Yearly Archives: 2017

Far offshore windfarms present communications challenges

This is an interesting article debating the different types of communication that can be used over a long distance, and as they distance moves further and further, the different types of communication drop off or become part of an infrastructure. As engineers battle with this problem, knowledge of how radio frequencies and applications becomes paramount.

As offshore windfarms are built further and further from land, alternatives to conventional VHF communications are going to be required

A cornerstone of any major project is clear communication between all parties. As we move windfarm construction further offshore, maintaining efficient voice and data communications becomes essential. With many projects now being constructed beyond the range of VHF radio and cellular telephone, such as a Gemini or Dudgeon offshore windfarms, crew transfer vessel (CTV) operators and their clients are experiencing challenges achieving practical and affordable offshore communications. My experience on two far offshore projects in the last 15 months has shown that creative thinking can work together with existing equipment such as TETRA radio to reduce the risks and stress that poor communications can generate.

Communication solutions on offshore windfarms depend on the phase that the operation is in, the size of the project and the distance from shore. Many smaller, older windfarms rely on VHF radios to communicate between shore and vessel and shore/vessel and work team on the turbines. However, VHF is limited in range being a line-of-sight system, and the signal has trouble penetrating structures such as wind turbines due to the Faraday cage effect. Conventional cellular telephone coverage is also possible on nearshore sites, with some windfarms installing a cellular mast within the windfarm. Vessels at anchor off the Dutch port of IJmuiden can thank the windfarm industry for good connection when waiting for a pilot if they have contracts with the provider KPN.

When moving further offshore, luxuries such as a cellular mast will not be installed during the construction phase, and it is most likely that VHF radios will not be sufficient. It is common for the developer to install a TETRA radio network – similar to those used by national emergency response services such as police and fire departments.

TETRA, or terrestrial trunked radio as it is properly termed, is a secure network allowing one-to-one, one-to-many and many-to-many communications. This means that the marine controller can speak directly and privately to one party or to the entire offshore spread depending on what is needed. It transmits on a lower frequency than VHF so covers a greater range. This still is not enough to cover the distances experienced on far offshore windfarms. If multiple base stations are used, each base station can then automatically rebroadcast a message thus expanding the network coverage. On a recent construction project, it was found that there were communications blackspots in the area of the sea passage from the base port to the site. This was later eliminated by fitting full base station units rather than just handheld transceivers on the CTVs. The CTVs then became vital links in the communications network and ensured the blackspots were reduced or eliminated altogether.

TETRA has many other advantages, including the ability to penetrate the tower of a wind turbine, and calls are not dropped when moving between base station carriers due to the network configuration. This is especially important if vessel-carried base stations are relaying far offshore. The network is also secure, which ensures that commercially sensitive information cannot be intercepted. With the one-to-one mode, it also means that managers can have detailed conversations on sensitive subjects.

However, anecdotal information received from vessel crews in the field appear to indicate that TETRA, although a good system, is not foolproof. One vessel master reported that, after 15 months on site, they still had blackspots with TETRA and sometimes have to use the cell phone application WhatsApp to request that turbines be started or stopped so that he can land a team.

TETRA does not solve the operational problems experienced by vessel-operating companies who require frequent voice and data communication with the CTVs to ensure a smooth delivery of service. As most sites far offshore are outside of cell phone coverage and clients demand that daily reports are issued on time, creativity is needed. There is a simple solution that could solve all of the communication problems far offshore – installing VSAT satellite communications on each CTV, which allows instant telephone and data transfer.

However, the practicalities of chartering in today’s windfarm industry eliminates this option, as the client will not want to pay for installation and operation, and a vessel owner cannot afford such a luxury. Charterers therefore need to make a decision: either they assume responsibility and the costs for practical workable satellite communications on their vessels or look for practical alternative solutions to deliver what is needed far offshore.

One practical solution to maintain communications between the marine co-ordination centre and vessels is to step back a generation and use medium frequency/high frequency single side band radios, which are common equipment on larger CTVs and is standard on service operation vessels (SOVs) or installation vessels.

When used in conjunction with the digital selective calling (DSC) function of the GMDSS standard, voice communications can be maintained at long distance without operating cost. Unfortunately, current guidance for the marine co-ordination in windfarms as found in the G9 Good practice guideline: The safe management of small service vessels used in the offshore wind industry does not yet consider marine co-ordination and communications in far offshore windfarms.

