Chapter 2 Installation Guide; C-Nav Antenna Installation Notice; Standard Antenna Installation; Antenna Location - C-Nav IALA Hardware Reference Manual

C-Nav Hardware Reference Guide
Chapter 2 ........................................................... Installation Guide

C-Nav Antenna Installation Notice

This manual provides guidance on hardware installation for optimum performance.
Prior to commencing any installation, discuss proposed mounting locations/methods and cable
routes with the vessel chief engineer or master to ensure that all parties are aware of the work
to be done and the risks involved.
Always wear appropriate protective equipment, including a certified fall arrestor harness
and hardhat when working at heights to prevent injury to personnel, or death. Prior to
commencing any work on the mast, ensure that all radar systems are switched off and
isolated.

Standard Antenna Installation

Antenna placement is critical to good system performance. It is necessary to mount the antenna
as high on the mast as possible in order to avoid antenna shading by surrounding structures.

Antenna Location

When choosing an antenna location, consider the following:
 Locate the antenna as high on the mast as possible, where it has a clear view of the sky,
to an elevation angle of 7º if possible. Obstructions below 15º elevation generally are not
a problem, though this is dependent on satellite availability for the local region.
 Avoid placing the antenna where more than 90º azimuth of the sky is obstructed. When
more than 90º of azimuth is shaded, it is often still possible for the reciever to navigate,
however, poor satellite geometry (due to satellite shading) will provide poor positioning
results.
 Avoid placing the antenna on or near metal or other electrically reflective surfaces.
 Do not paint the antenna enclosure with a metallic-based paint.
 Secure the antenna to the mast firmly to avoid wind and vibration which can affect the
performance of the system.
 Avoid placing the antenna near electrical motors (generators, air conditioners,
compressors, etc.) or other sources of interference such as radar systems, satcom
domes, HF antennas or whip antennas.
 Do not place the antenna too close to other active antennas. The wavelength of L1 is
0.19m and L2 is 0.244m. The minimum acceptable separation between antennas is 1m
(39 in), which provides 6dB of isolation. For 10dB of isolation, separate the GPS
antennas by 2.5m (8ft), and for 13dB of isolation (recommended) separate the antennas
by 5m (16ft).
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