Feature 5 | COMMUNICATIONS SYSTEMS


and also floats, with its IC-M33 model. Waterproof to IPX-7 standard, this unit can continue working after being submerged to a depth of 1m for 30 minutes, a vibrator function clears the speaker of water after retrieval. The IC-M33 has a rounded body and weighs 305g. Nine large buttons on the front panel facilitate simple operation and the easy-to-read LCD displays the two-digit channel number plus levels for volume and squelch. Features include 5W transmit power, 70 programmable channels, dual and tri-channel watch, battery life indicator, auto-scan and two-step power saver. A lithium-ion battery pack is said to provide up to nine hours of operating time in typical operation. An optional waterproof speaker/microphone can be connected via a screw-type connector. Other ICOM handhelds include


the 6W IC-M71, which has a higher waterproof rating of IPX8 (1.5m depth for 30 minutes), and the popular IC-M31 which is IPX-7 rated. The smallest handheld in the range is the IC-M87E, which is also water-resistant to IPX7 and can be used in severe weather conditions. ICOM also produces VHF base stations that are used in bases ashore that communicate with ships. VHF transceivers are produced by


many other notables including Raymarine with its Ray 49, 55 and 218 series fixed mounts plus Ray 101 and 240 handhelds; Northstar (VHF 710 and 721 DSC VHFs); Furuno, Simrad, Nexus, M-Tech, GME and several others.


Into orbit Predictions in 1945 by writer Arthur C Clarke that orbiting satellites could revolutionise long-distance radio communication have come abundantly true, to the great benefit of the maritime community. ‘Bouncing’ (signals are re-broadcast by transponders) straight- line radio signals from orbiting satellites overcomes range limitations imposed by the earth’s curvature and avoids the vagaries of HF/MF radio communication, albeit at considerable cost. Today space infrastructure enables


ships and shore offices to communicate over global distances, transferring not only voice but also data – to the extent


54


Thrane & Thrane’s SAILOR fl eet broadband equipment.


that moving images, as in TV and teleconferencing for instance, can be


“The revolution began with


Inmarsat, still very much a major player today, although no longer the inter- governmental consortium it started out as in 1979.”


conveyed via broadband-capable satellites. These, along with associated fibre-optic terrestrial networks, can pass data around the world at speeds up to several gigabytes per second. From a maritime point of view,


the revolution began with Inmarsat (International Mobile Satellite


Organisation), still very much a major player today, although no longer the inter-governmental consortium it started out as in 1979. Recent completion of a fourth- generation constellation of


satellites


orbiting the equator geosynchronously enables Inmarsat to offer a range of capability, from the slowest 2.4kbyte/s communication channel up to broadband speeds approaching 0.5MB (more if data compression) and acceleration techniques are used across the entire globe between latitudes 75N and 75S (approximately), an area that encompasses most of the world’s population and routes frequented by shipping. The third highly capable I-4 satellite is now fully deployed in orbit over the Pacific and is (at time of writing) undergoing final tests prior to service entry. The latest constellation along with previous-generation satellites still in orbit enable the new FleetBroadband service to operate alongside existing Fleet 33, 55 and 77 services and legacy low-rate data services such as Inmarsat D and Mini-M. FleetBroadband, which brings the


benefits of broadband and the Internet to mobile seagoing assets, is delivered to users via two types of onboard terminal.


Ship & Boat International November/December 2008


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