Here is the recommended procedure for adjusting the antenna so that the range of elevation movement is
symmetrical above and below the Clarke Belt.
i) Adjust the mount's latitude angle (typically with a threaded rod) to the
antenna latitude. Measure the angle such that if the latitude were 90
degrees the antenna would point parallel to the surface of the earth.
ii) Determine the likely range of the elevation actuator's travel. One limit
of the actuator's range of movement is typically the fully retracted
position - most actuators have a limit switch which activates at the fully
retracted position. The limit switch which activates when the actuator
is extended is typically adjustable. Once the actuator's likely range of
movement has been determined adjust the actuator to the midpoint of
that travel.
iii) Slide the actuator through the clamp until the declination angle is
correct. Measure the declination angle by taking the difference between
the latitude angle and the back of the antenna.
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas 66218-9680 • USA www.researchconcepts.com
Figure 3.5 POLAR MOUNT GEOMETRY
Chapter 3 Installation/Setup