The biggest OB vehicle on the streets of Europe doesn’t distinguish itself just by its sheer size. Implementation of unconventional solutions is what makes TopVision’s new HD Ü5 truck a real eye-catcher. One eye-opener is a compact, lightweight, and flexible detail, the consistent use of fibre-optic cabling
Two production control rooms, a large vision control room with two video recording areas together with a separate slow-motion area, an additional editing suite including NLE, and, of course, a 7.1-enabled audio-control facility. Something that sounds like the description of a well-equipped production studio is in fact installed on board a new HD/SD OB truck. However, when made ready for the road, this miraculously spacious vehicle from TopVision, a provider of outside broadcasting services based in Berlin, is not allowed to exceed a length of 16.5 meters and a width of 2.5 meters for use on European roads. Therefore, the trailer has two big telescoping extensions on both sides, plus a smaller one at the rear. All in all, when fully extended, the truck provides a gross floor space of 70 m².
It’s patently obvious that the new TopVision HD Ü5 is built to cover big events. On the one hand, this will be sports events, such as the Football World Cup which dictated the completion date for construction of this truck. The other raison d’être will be concert recordings. Both applications require excellent sound. All the more so now that HDTV formats with multichannel sound are now pretty much the norm on pay-TV sports broadcasts.
The convenient multichannel features were important reasons for deciding to place AURUS in the sound control room, and in fact in the decision to opt for the fully populated AURUS/STAR rack. This includes seven DSP boards, a complement which offers as many different set-ups as required — with a maximum of 300 channels or 128 buses. In practice, configurations will always be somewhere in between, for example, to output the possible maximum requirement of six multichannel mixes for 7.1 formats.
The HD Ü5’s NEXUS audio network matches the scale of the rest of the truck. The matrix accommodates approximately 2,000 inputs, routable to the same number of outputs, including 52 microphone converter boards providing 208 TrueMatch microphone converter inputs. NEXUS offers the possibility of routing and outputting the multichannel formats either discretely or using Dolby-E. In the truck itself, a total of seven stationary Base Devices were installed in the audio control room, the editing suites, and the video recording area. Space is at a premium so all the NEXUS units were configured to be as compact as possible with their audio lines hard-wired using D-Sub connectors. With a NEXUS STAR and AURUS at the heart, these units form a star-shaped audio network.
To this extent, this routing system follows normal OB-truck network topology, even though it is extraordinarily big one. Another seven mobile NEXUS Base Devices and a semi-mobile Base Device for the video-editing suite in the support truck complete the huge network. On the other hand, the method of connecting all these Base Devices to the truck’s NEXUS cannot remotely be described as normal.
For many years, TopVision have enjoyed positive experiences with STAGETEC products and their inherent reliability. TopVision’s Ü4 truck is already home to a CANTUS plus a NEXUS network, including a number of portable Base Devices, so the idea of usung of fibre-optics extensively was no longer particularly unusual. On the contrary, the experiences gained with the Ü4 would be used to challenge the fundamental ideas of the fibre-optic networking concept.
In such an extensive system this is almost unavoidable. Imagine the effort required to cable such an OB vehicle in the conventional manner with all its external gear when starting a project! Up to 28 camera trunks, seven optical lines to the external NEXUS Base Devices, plus any intercom and auxiliary cables would have to be individually installed, with some of them leading to the most far-flung locations. How much simpler would it be to just bundle all these signals onto a few optical fibres?
The intercom signals might, in any case, be transparently forwarded using the NEXUS, so no dedicated intercom cabling would be required. However for the HD Ü5, a different approach is employed. A group of signals, consisting of HD/SDI, NEXUS FOC, intercom, RS422, and Ethernet signals are merged and transferred via one single fibre-optic line. This allows for considerable savings of cabling, weight, and space.
To enable this bundling, so-called »Coarse Wavelength Division Multiplexing«, CWDM, is employed, which offers considerably greater fibre-optic transmission efficiency. To put it simply, different carrier wavelengths — or differently coloured light streams — are transmitted on the same fibre. This technique is often used to optimize the utilization of municipal networks and is even employed to support the internal audio/video infrastructures in some modern sport arenas. A related method is already in use for other purposes in outside broadcasting, for example for the fixed cabling in the mountains at the Skiing World Championship in 2003 at St. Moritz. Amazingly, CWDM is still an absolute novelty in the field of OB-truck cabling where each and every gram of weight saved and second of unnecessary labour avoided counts.
Going Both Ways
The HD Ü5 is equipped with eight of these optical multiplexers, each of which allows 16 transmission channels to be merged. This provides for much cabling flexibility: Up to eight external video and audio equipment locations can be fed with lines for video, audio, and auxiliary signals. Furthermore, the special hybrid cables, a combination of an optical fibre plus an extra power cable, also supply the required power to subscriber units, Base Devices, computers, and can also supply any other ancillary equipment.
In addition to multiplexing and single-fibre cabling, CWDM offers one more benefit. At sports events in a stadium with static optical infrastructure, the OB truck can often directly dock to the local audio and video cables via CWDM. This saves even more cabling effort.
To keep the multiplexer lines as flexible as possible, two frequencies are specified for each service, one frequency for each direction. For example, two wavelengths between 1,500 and 1,600 nm were defined for transmitting audio. NEXUS also supports this frequency range with the latest optical-interface modules, so a costly external transponder for converting the wavelength (light colour) at the multiplexer input could be omitted. Incidentally, TopVision are the first clients to use these new NEXUS optical modules which allow for Base Device connection with the minimum of cabling effort.
And there is yet more news of innovation to come. Two of the mobile NEXUS Base Devices on the HD Ü5 are the first units from the new single-unit range. They are intended for use as I/O interfaces in remote camera locations, for example in combination with the behind-the-goal cameras or roving close-up cameras.
The truck also includes the new KSC manager from BFE, a system agnostic control unit. It allows, for example, NEXUS functions to be remote-controlled. Innovations such as a centralized system for connecting any keyboards, mice and displays to any computers seem almost trivial in this series of special features.
However, there is another superlative to talk about, since this is no radio vehicle, but currently the biggest HD truck in Europe. Sufficient reason for mentioning — in addition to all these sound features — the 28 digital HD cameras.
Intercom subscriber unit included
In an OB truck, each function must be implemented in the most compact manner possible. This is especially true for the multifunction TopVision HD Ü5. Following this theme the HD Ü5 is one of the first trucks to use the new AURUS Intercom Interface, which is integrated into the mixing console control surface and replaces an external subscriber unit for the sound control room. To operate the new intercom functions there are new buttons and rotary controls integrated into the central section of AURUS.
LED displays show the names of the available subscriber units and thus of the persons or targets which can be called.
The new intercom interface offers 20 talk buttons which work with 2 pages, thus allowing 40 different targets to be addressed.