44 TVBEurope The Workflow Wireless goes live
For live productions where even a little break-up is unacceptable, factors like delay times, reliability and frequency availability are crucially important, says David Fox
“THE PRIMARY issue, and becoming more and more so, is the allocation of frequency bands, because we’re going to lose the whole of the 2GHz band at some point to the telephone networks. We are going to be forced to operate at much higher frequencies. Even 3.5GHz won’t be available long term,” says BSI’s Technical Director Tony Valentino. The 2GHz channels will
remain available short term, but eventually he believes all the frequencies from 1.4 to 3.5GHz will go, so broadcasters will have to move to 5GHz and above. “The new challenge is to get performance and reliability at higher frequencies,” he says. BSI provided wireless cameras
to Sky Sports to cover all 20 Formula One races this year at 7GHz. “Given the right receive infrastructure, we’ve made it perform even better than 2GHz, but it has to be more elaborate,” he explains. However, one benefit in
operating at higher frequencies with fewer competing users is that the noise floor is lower, so you get better signal to noise. “With the right antennae, right modulation and set up you’re able to achieve very good results,” he says. For F1, this
High flying: Boxx TV’s latest systems are half the weight for use on mini helicopters
singer was held for two minutes and 20 seconds, which would have been impractical without very low delay wireless systems.
Strictly the business By David Fox
Freelance Steadicam operator Dominic Jackson has worked on the BBC’s Strictly Come Dancing since it was reinvented nine years ago. It started with SD wireless systems, then moved to HD using Link Research systems — but the move to HD brought longer delay times, so the pictures were out of sync. “We couldn’t cut between close up shots because of lipsync, so I couldn’t generally do singers or presenters – although there were ways around it,” he says. However, he wanted less delay, and bought a Boxx
The system uses uncompressed video at 20Mbps, “but, being in the 5GHz bandwidth means we could use
included cameras moving through the garage areas without any break up.
The X Factor ITV’s recent X Factor final used two Boxx TV Meridian zero- delay systems; one on a Steadicam, the other on a shoulder-mounted camera in the audience. The Steadicam was used for one shot where it did two full circles of the singer, Rihanna, close up, where lip sync is essential. For The Voice, on BBC, a moving Steadicam shot of a
www.tvbeurope.com January 2013
High speed: BSI’s mini wireless system used on a NAC camera for Sky Sports at The Emirates Stadium
40Mbps,” says Boxx TV co- founder Scott Walker. While this frequency was almost completely unused by others just two years ago, there is now a lot more demand for it, particularly from smartphones. However, this just means it requires a bit more planning. Walker uses an inexpensive USB spectrum analyser plugged into a laptop to see what else is using the spectrum and then chooses the best channel available.
Even in the biggest locations, such as the Wembley Arena, with 10,000 people, there haven’t been issues finding a channel. As the silicon it uses for its products is Wi-Fi-based there wouldn’t be any easy way of moving to another part of the spectrum. Even so, this shouldn’t be a
problem for most shows. It did a reality show, Cake Boss, in New York for TLC, with the camera facilities company Hotcam, where there were eight wireless cameras in a confined area with little difficulty.
Meridian system. “It has to go through a synchroniser, so it takes a frame, but it’s still two frames better than anything else on the market,” he says. Jackson uses other RF systems as well, for other types of programming, “but for live studio productions I prefer the Boxx, but it wouldn’t work as well in a big open air concert because the signal works best if it bounces off lots of walls.” However, he has used it in bigger spaces, such as Wembley, where it performed well, although the more people there are around you, the more of the signal they absorb.
However, “it seems to be doing better than I was expecting. In Wembley I was ready to put up three or four receivers, but it worked off just one despite there being thousands of people in the arena,” he says. “The fall off is more subtle
as it fails. The blacks get very noisy initially, and it looks like there is a lot of gain, which is a way of keeping the colour and highlights going, and is certainly much better than it breaking up. In the environment I work in, it works very well. I can give almost in-sync pictures.”
Jackson does a lot of awards
shows, so being able to have presenters walking and talking with a prompter without any issues is a big bonus. Previously he would only have done such shots if they were edited later and the audio track re-synced. “If you want the best results
it still requires careful set up and use,” says Jackson, which is why he employs an RF engineer. He also has a back- up system for live use. “Where people have had problems it’s because they haven’t been careful enough,” such as using a spectrum analyser, he says.
Well modulated BSI hopes to launch a DVB-T2 based system at NAB, which will allow it to run more robust modulation schemes at a higher bitrate within the same bandwidth. Using DVB-T 16QAM 2/3 modulation gives about 15Mbps, but with DVB-T2 this could also be achieved using the much more robust QPSK modulation (whereas DVB-T QPSK would only give 6-7Mbps). It will also work better at higher frequencies than 16QAM. Some manufacturers use MIMO (Multiple Input, Multiple Output), which can double the power and reach of signals and is used extensively for Wi-Fi. These are typically in the licence-exempt range, and
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