Inclined Orbit Satellite Setup Checklist - RESEARCH CONCEPTS RC2000C Manual

40 RC2000C Polar Tracking Antenna Controller
the threshold when the antenna is looking at noise. In this case the controller would mistakenly
assume that the satellite signal is present, and attempt to peak up on the noise.
4. If the error occurs during a peakup operation while the PROGRAM TRACK sub-mode is active, it may
be that the Update Check Interval TRACK mode MENU item is set too large.
5. Play or looseness in the mount can cause many problems. The user can test for play by shaking the
antenna. Another test is to see if the antenna peaks on a satellite at different count values depending
on which way the antenna approached the satellite. Here's an example. In one case the peak is
approached by jogging the antenna up and the peak occurs at 110 counts. In another case the peak
is approached by jogging the antenna down and the peak occurs at 103 counts. This indicates that
there are 7 counts of play in the system. The solution is to get rid of the play. In some cases,
increasing the Max Track Error parameter can help. In general, however, the controller is not very
tolerant of looseness in the mount.
If a linear actuator is used to drive the antenna about an axis, it usually forms one side of a triangle. As
the length of the linear actuator changes, the opposite angle varies and the pointing angle of the antenna
is changed. If the linear actuator has some play in it, the change in the antenna pointing angle due to the
play in the actuator can be minimized if the other sides of the triangle are made longer. In some cases,
the ball pivot often found on one side of the linear actuator is also loose. Anything which can be done to
tighten up the ball pivot will help.
It is usually best to choose an antenna mount which uses longer linear actuators, because the 'sides of
the triangle' formed by the mount and the linear actuator are longer. With longer sides of the triangle,
looseness in the linear actuator translates into smaller antenna pointing angle variation.
See section 7.3 - Troubleshooting for more track related errors.
4.5

Inclined Orbit Satellite Setup Checklist

1. Connect the AGC output from the satellite receiver to one of the controller AGC input channels.
Determine the AGC Polarity. Enter the polarity into the controller via CONFIG mode.
2. Adjust the GAIN and OFFSET pots for the selected AGC channel so that when the antenna is aligned
with a strong satellite the signal strength level is around 650, and when the antenna is well off of any
satellite the signal strength level is around 75.
3. Determine the values for the AGC C Band Threshold and/or the AGC K/L Band Threshold, depending
on which frequency bands are used. The threshold values are used to determine whether or not a
satellite signal is present.
4. With the antenna positioned well away from any satellite, tune the satellite receiver across all
transponders to verify that the noise floor is below the threshold.
5. Determine the elevation scale factor. Determine the number of 'position counts per degree' and
multiply this value by 57.29 to get the value for the Elev Constant CONFIG mode item. Note that the
RC2000 counts both the rising and falling edges of each position pulse.
6. With the antenna aligned with a strong satellite tune the satellite receiver across all bands, and verify
that the signal strength level does not reach saturation and remains above the threshold.
7. Enter in the data for the following via CONFIG mode: Antenna Latitude and Longitude, the Time and
Date, and the Antenna Size (in centimeters). Note - once the time is set and the controller is tracking,
do not change the time (i.e. Standard to Daylight savings) as this will invalidate the data in the track
table.
8. Go to setup mode and program in an inclined orbit satellite. As a test of the search algorithm, the
user can go to AUTO mode and select the inclined orbit satellite from the list of satellites programmed
into non-volatile memory. The controller should then perform a search. When the search is
complete, if the satellite is found, step tracking will resume.
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas 66218-9680 • USA www.researchconcepts.com
Chapter 4 Inclined Orbit Satellite