Sea Tel DAC-03, Инструкция по установке и эксплуатации

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Basic System Information DAC-03 Tracking Antenna Controller
3-4
3.2.4. Stabilization
The Sea Tel 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), along with multiple sensors mounted 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.
3.2.5. Narrow Band Tracking Receivers
70 MHz or 140 MHz Single Channel Per Carrier (SCPC) Receiver - The Narrow Band SCPC
Receiver located in the Antenna Control Unit (ACU) is used to acquire, identify and track a narrow
band carrier or beacon. When properly setup, the receiver settings are saved to expedite future
acquisition of satellite signal.
When searching for the desired satellite this receiver compares the current receive signal level to
the “Threshold” level. When the received signal level, at the current frequency, exceeds the
threshold value SEARCH will suspend and TRACKING will peak the pointing of the dish to maximize
the receive signal. The system only needs adequate satellite signal level to stop searching and begin
tracking the satellite. This receiver is not able to identify the satellite it is receiving.
3.2.6. Tracking
The ACU 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
The following text provides a basic functional overview of the system components and component
interconnection as referred to in the System Block Diagram for your model antenna.
Television Receive Only (TVRO)
Systems are comprised of two major sections: The Above-Decks
Equipment (ADE) is comprised of the Sea Tel antenna & radome assembly which is mounted outside, on an
upper deck location chosen for best satellite reception. The Below-Decks Equipment (BDE) includes the
Antenna Control Unit and will have satellite receiver(s), TV set(s) and all other ancillary equipment that is
mounted in various locations throughout the interior of the ship.
Transmit/Receive (TXRX) Systems are also comprised of two major sections: The Above-Decks
Equipment (ADE) is comprised of the Sea Tel antenna & radome assembly which is mounted outside, on an
upper deck location chosen for best satellite reception. The Antenna inside the radome has Transmit &
Receive RF equipment mounted on it. The Below-Decks Equipment (BDE) includes the Antenna Control
Unit and will have satellite modem, Multiplexer and all other ancillary communications equipment that is
mounted in various locations throughout the interior of the ship.
3.3.1. Antenna ADE Assembly
Refer to your Antenna manual for specific information about your antenna, radome and
interconnecting cables.
3.3.2. Antenna Control Unit
The Antenna Control Unit allows the operator to control and monitor the antenna pedestal with
dedicated function buttons, LED’s and a 2 line display. The ACU and its Terminal Mounting Strip are
normally mounted in a standard 19” equipment rack. The ACU should be mounted in the front of
the equipment rack where it is easily accessible. The Terminal Mounting Strip and base multiplexer
panel are normally mounted on the rear of the equipment rack. In TVRO systems, it is
recommended that the antenna control panel be mounted near one of the Satellite Receiver
locations where you can see the television screen while you are controlling the antenna.