Tracking Problems - RESEARCH CONCEPTS RC2000C Manual

RC2000C Polar Tracking Antenna Controller
9. 'INITIAL TRACK POL (H OR V)?' Press the appropriate key for the polarization of the initial track.
10. Control will transfer to TRACK mode. 'TRAK' will be displayed in the upper right hand corner of the
display. If the user designated a hybrid satellite (both C and Ku band), the following prompt appears:
'BAND? 0-C 1-K:'. Select the appropriate band for the receiver transponder you wish to initiate the
TRACK function for. The band designation for a hybrid satellite may be changed via the TRACK
menu. The band which the controller assumes is active is displayed in the upper right hand corner of
the display just to the right of the 'TRAK' banner.
11. 'INITIALIZING - PLEASE WAIT' will appear, then the controller will switch to STEP TRACK sub-
mode. The controller will STEP TRACK for 23 hours, 56 minutes, and 4 seconds while building up
the program track table. When program track data is available for the current sidereal time, control
will transfer to the PROGRAM TRACK sub-mode. If the satellite transponder goes down while step
tracking, the controller will switch to SEARCH mode and attempt to reaquire the satellite.
12. A number of errors can be detected during the TRACK mode initialization process. The SCALE
FACTOR error indicates that the Azim Constant CONFIG mode item is set to zero, and two
geostationary satellites with sufficient spacing are not available which allow the azimuth scale factor
to be derived. The SYSTEM error indicates that an alarm message is flashing on the bottom row of
the display. The GEO error indicates that the Geo Elevation Position CONFIG mode item has a
value of zero.
13. If the Search Enable CONFIG mode item is enabled, a good test of the tracking system is to exit
TRACK mode by depressing the MODE key, and selecting the satellite via AUTO mode to reaquire
the satellite. AUTO mode will prompt for the desired polarization and transfer control to the SEARCH
sub-mode of TRACK mode. A search will be performed and when the satellite is found, STEP
tracking will resume.
Please review the description of TRACK mode in chapter 5 for a complete explanation of each of the
TRACK mode submodes and the TRACK mode menu system. Every field of every display screen is
described in that section.
4.4.5

Tracking Problems

This section discusses problems which can occur while tracking an inclined orbit satellite. TRACK mode
contains an ERROR submode, which displays an error message when it is active. Chapter 7 discusses
all of the possible errors which can occur. This section discusses the more common problems.
The LIMIT error occurs when an antenna limit (either azimuth or elevation) is encountered when tracking
an inclined orbit satellite. This error will only occur while the STEP TRACK or PROGRAM TRACK
submodes are active. The SEARCH submode will not attempt to move outside of the azimuth or
elevation limits. This error generally means that the azimuth or elevation (usually elevation) limits are not
set wide enough.
A PEAK LIMIT error indicates that the controller had to move the antenna too far during a STEP TRACK
peaking operation. The maximum movement of the antenna from the starting position for a STEP
TRACK operation is limited. This is to prevent the antenna from peaking up on an adjacent satellite. This
problem can be caused by a number of situations:
1. Specifying too large of an antenna diameter, or specifying Ku band when tracking a C band satellite.
These cause the controller to calculate too narrow of an antenna beamwidth. This beamwidth is
used to determine the maximum allowable movement from the starting position for a STEP TRACK
operation.
2. Specifying too small of a satellite inclination. In STEP TRACK mode, the controller performs peakups
often enough to avoid exceeding the maximum antenna pointing error specified by the Max Track
Error CONFIG mode item. If the specified satellite inclination is too small, the peakups will not occur
often enough, and the antenna may move far enough during a peakup to trigger the PEAK LIMIT
error.
3. The C Band AGC Threshold or the K/L Band AGC Threshold is set too low. If the threshold values
are set too low, when the transponder powers down, the AGC signal of the receiver may be above
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Chapter 4 Inclined Orbit Satellites
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