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HD ENG Takes Flight

Feb 9, 2006 1:00 PM, By Michael Goldman

TV stations carefully navigate the conversion of news helicopters to HD systems.

Back in 2004, in the early days of an initiative to upgrade their station's technical capabilities for HD, officials at KUSA in Denver decided to configure the station's news helicopter for aerial image capture in 1080i HD. At the time, of course, this presented a host of complications because the station had no template to follow — there were no fully HD-capable news helicopters operating at any TV station back then. KUSA not only had to outfit a flying HD ENG ship, it also had to do so within the context of an existing standard-def infrastructure and viewership.

“At the time, there was no book, no one at other broadcast stations to call and ask what to do to get an HD ship launched,” says Don Perez, KUSA's director of engineering. “We wanted to do it as part of an overall initiative to do HD news, and an HD helicopter was meant to be a big part of that. But most stations were focusing on other changes instead. People had been doing HD from aircraft in production settings, but not for live news, and, therefore, the frequencies and bandwidth that were available were not tailored for an HD ENG environment. We had to design our system for the future ENG environment more than the existing environment. But, like most other things, we simply set goals and found reliable vendors.”

The station used Helinet Aviation Services of Van Nuys, Calif., to configure the helicopter, and Microwave Radio Communications of North Billerica, Mass., to upgrade microwave transmission capabilities.

“We engaged in a real team effort to do lab tests, and then field tests, find the components we needed, and get the whole thing up and running,” Perez says. “But there was lots of R&D involved, especially for encoders, decoders, modulators, all of that stuff.”

Two years later, there is a template, better equipment, and more experienced vendors and specialists available to help broadcast stations undertake such HD conversions of their aerial newsgathering capabilities. And yet, as of press time, only two other stations — KABC in Los Angeles and, most recently, WNYW FOX 5 in New York City — have successfully followed KUSA's lead and debuted HD news copters.

To accomplish their goals, all three stations contracted with Helinet to outfit their HD ships, and to help with a wide range of technical upgrades in the air and on the ground.

A longtime provider of ENG helicopters to the news, law enforcement, and entertainment industries, Helinet was the only company capable of offering full integration services to KUSA, KABC, and WNYW, according to officials at those stations. This is largely because Helinet also owns Cineflex, makers of the proprietary Cineflex HiDEF V14 aerial camera technology. The system was designed by Cineflex founder John Coyle, and engineering/system integration company Geneva Aviation implemented a solution to incorporate Cineflex into the other technology on the helicopters. Helinet also provides contract HD aerial broadcast services to stations and networks around the country, and has been outfitting HD news helicopters in other countries. During Hurricanes Katrina and Rita, the company provided exclusive pool HD aerial imagery of the devastated areas to all major broadcast and cable networks.

“[At press time] we had just launched the HD copter for WNYW, and another for TV Azteca in Mexico, and right now we are talking to several stations about re-tooling and retrofitting their equipment to handle HD bandwidth,” says Alan Purwin, founder of Helinet. “Stations have been taking their time making this change because it has to be done within the context of the rest of their infrastructure's switchover to HD, but now that Denver, Los Angeles, and New York have gone ahead, and after the reaction to our imagery that was broadcast around the world during Hurricane Katrina, we are seeing a lot of traction right now.

“An imbalance is created in markets where one station shows up with an HD copter, and that makes a huge impact. So they will all be going in this direction, and to do it correctly you need to deal with all three pieces of the puzzle simultaneously — the helicopter itself, the HD camera system, and engineering the whole thing to work with your existing infrastructure.”

In the air

Plugging a shiny new HD ship into an existing broadcast scheme built for the SD world is the most challenging part of the entire enterprise, officials at KUSA and WNYW say. Al Shjarback, WNYW vice president of engineering, ought to know — he supervised that station's HD helicopter debut last November. Dubbed SkyFox, the ship was outfitted with the Cineflex HiDEF V14 aerial camera system and multiple band microwave capabilities, among other upgrades.

“In our case, we chose a brand-new helicopter [an American Eurocopter A-Star B2], which made more sense than converting our older helicopter,” Shjarback explains. “The old copter would have required major work, along with substantial down time. After our discussions with Helinet, it became clear that it made more sense to kill two birds with one stone — building a new helicopter that would be more cost-effective from a maintenance standpoint, while allowing us to follow an upgrade path into HD without disturbing our current [SD] operation.

“We ended up with a system that captures a true HD signal, which is downconverted for our SD broadcast while simulcasting the HD version. But even those watching the standard-def broadcast get an advantage, since their signal is starting off with a better base resolution. Other HD improvements also translate to our SD broadcast, like a more stable picture and clearer images captured under low-light conditions. But we had a lot of things to think about as we made this change.”

The first part of the HD news copter puzzle was solved by Cineflex and Helinet with the debut of the Cineflex HiDEF camera system a couple of years ago. Cineflex's John Coyle designed and implemented a gimbal technology with a specially configured slip-ring that solved the problem of permitting an HD camera to rotate on the nose of a helicopter at 360 degrees while still pumping a full bandwidth HD 1080i signal back into the helicopter's control center for compression and transmission to a receive site below.

