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Complex connections from one truck

Philip Stevens learns more about a new OB vehicle

August 2016 saw the launch of the UK’s first Outside Broadcast (OB) truck capable of transmitting HD and UHD/4K via fibre and satellite simultaneously. Known as TES52, and built by Ely-based Megahertz for the TV OB arm of BT Media & Broadcast, the vehicle has already been used up to three times a week in the coverage of Premier League football matches around the country.

“There is considerable interest in UHD, and during the past year we have provided services with existing vehicles to five different broadcasters in the UK,” explains Mark Wilson-Dunn, vice president at BT Media & Broadcast. “However, this new truck is the first vehicle to be designed for one particular customer who had the requirement for three UHD fibre vision feeds and one satellite connection at the same time. Of course, having said that, it can be used for other applications, too. Using BT’s own fibre network, we can connect to over 150 major sports venues across the UK.”

At each of those venues, the new truck will be located next to the outside broadcast production vehicle, accepting multiple feeds which are then compressed, multiplexed and fed to the broadcaster via the BT Tower in London.

Making choices
TES52 is a step up from the TES51 UHD truck that Megahertz built in 2014. That truck was based on a Mercedes Sprinter framework, while the new vehicle is slightly larger and is built on a 7T Iveco Daily chassis.

“We did a review of the market before selecting Megahertz again for this work – but decided that the company offered the best solution to our unique requirements,” states Wilson-Dunn.

Stephen Burgess, CTO at Megahertz takes up the story, “Our challenge as a systems integrator is always to remain mindful of the weight of the equipment going into the vehicle. What’s more, we must ensure that there is sufficient space and cooling facilities for all the equipment and thereafter to provide the wiring requirements to connect everything together.”

He reports that all vehicles need to have a reliable power source in order to perform well – and continuously. “Megahertz chose the Fischer Panda 12000NE PVMH 10.6 kW / 12.5 kVA generator mounted inside a GRP – 4DS super-silent capsule. The performance and reliability of the Fischer Panda combined with our considerable experience in fitting and maintaining these units, gave BT the confidence they needed for this vital part of the truck.”

Another challenge involved the choice of antenna to meet the high specification for the BT truck. “We needed to find an antenna that provided high gain and stability and be able to operate in harsh environmental conditions. We opted for the 1.8M AVL antenna, which met all the operational criteria from wherever the vehicle would be operating,” states Burgess.

When it came to selecting a router, the Megahertz team opted for the Snell Vega 3G unit.All modern SNG vehicles need to be flexible in the signal being fed into and routed through the system,” says Burgess. “The advantage of the Snell router proved to be invaluable. The flexibility of having a non-symmetrical router and being able to mix and match copper and fibre I/O’s allowed Megahertz to provide a very customised solution and the ability to add or remove or change the I/O configuration as the customer’s needs require.”

The TES52 monitors multiple signals via a 4K Miranda multi-viewer on to a Sony 4K screen, with two 4K/HD Marshall monitors for additional qualitative signal monitoring and an HD Phabrix for test signal generation and checking. The truck supports up to sixteen fibre links in HD mode, or three 4K/UHD and four HD links, using the intelligent video networking platform (IVNP) and BT’s core MPLS (multi-protocol label switching) network. Its on-board, 192-port Snell router is capable of handling a mixture of 4K, 3gbps and HD baseband signals, and ASI transport streams.

Other equipment on board the vehicle includes a Peak PBU, Xicom HPAs, an ETL L-Band Router, a Marshall 4K Monitor and Bluebell Optical Splitters and converters.

Maintaining quality
Wilson-Dunn continues, “We live and die by the quality and reliability of the service we offer, so we have, wherever the appropriate equipment is available, remained with those suppliers that have a proven track record with us.”

He goes on to report that during IBC, BT tested an Ericsson HEVC encoder with this truck. “We used a demo unit and carried by fibre and satellite a live rugby match to Amsterdam. This was the first live demo of a HEVC based link used in the delivery of 4K UHD TV. Using this encoding/decoding technology removes the requirement for complex AVC quadrant based UHDTV contribution.