Research Concepts RC2000A - Manual (Page 29)

RC2000A Dual Axis Antenna Controller Chapter 3 Installation/Setup 29
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 UP and SCROLL
DOWN 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 selected the user is prompted to enter in the satellite's longitude
position. If the satellite name came from the controllers 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 also has an option in specifying the H/V polarization data. After at least one satellite has been
programmed into non-volatile memory, the user can specify that the horizontal and vertical position data
for a satellite which is about to be entered into non-volatile memory can be copied from the satellite in
non-volatile memory closest to the antenna's present position. With an elevation over azimuth type
mount, however, it is recommended that the user always manually peak up the H and V polarization
values for each satellite.
If a modified polar antenna mount is used (see section 3.4.3 - Geo Elevation Position for a discussion of
modified polar mounts) the option of using H/V data from the nearest satellite may be a time saver. For
C band satellites H and V polarities are well coordinated from one satellite to the next (i.e. the H
polarization position for Galaxy 5 are nearly the same as the H polarization position for Galaxy 6 - both
are C band satellites). For Ku band satellites, however, the H and V polarities are not well coordinated
from one satellite to the next. Using the 'H/V polarization data from the nearest satellite' option should
be selected only for the case where the user is using a modified polar mount in a C band only system.
It is recommended that the user first program in a pair of 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 RC2000A antenna controller has the capability to display it's azimuth and elevation position in an
angle format. This capability can facilitate the process of locating satellites during system setup for
systems that employ an elevation over azimuth type of antenna mount. 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
included with the controller.
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 scale2.exe program on the floppy disk can be
used to determine these parameters once a pair of satellites has been found.
Another program included on the floppy disk is antenna.exe. This is a general purpose program which
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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