System information

9797B-70 C-Band TXRX Basic System Information
3-3
3.2.3.
If you have a circular polarization feed installed, you do not need to adjust the “polarization” of the antenna.
Antenna polarization
If you have a linear polarization feed installed, the system should have been adjusted properly and set-up to
operate in Auto-Polarization mode. The ACU will then automatically adjust the polarization of the feed as the
ship changes geographic locations.
3.2.4.
Your antenna is stabilized in all three axes of motion. Stabilization is the process of de-coupling the ships’
motion from the antenna. Simply put, this allows the antenna to remain pointed at a point in space while the
boat turns, rolls or pitches under it. To accomplish this, the Pedestal Control Unit (PCU) on the antenna
pedestal assembly senses the motion and applies drive to the appropriate motor(s) in opposition to the
sensed motion. Azimuth (AZ), Elevation (EL) and Cross-Level (left-right tilt) are actively stabilized
automatically by the PCU as part of its normal operation.
Stabilization
3.2.5.
Whenever the desired satellite signal is lost (such as when the antenna is blocked) the Antenna Control Unit
will automatically initiated a Search to re-acquire the desired signal.
Search Pattern
Search is conducted in a two-axis pattern consisting of alternate movements in azimuth and elevation. The
size and direction of the movements are increased and reversed every other time resulting in an expanding
square pattern.
When the antenna is able to re-acquire the desired signal the ACU will automatically stop searching and begin
Tracking the signal to optimize the pointing of the antenna to get the highest signal level from the satellite.
3.2.6.
The SCPC Narrow Band Receiver located in the Antenna Control Unit (ACU) is used to acquire, identify and
track a narrow band carrier, or beacon signal, or the desired satellite. When properly setup, the settings for
the satellite are saved to expedite future acquisition of the desired satellite. The system must have adequate
satellite signal level to stop searching (and begin tracking the acquired satellite).
Tracking Receiver – Single Channel Per Carrier Receiver
3.2.7.
Your Antenna Control Unit actively optimizes the pointing of the dish for maximum signal reception. This
process is called tracking and is accomplished by continuously making small movements of the dish while
monitoring the level of the received signal. Evaluation of this information is used to continuously move the
stabilization point toward peak satellite signal reception. These minor pointing corrections keep the signal
level “peaked” as part of normal operation.
Tracking