Another practical solution to improve data communication is to install powerful WiFi antennas on the decks of SOVs and other major offshore assets to allow CTVs to have internet access when they are in close proximity. CTVs can then download passenger manifests and weather reports and upload the daily progress report and synchronise planned maintenance and email systems.

CTVs spend considerable time in close proximity to the SOV during passenger transfer, bunkering or waiting for the next assignment, and it is relatively easy to set up the computers to connect and synchronise without operator input, thus reducing the risk of distraction. SOVs should be designed with space for CTV crews to use as a secure office so that laptops can be left connected to the network. In this way, crews can have two computers and prepare work when on shift, transfer via a data stick and upload when they go off shift.

One of the most effective tools that we have identified is WhatsApp, which seems to require very low signal strength to connect and transfer brief messages. On recent projects, we have found that most vessel/office communication occurs in this medium, including fault finding and incident reporting and investigation. Crews have found it quicker to video a CCTV system playback and send via WhatsApp than download the CCTV video and send it via a file transfer service. As synchronising an electronic planned maintenance system offshore is very time consuming, our superintendents have taken to sending the worklists via WhatsApp to the vessels who then confirm back with text or images when a job is complete. The superintendent then does the PMS administration from their office with the advantage of high speed network connections. Experience with WhatsApp has led me to believe that agile, low data applications will form part of the future of offshore communication.

Far offshore projects have moved from planning and dreaming to reality. However, effective and cost-efficient communication solutions have not moved with them. Like most challenges with far offshore windfarms, there is no single solution, but experience has shown that, with creativity and flexibility, projects can communicate with their teams and operators can manage their vessels.

Better equipment earlier on in the construction phase, such as MF/HF radios in the MCC and on the vessels, TERA base stations on the vessels and open deck WiFi on construction assets will all assist in improving safety and reducing stress while ensuring that unnecessary costs are not incurred.

Chinese corporation bids to acquire Sepura

This news is making quite a buzz within the stock market forums, With two of our big players in our industry set to merge, this is huge news! Yes, Sepura have had their problems this year and Hytera have increased their market share, but we are not sure is this is good news or bad?

Another Asian corporation is set to hoover up a Cambridge UK technology company in a state of financial flux.

Communications technology business Sepura confirms it is in talks with Chinese company Hytera Communications Corporation Ltd.

It will be an all-cash deal but the acquisition price will be moderate because digital radios company Sepura is in a mess because of cash liquidity issues.

Sepura revealed the takeover talks after its share price spiked more than 25 per cent having nosedived in recent times due to cashflow issues and order delays.

Hytera is a world leading solution provider of professional mobile radio communications and operates globally.

Late today, Sepura issued a statement on London Stock Exchange confirming it was in preliminary talks with Hytera regarding a possible offer for the entire issued and to be issued share capital of the company.

Hytera confirmed to the Sepura board that any offer was likely to be solely in cash. The usual caveats were issued that there was no certainty any deal would go through and shareholders would be updated on new developments.

Founded in 1993 in Shenzhen, China, Hytera has grown to be a key player in the PMR (Professional Mobile Radio) communication industry with a large customer base in more than 120 countries and regions across the world.

In China, Hytera’s market share ranks first among Chinese manufacturers while globally Hytera has reached second place in the overall terminal category.

As one of the few corporations that masters TETRA, DMR and PDT technologies, and produces all series of products and solutions of all these mainstream digital protocols, Hytera leads in the draft of digital trunking standard in China.

Its acquisition of the Rohde & Schwarz TETRA business in August 2011 further strengthened its competitive edge in TETRA market.

Hytera has established a global sales network with 30 branches in the US, UK, Germany, Australia, Brazil and other territories and through  600+ partners across the world.

Hytera has an R & D team of over 1200 engineers in five research centres. Sepura won the Business Weekly Awards Business of the Year title in March after a record-breaking

2015 but hit liquidity problems this summer and has temporarily lost its CEO Gordon Watling to ill health.

http://www.businessweekly.co.uk/news/hi-tech/chinese-corporation-bids-acquire-sepura

How Many Walkie-Talkies Can Operate on the Same Channel?

