Some countries in Scandinavia are already using TETRA for the police inshore and the coastguard, said Raúl Carpio, business solutions manager. “In the UK”, he went on, “county police forces with stretches of coast to monitor have marine units and marine inspection units, which intercept and inspect incoming vessels such as cargo ships and ocean-going yachts.

“Because of the hazardous materials they may find, e.g. explosives, they purchase and use a small number of ATEX – intrinsically safe – terminals. These will only be used on the occasions when they are inspecting such vessels, so they will not be in everyday use.”

For those users who require dedicated ‘onboard’ equipment in waters such as the North Sea, equipment from Motorola Solutions and Zenitel’s VINGToR product family can provide onboard communications within a vessel, interoperating between DECT, VHF and TETRA.

Oil and gas

Bjørn Rasmussen, Motorola’s sales manager for Nordic subscribers, added: “We see a clear tendency now, especially on new oil rigs and for ship-to-shore communications, that they are going for TETRA due to many features which surpass the previous analogue systems.

“There was a major event at the end of October in Stavanger in Norway where users in the oil and gas industry stated they are going to change their older systems to TETRA, replacing analogue ATEX radios and also using repeaters for range.

“In the past year they have ramped up their pace of upgrade to TETRA so they can use it for telephony and security, connecting several oil rigs to the same system in a cluster. But what they are able to do is install a lot of the TETRA-related equipment on the shore side – the switches and servers – without having to install much on the oil rigs. All they need at sea is the base station to connect several rigs over an area of several square kilometres. 

“For emergencies, or just daily use so they can maintain day-to-day standard communications between rigs, TETRA handles everything. The exact ranges being achieved depend on how the base stations are deployed. But the oil field network will have its network plan and part of the equipment used will include repeaters to expand coverage.”

At sea, at speed

Meanwhile, in the Nordic area and also in Middle Eastern countries, emergency forces which have converted to TETRA for land operations, including police and fire departments, are more and more equipping their lifeboats and ribs with the technology. In this way, inshore crews can keep in touch with their land-based command and control centres.

“This is a challenge because normally when you are racing at high speed on sea to a rescue or interception, there is a huge amount of wind that would normally make voice comms very difficult”, Rasmussen continued. “Motorola has been doing some trials with microphones and headsets as well as speakers on the boats so the crew can hear the communications from shoreside without being drowned out by the wind noise. And when you’re in the North Sea this is a real issue!

“This has actually been installed with almost all the police and fire service rib boats and lifeboats around the coast of Denmark, and this tendency is also being followed in Sweden. However, this does not remove the need for these vessels to also carry analogue VHF radios in line with international maritime laws, so they can communicate offshore/at sea with other vessels and helicopters.

“What we are seeing is that in sea nations like Denmark it appears the Scandinavians are quite ahead of the rest in using TETRA. The Danish and Swedish coastguards are using TETRA already and are very happy about the call quality.”

Installation requirements

Carpio added that some Scandinavian coastguard forces have installed fixed mobile terminals in their boats, but these must pass a special interference test to ensure that there is no interaction with other equipment, especially the compass. They must meet the ‘Compass Safe Distance’ requirements.

Water protection is also crucial, and here Motorola offers one unit which achieves an ingress protection rating of IP67 without the need for an additional housing. The first figure relates to the level of dust protection, and it is the second, the 7, which relates to water and is relevant to operations at sea. Equipment with a 7 will continue to work after
being submerged for 30 minutes. Equipment with a lower rating may need to be housed by the installer in waterproof casings.

Some TETRA deployments 

So where is TETRA being used at sea?

Norway

In 2009, Zenitel delivered Motorola TETRA systems to the Ormen Lange gas refinery and field on the west coast of Norway, the second largest gas field on the Norwegian continental shelf. The equipment initially supplied included Motorola’s Dimetra IP Compact TETRA infrastructure and ATEX TETRA radios with GPS positioning. Zenitel’s own repeaters, from its Zenitel Confined Area Solutions family, are being used to expand radio coverage. Its Radioteknik TETRA repeaters are available in many options to meet any the widest variety of applications, including offshore coverage.
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