Programming Geostationary Satellites - RESEARCH CONCEPTS RC2000C Manual

20 RC2000C Polar Tracking Antenna Controller Chapter 3 Installation/Setup
elevation position is 30. The user then moves the antenna to a position of 175 and sets the upper limit.
At this point the displayed elevation position is 175. The user then moves the antenna to an elevation
position of 100 and sets the Geo Elevation Position. The displayed elevation position is then 0. After the
Geo Elevation Position has been set, when the antenna is at the down elevation the displayed elevation
position is -70 (30 - 100), and when the antenna is at the up elevation limit the displayed value will be 75
(175 - 100).
When LIMITS MODE is entered, if a non-zero Geo Elevation Position exists, it is temporarily reset to zero
so that the actual elevation position count is displayed. If the user resets the down and up elevation limits
without resetting the Geo Elevation Position, the Geo Elevation Position is permanently reset to zero
when LIMITS mode is exited. If the user exits LIMITS mode without changing the down and up elevation
limits, the Geo Elevation Position which existed on entry is restored.
3.7

Programming Geostationary Satellites

After the limits have been set and the slow speed code determined, geostationary satellites can be
programmed into the controller's memory. Inclined orbit satellites are programmed into memory after
these geostationary satellites are programmed. The programming of inclined orbit satellites is covered in
chapter 4.
All satellites are programmed into memory via SETUP mode. In SETUP mode the user can jog the
antenna in azimuth and elevation to peak up on a satellite, specify the satellite name, and jog the
polarization to assign H and V polarization values. This information is retained in the controller's non-
volatile memory. The user can automatically position the antenna on a satellite which has previously
been programmed into memory by invoking the AUTO mode, and using the SCROLL keys followed by
the ENTER key to select the satellite.
SETUP mode is straightforward. If the user wishes to assign a satellite name which is not in the list, the
USER entry in the satellite name list may be selected. The user is then prompted to enter an
alphanumeric string using the SCROLL UP, SCROLL DOWN, and ENTER keys.
After the satellite name has been specified, the user is prompted with 'IS THIS AN INCLINED ORBIT
SATELLITE (YES/NO) ?". The user responds to this prompt by pressing the SCROLL DN/NO key to
indicate that the satellite being programmed into non-volatile memory is geostationary.
After the inclined orbit satellite prompt, the user is prompted to enter in the satellite's longitude position. If
the satellite name came from the controller's internal list, the user is presented with a longitude value also
from the controller's internal list. The range of longitude values accepted by the controller ranges from 0
to 180 West and 0 to 180 East. Satellites located over North America have West longitude values.
Satellites located over Asia have East longitude values. Some Intelsat literature gives satellite longitude
values in a range of 0 to 359. In this scheme, values from 0 to 180 correspond to East longitudes.
Values from 180 to 359 correspond to West longitudes. To convert from the Intelsat scheme to the
scheme used by the controller, a simple example is presented. If the satellite longitude is specified as
325 degrees in the Intelsat scheme, to convert to the value needed for entry into the controller, calculate
360 - 325 (= 35). The value entered into the controller would then be 35.0 West.
The user is next prompted to specify the horizontal (H) and vertical (V) polarization values for the satellite.
The user must do this even if the antenna does not have a polarization skew adjustment.
If polarization adjustment is not available for a given installation, the Rotating Feed Present CONFIG
mode item should be set to NO. When the Rotating Feed Present CONFIG mode item is set to NO, the
controller assumes that a polarotor is present in the system. The RC2000 controls the polarotor in an
open loop fashion, i.e., the RC2000 cannot detect whether or not a polarotor is actually present.
To specify the H polarization, the user should use the CW and CCW keys to adjust the polarization on a
horizontal transponder to the desired value, and then hit the H key. To specify the V polarization, change
the receiver to a vertical transponder, and use the CW and CCW keys to adjust the skew and then hit the
V key. BOTH polarizations must be set.
It is recommended that the user first program in a pair of geostationary satellites, and then use the AUTO
mode to repeatedly position the antenna on one satellite and then the other. This will exercise the
controller, actuators, mount, and position sensors. If the antenna does not return to the peak for each
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