Research Concepts RC2500 - Manual (Page 50)

RC2500 Antenna Controller Chapter 5 Modes 43
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5.4.2 STEP TRACK Sub-mode
When the STEP track sub-mode is active, the following actions can occur:
1. The antenna is periodically jogged in elevation and then in azimuth to peak-up the received signal
strength.
2. The controller compiles the track table.
3. Control will transfer to the PROGRAM track sub-mode if the sidereal time advances to a value for
which track table information is available.
4. If the signal strength indicates that the transponder has powered down, the controller will wait a short
while for the transponder to come back online before activating the SEARCH sub-mode.
5. The TRACK MENU system may be used to immediately trigger a peaking operation. See section 5.4.5
for a description of the TRACK MENU system. A more detailed description of the STEP track algorithm is
given in section 4.2.1.
When the STEP sub-mode is active, the following messages may be displayed:
STEP SIG OK IDLE - The AGC input indicates that a satellite signal is present and the controller is
waiting to perform another peaking operation.
STEP SIG OK PEAKING - The controller is jogging the antenna to find the maximum signal strength. The
step size is determined by the Max Track Error CONFIG Mode item, the antenna size, and the frequency
band.
STEP NO SIG IDLE - The AGC input indicates that a satellite signal is not present (the AGC level is
below the appropriate threshold level). The controller will wait approximately 5 minutes for the AGC to
return before activating the SEARCH sub-mode.
5 . 4.3 PROGRAM TRACK Sub-mode
In the PROGRAM track sub-mode, the controller positions the antenna based on values stored in the
track table. The controller will also periodically perform a peaking operation similar to that which occurs
in the STEP track sub-mode. If the difference between the peakup position and the position stored in the
track table is greater than the error specified by the Max Track Error CONFIG mode item, the update flag
for each track table entry is set. When a receiver AGC signal is present and the sidereal time is equal to
that associated with a track table entry whose update flag is reset, a peakup occurs, the peakup azimuth
and elevation position count values are placed in the track table, and the update flag for that track table
entry is reset.
When the PROGRAM track sub-mode is active, control can switch to either the STEP track or SEARCH
sub-modes when the sidereal time advances to a value for which track table data is not available. When
this occurs, the STEP track sub-mode will activate if a receiver AGC signal is available, otherwise, control
will transfer to the SEARCH sub-mode. A more detailed description of the PROGRAM track sub-mode
may be found in section 4.2.2.
The TRACK MENU system may be used to immediately trigger a reposition of the antenna to the azimuth
and elevation position derived from the track table, and to view the contents of the track table. The
TRACK MENU system also allows the user to specify the time interval between peakup operations which
check the accuracy of the data in the track table. Additionally, the TRACK MENU system allows the user
to clear the track table. The menu system is described in section 5.4.5.
When the PROGRAM sub-mode is active the following messages may be displayed:
PROGRAM IDLE - The PROGRAM track sub-mode is active. The controller is waiting to reposition the
antenna.
PROGRAM REPOSITION - The controller has determined that the antenna pointing error is greater than
that specified by the max track error parameter, and is currently repositioning the antenna to a position
derived from the track table.