Sea Tel 9797A-27, Installation And Operation Manual

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Basic System Information 9797A-27 C-Band TXRX
3-4
The Series 97 antennas are 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 the
satellite while the boat turns, rolls or pitches under it. To accomplish this, the
P edestal C ontrol U nit (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.
3.2.6. Search Pattern
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 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.
3.2.7. Tracking Receiver – Single Channel Per Carrier Receiver
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).
3.2.8. Tracking
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
make minor pointing corrections to keep the signal level “peaked” as part of normal operation.
3.3. Components of the System Configuration