Theoretically, you can use an unlimited amount of walkie-talkies on the same channel (although in practice you might experience a few problems if you took that suggestion literally). Basically, there isn’t really a set limit. You could use as many as you like provided they are set up correctly. Anybody set to the right channel and in range at the time of transmission would then be able to pick up the signal and respond to it.

Most radios have access to 8 channels. These channels each have 38 separate ‘identification tones’. The user sets his/her channel up with the desired tone and then only other users who know the channel/tone will be able to hear the transmissions. As a result, there are, in any given area, about 304 different combinations, so signal interference is unlikely to affect you.

Please do not interpret this answer as saying that your radio has access to 304 possible channels. It does not. It will likely only have access to 8. Some less reputable manufacturers tend to falsely imply access to 304 channels; this is simply not the case. You will have access to 304 possible tone/channel combinations, that’s all.

To better explain the CTCSS codes and how they work; we’ll include a little information from Amherst.co.uk’s FAQ page.

“CTCSS stands for “Continuous Tone Coded Squelch System”. These codes are also often called “Privacy codes” If a CTCSS tone is selected; a CTCSS sub-audible tone is transmitted along with the regular voice audio by the transmitting radio. The receiving radio, set to the same CTCSS tone, will only receive audio if it contains that sub-tone. Interference from other users on the same frequency is therefore rejected (unless they are also on the same sub-tone). This is a way of allowing groups of users of walkie-talkies on the same channel to avoid hearing messages from other nearby users”.

So, in conclusion, you can probably use as many walkie-talkies as you like on the same channel. As long as the units in question are of the same type (either VHF or UHF) and have the same CTCSS setup, then you simply shouldn’t have a problem. You also shouldn’t suffer from signal interference due to other users (although you may still experience signal loss/interference/degradation from other sources). We have talked about combating signal loss elsewhere, so please see the other questions if you have any problems in this area.

I Bought a Two-Way Radio With a Range of 25 Miles…Why Won’t It Work?

Sorry, but you’ve been had. Although many manufacturers boast that their radios can reach amazing distances, this is, in almost every instance we’ve encountered, a fallacy.

How is this legal, you may ask?

Essentially, your radio quite probably could work over a range of 25 miles, but that is a theoretical estimate, working on the assumption that the myriad variables that affect two-way radio signal (such as atmospheric conditions, topography, objects in the way and etc) are simply not in effect.

All of them. At the exact same time.

So, assuming that you used your two-way radio in a vacuum, where weather didn’t exist and no obstacles, man-made or otherwise, were present, you would be able to communicate with someone else who was further away in that impossible vacuum, maybe even 25 miles away, but otherwise? Forget it.

The fact is that the average two-way radio has a range of between one and two miles and not much more (maybe three, but we’re not making any promises). CB radio fares significantly better, largely because it makes use of large aerials. Now, Signal-boosting equipment can be used to improve your two-way’s performance (for example, repeaters), but such equipment is expensive and hard to obtain for legal reasons.

There are, however, a few factors that can have an affect on your radio’s range. The frequency being used, the power output, the size of the antenna, the complexity of the signal being sent, signal interference, background noise and (as we wrote earlier) objects in the way are all factors that can improve (or hamper) your efforts to get your signal to reach as far as possible.

So, talking on your radio whilst in the car will have a deleterious affect on your signal, as will deliberately walking through wooded areas or places with a lot of rocks/mountains if you can take an easier path.

However, a larger antenna (if you’re tech orientated, the antenna can be replaced with a better one – although this should only be attempted if you are

  1. a) Sure about licensing laws

And

  1. b) Tech savvy enough to void the warranty and not regret it later, can really add a few hundred meters to a radio’s range, as can a switch in frequencies.

Also, your choice of VHF or UHF radio will have an affect as well, a UHF signal, for example, generally penetrates buildings and objects better than a VHF signal, whereas VHF is better for outdoor use where there is a lot of open space to transmit across.

Having said/written that, even in optimum conditions, you are extremely unlikely to transmit over a distance of 25 miles. Sorry.

As an aside, mobile phones don’t suffer from this lack of coverage, largely because cell towers are in place that bounce the signal from one to the other and thus carry it across a far larger area, your mobile is still your best bet to break that 25 mile mark, we’re afraid.

If you really must use radio communications over long distances, we recommend going to the Website 2wayradionline.co.uk

Hope that helps.

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