User's Manual

5 Setting up the Receiver
64 SPSx50 Modular GPS Receiver User Guide
• the receiver is not exposed to moisture extremes (such as rain, snow, water
blasters, or wash systems)
• the receiver is protected from mechanical damage
• you can connect and disconnect cables without placing undue stress on them
Mounting the antennas
It is critical that you install each antenna at the correct location. Poor or incorrect
placement can influence accuracy and reliability.
Ideally, mount the two antennas as far apart as possible and at about the same height
on the structure. Mount the antennas fore and aft along the vessel centerline or on a
line that is at a known orientation to the centerline. Always mount an antenna at a
location that ensures a good view of the sky.
Follow these guidelines to select the antenna location:
• Choose an area with a clear view of the sky. The antenna must be above any
metallic objects.
• Do not mount the antenna close to stays, electrical cables, metal masts, or other
antennas.
• Do not mount the antenna near a transmitting antenna, a radar array, or near
satellite communication equipment.
• Avoid areas with high vibration, excessive heat, electrical interference, and
strong magnetic fields.
Use a 5/8" stainless steel bolt to mount each of the antennas. There is a threaded bolt
hole in the base of the antenna.
Configuring the receiver pair
One of the receivers must be nominated as a Heading unit. The other receiver is
nominated as a Moving Base unit. For this configuration to work, you must use the
Marine heading cable (P/N 57169).
To set up the Heading unit:
1. From the Home screen press <enter><enter>. The Mode screen appears.
2. Select Heading mode. The SPSx50 display shows two extra settings for heading:
– Heading Adjustment. Enter a positive value in decimal degrees. The value is
applied to the raw heading value before it is output in the NMEA HDT
message or displayed on the front panel of the receiver. This value is used
when the two antennas are not mounted parallel to the vessel axis.