Programming Geostationary Satellites; Angle Display Of Az/El Position Data - RESEARCH CONCEPTS RC2000C Manual

18 RC2000C Az/El Tracking Antenna Controller Chapter 3 Installation/Setup
3.6

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
the geostationary satellites are programmed (described in Chapter 4). The user should review this
section along with the following section before programming in any satellites. The following section
discusses the display of azimuth and elevation position data in an angle format, and explains the use of
the IBM PC programs found on the disk included with the controller. Displaying the azimuth and
elevation position in an angle format can be a great aid in locating satellites. Note that it is not
necessary to program any geostationary satellites into memory before initiating a track on an inclined
orbit satellite.
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 (on those controllers which support polarization
control). 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 that 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 selected 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.
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 satellite make sure that the position sensors are properly wired. After the operation of the system
has been verified by testing with two geostationary satellites, the rest of the satellites may be
programmed in.
3.7

Angle Display of Az/El Position Data

The RC2000C antenna controller has the capability to display its azimuth and elevation position in an
angle format. This capability can facilitate the process of locating satellites during system setup. This
section describes the procedure for enabling, calibrating, and using the angle display feature. The
procedure outlined in this section makes use of the programs (designed to run on an IBM compatible
PC) found on the floppy disk in the back of this manual.
The controller can display azimuth and elevation position in a degrees format. When this feature is
enabled, the azimuth position is displayed as a true heading (in degrees - 0 to 360) and the elevation
position is displayed as an angle above the horizon (0 to 90 degrees). This feature is controlled by
parameters specified by the user via CONFIG mode. The scale3.exe program on the floppy disk can be
used to determine these parameters once a pair of geostationary satellites has been found.
Another program included on the floppy disk is antenna.exe. This is a general purpose program that
aids the user in locating any satellite. This program prompts the user to enter the antenna longitude
and latitude, the satellite longitude and the satellite inclination angle and calculates the magnetic
heading, true heading and elevation angle above the horizon needed to intercept the satellite. For
geostationary satellites, the satellite inclination angle is 0.
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