JRC JHS-183, Installation Manual

Page: 37 / 102

PREPARATION FOR INSTALLATION
2-3
2.2
Installation Location of AIS Transponder and Controller
Give consideration of electromagnetic wave interference with other equipment when installing the AIS
transponder. When deciding installation location for the controller, factors such as checking indications
and ease of operation should be taken into consideration. This section describes how to install the AIS
transponder and controller.
2.2.1 AIS Transponder
Since the AIS communicates on the VHF maritime band, it is vitally important to pay attention to the
physical relationship to VHF radiotelephone antennas. In addition, it is important to check the
relationship to MF/HF antennas, Inmarsat, radar scanners, etc.
(1) The relationship between the VHF/GPS antennas and other antennas
(IMO SN/Circ. 227 Guidelines for the installation of a shipborne AIS)
The safety distance for radio frequency interference for each antenna is described in the IMO
document SN.Circ.227. These contents are shown below (in List1, List2). A VHF antenna and
GPS for positioning are necessary for AIS. These contents are shown in Figure 2 for ease of
understanding.
List1
Installation location of AIS VHF antenna
1. Relations between structures
(1) At least 2m off from electric conductor
structures
(2) Away from a large vertical obstruction.
(3) AIS VHF antenna gain:
Vertical 3-5dB
(4) Horizontal visibility for AIS VHF antenna:
360 degrees
2. Relations between high-power transmitting
set (e.g. radar, radio)
(1) At least 3m off
(2) At least 3m away from beam
3. Relations with VHF antenna
(1) At least 2m off and it should not be located
at same horizontal level.
(2) In case these are located at same
horizontal level, at least 10m away with
each other.
List2
Installation location of GPS antenna
1. Relations with structures (e.g. mast, boom)
(1) No radio interference by mast, boom etc.
(2) Visibility interference by mast, boom etc:
within 2-3 degrees
(3) GPS antenna: a clear vertical visibility
(4) GPS antenna horizontal visibility
360 degrees
2. Relations between high-power transmitting
set (e.g. radar, Inmarsat, VHF antenna for AIS)
(1) At least 3m off
(2) At least 3m away from beam