Installation of the dual antenna solution
B-2
Appendix B: Dual antenna solution
98-175666-A
In a dual antenna configuration, the inactive (passive) antenna points where the satellite
was found at start-up or where last tracked while the antenna was active. The inactive
(passive) antenna uses the following criteria to dynamically maintain the correct relative
azimuth and elevation irrespective the antenna can receive the satellite signal or not (open
loop algorithm):
1. The NMEA-0183 heading data, which must come from a gyro compass without drift,
deviation, speed or latitude errors.
2. The built-in rate sensors, accelerometers and GNSS receiver.
3. The calculated change in azimuth and elevation of the satellite position (Clarke belt) as
the vessel moves.
Parts needed
The following parts are needed for the SAILOR XTR Ka Dual antenna solution:
• 1 x SAILOR XTR Ka System (Master System)
• 1 x SAILOR XTR Ka ADU (Slave Above Deck Unit)
• 1 x SAILOR XTR Ka BDU (Slave Below Deck Unit)
• 1 x Accessory Kit for Dual Antenna operation
consists of 2 x RF Splitter/Combiner and 2 x Coax cables with F-connectors, RS-422
modem keyline/dual antenna splitter cable (37-179068)
Figure B-1: Dual mode antenna, connection diagram
Important
OPERATION ON INCLINED ORBIT SATELLITES
Dual antenna installations might experience degraded performance when
operated on inclined orbit satellites. These satellites change their position
during the day. The changed satellite position affects the inactive (passive)
antenna, resulting in mis-pointing to the satellite at the time the antenna
becomes active.
ADU (Slave)
ADU (Master)
Modem
ACU
(Master)
ACU
(Slave)
LAN
RX (L-Band)
TX (L-Band)
BUC M&C (RS-232)
ACU M&C (Ethernet)
Keyline (RS-422)
RX (L-Band)
RX (L-Band)
TX (L-Band)
TX (L-Band)
BUC M&C (RS-232)
ACU M&C (Ethernet)
Keyline (RS-422)
Keyline (RS-422)
TX Splitter
RX combiner
