ACR Electronics GLOBALWATCH2 AIS - INSTALLATION MANUAL V1.0 Installation Manual

Also see for GlobalWatch 2 AIS: User manual

Contents

GlobalWatch 2TM AIS Installation Manual 6 Version 1.03.3 Installation of VHF / GPS AntennasInterference to the Ship’s VHF RadiotelephoneThe AIS ship borne equipment, like any other ship borne transceiver operating in the VHFmaritime band, may cause interference to a ship’s VHF radiotelephone. Because AIS is adigital system, this interference may occur as a periodic (e.g. every 20 seconds) soft clickingsound on the ship’s radiotelephone. This affect may become more noticeable if the VHFradiotelephone antenna is located close to the AIS VHF antenna, and when theradiotelephone is operating on channels near the AIS operating channels (e.g. channels 27,28 and 86).Attention should be paid to the location and installation of the various antennas, in order tosupport the antenna characteristics in the best possible way.VHF Antenna InstallationAntenna LocationLocation of the mandatory AIS VHF-antenna should be carefully considered. Digitalcommunication is more sensitive than analogue/voice communication to interference createdby reflections caused by obstructions such as masts and booms. It may be necessary torelocate the VHF radiotelephone antenna to minimize interference effects.To minimise interference effects, the following guidelines apply:• The AIS VHF antenna should have omni directional vertical polarisation providing 3 to 5dB gain.• The AIS VHF antenna should be placed in an elevated position, as free standing aspossible, with a minimum of 2 metres in horizontal direction from constructions made ofconductive materials. The antenna should not be installed close to any large verticalobstruction. The AIS VHF antenna should have a visible sky of 360°.• The AIS VHF antenna should be installed at least 3 meters away from interfering high-power energy sources such as radar and other transmitting radio antennas, and out of theway of the transmitting beam.• There should not be more than one antenna on each level. The AIS VHF antenna shouldbe mounted directly above or below the ship’s primary VHF radiotelephone antenna, withno horizontal separation and a minimum of 2 metres vertical separation. If it is located onthe same level as other antennas, the distance apart should measure at least 10 metres.See also sample for antenna layout in the Appendix.CablingThe cable should be kept as short as possible to minimise attenuation of the signal. Doubleshielded coaxial cables equal to or better than RG214 are recommended.RG214 at VHF attenuation per meter of app. 0,07 dB/m (45m = 3,15db)VHF AIS frequency app. 162MHzAll outdoor connectors on the coaxial cables should be fitted with preventive isolation, suchas shrink-stocking with silicone to protect the antenna cable against water penetration.Y1-03-0183-1 Rev. A