COBHAM Sea Tel 9711-56 IMA C Band, Руководство по установке

Страница: 17 / 234

Sea Tel 9711-56 IMA Site Survey
3-1
EAR Controlled - ECCN EAR99
3. Site Survey
There are three objective of the site survey. The first is to find the best place to mount the antenna and the BDE. The
second is to identify the length and routing of the cables and any other items or materials that are required to install
the system. The third is to identify any other issues that must be resolved before or during the installation.
3.1. Site Selection Aboard The Ship
The radome assembly should be installed at a location aboard ship where:
•
The antenna has a clear line-of-sight to view as much of the sky (horizon to zenith at all bearings) as
is practical.
•
X-Band (3cm) Navigational Radars:
• The ADE should be mounted more than 0.6 meters/2 feet from 2kW (24 km) radars
•
The ADE should be mounted more than 2 meters/8 feet from 10kW (72 km) radars
•
The ADE should be mounted more than 4 meters/12 feet from 160kW (250km) radars
•
S-Band (10cm) Navigational Radars:
•
If the ADE is/has C-Band it should be mounted more than 4 meters/12 feet from the S-band
Radar.
•
The ADE should not be mounted on the same plane as the ship's radar, so that it is not directly in the
radar beam path.
•
The ADE should be mounted more than 2.5 meters/8 feet from any high power MF/HF antennas
(<400W).
•
The ADE should be mounted more than 4 meters/12 feet from any high power MF/HF antennas
(1000W).
•
The ADE should also be mounted more than 4 meters/12 feet from any short range (VHF/UHF)
antennae.
• The ADE should be mounted more than 2.5 meters/8 feet away from any L-band satellite antenna.
•
The ADE should be mounted more than 3 meters/10 feet away from any magnetic compass
installations.
•
The ADE should be mounted more than 2.5 meters/8 feet away from any GPS receiver antennae.
•
Another consideration for any satellite antenna mounting is multi-path signals (reflection of the
satellite signal off of nearby surfaces arriving out of phase with the direct signal from the satellite) to
the antenna. This is particularly a problem for the onboard GPS, and/or the GPS based satellite
compass.
•
The ADE and the BDE should be positioned as close to one another as possible. This is necessary to
reduce the losses associated with long cable runs.
•
This mounting platform must also be robust enough to withstand the forces exerted by full rated
wind load on the radome.
•
The mounting location is robust enough that it will not flex or sway in ships motion and be
sufficiently well re-enforced to prevent flex and vibration forces from being exerted on the antenna
and radome.
• If the radome is to be mounted on a raised pedestal, it MUST have adequate size, wall thickness and
gussets to prevent flexing or swaying in ships motion. In simple terms it must be robust.
If these conditions cannot be entirely satisfied, the site selection will inevitably be a “best” compromise
between the various considerations.