Installing The Antenna - NorthStar GM1708 961X Installation Manual

SECTION TWO - Installation

Installing the antenna

Choosing an
antenna
Choosing an
antenna location
Page 14
Connectors
Power connector (3-wire)
•
TNC connector (control head #1)
•
TNC connector (control head #2)
•
I/O #1 interface connector (18-wire)
•
I/O #2 interface connector (18-wire)
•
GPS antenna connector (BNC)
•
DGPS antenna connector (UHF)
•
PC connectors (variable)
•
VGA
•
Three antenna choices are available for the 961X or 961XD:
one for reception of GPS-only signals (the standard one-piece
•
"active" AN150 antenna)
one for reception of both GPS and DGPS signals (a two-piece
•
antenna system comprising the standard AN150 GPS antenna and
the 8410 DGPS coupler)
one for reception of both GPS and DGPS signals (optional one-piece
•
AN205-P "combination" antenna)
Choosing the AN150 antenna location
The GPS receiving antenna is a vital link between the unit's receiver and
the outside world. Aesthetics and easy access should be secondary to pro-
viding strong and reliable GPS signals to the unit's receiver. You should
select a location for the antenna that meets the following requirements:
The antenna should have a reasonably clear view of the horizon,
•
but be no higher than necessary (side-to-side motion of the
antenna caused by rolling of the vessel may degrade the SOG and
COG readings); however, the antenna should be 12 to 18 inches
above the surrounding surfaces to avoid interference.
The antenna must be out of the radiation path of any on-board
•
radar sets or strong magnetic fields.
The antenna must be lower than any INMARSAT communications
•
antenna.
The antenna should be as far as possible from other high-power
•
transmitting antennas.
Watch out for electromagnetic "shading" of antennas from rigging,
•
other vessels, shoreline buildings, and so on. Secure the cable well.
961 INSTALLATION MANUAL Revision A