Coyle and his Helinet colleagues are understandably reticent to explain the proprietary aspects of how the Cineflex gimbal manages the robust camera signal, but they say one key component was the ability to keep the gimbal lightweight. This was thanks mostly to the ability to split a Sony HDW-F950 camera's optical system (outfitted with Fujinon ultra-long zoom lenses with motorized 2X extenders) from the camera body, permitting the aerial capture of uncompressed 4:4:4 RGB 1080i footage. Coyle reports that Sony's new HDC-1500 portable camera will eventually be incorporated into future versions of the Cineflex scheme, possibly as soon as this summer. That development will permit users of the system to acquire 1080p imagery, or any combination of 1080i and 720p that they desire, making it easier to capture HD footage in the required and evolving formats of some broadcast networks.

“For ENG use from the nose of a helicopter, the gimbal must be able to rotate 360 degrees continuously, so we had to separate the HD camera system in order to keep the gimbal light and nimble,” says J.T. Alpaugh, Helinet's chief technology officer. The entire unit is just 14½in. in diameter and weighs 67lbs. “But separating the camera presents challenges — taking the signal from an HD optical block, passing it through the gimbal that is constantly turning 360 degrees, and passing that bandwidth on to the camera body and the whole brainbox of the system inside the helicopter. John Coyle's slip-ring solved that problem, and we are able to get the signal to the auxiliary box with no loss of signal quality. Exactly how we do that, of course, is proprietary.”

Once the signal reaches the helicopter's auxiliary control box, where the camera body is embedded, it is recorded to an HD onboard recorder (most Helinet HD copters include either Sony HDW-250, HDWS280, or Panasonic AJ-HD1200A recording decks). Simultaneously, the signal enters a compression, encoding, and transmission path on its way to the broadcaster's receive site. Helinet uses a proprietary compression and encoding codec to make the HD signal transmittable up to 100 miles away, and it then pushes that signal using a high-gain, directional digital microwave system on a direct path to the receive site. There, the signal will be instantly uncompressed and decoded for HD broadcast, or for downconversion for SD broadcast.

“There are not a lot of encoders that are the right size or weight and have the right power consumption for use on a helicopter that can handle this kind of bandwidth,” explains Ron Magocsi, Helinet's director of engineering. “Right now, we are using [NEL HE1100 encoders from Japan's NTT Electronics] or Hitachi encoders for ENG configurations. In any case, the encoder compresses the HD base-band video down to what we call an ASI stream — to about 18mb to 19mb. That requires a pretty precise beam, and normal microwave is point-to-point technology, so we had to adopt a lot of changes to make the microwave path work for this kind of bandwidth. In the future, compression will be better and data streams will be smaller, so we will need less to transmit it, but this general engineering philosophy will still be the best way to do it.”

Alpaugh adds that the system's microwave technology relies on GPS and directional gyros to solve the tricky issue of locking the HD signal on a direct path to the receive site from a constantly moving and banking helicopter.

“A helicopter, unlike a remote truck, is constantly moving, so the narrow-beam microwave signal that works for a remote truck isn't enough for helicopter transmission,” Alpaugh says. “We needed an onboard technology to keep the antenna mounted in a circular pod under the aircraft, also able to rotate 360 degrees and moving the signal through a slip-ring. The pod needs to know where the receive site is and where the helicopter is at the same time. That is accomplished generally through GPS technology, but, since the nose of the helicopter is always moving, the computer system controlling the transmission also needs to know where the nose of the helicopter is at all times.

“That's why we depend so heavily on directional gyros on board,” Alpaugh explains. “They help us calibrate exactly where the nose of the copter is pointing, even when the helicopter is banking, and it takes telemetry from the GPS system, compensates for the movement of the helicopter, and calibrates where the mountain-top receive site is. So in other words, the gyros keep our antenna constantly pointed toward the chosen receive site.

“The system also has tilt capability, which is a fairly new technology. It allows the antenna to not only move 360 degrees, but also to tilt 45 degrees, plus or minus. That lets us concentrate the beam even better.”

The WNYW SkyFox helicopter also includes a SkyLink HD transmission antenna system from Troll Systems, with a C100 control head, which controls the antenna and the onboard ENG transmitter and receiver.

On the ground

Of course, that's only the beginning of the story. WNYW had to incorporate major system changes in terms of receive stations and master control approaches to acquire, manipulate, and air the HD signal for both HD and SD broadcast, usually simultaneously.

Shjarback explains that WNYW made numerous decisions about how best to interface the new system with the station's existing infrastructure. “That includes everything from our production switcher, master control, remote receive sites, and just understanding how to transport the HD signal around, especially since we are continuing to evolve from SD to HD, and many of the devices we needed to deploy are not exactly plug-and-play.

“The lesson we learned,” Shjarback continues, “is that there are subtle differences between encoder, decoder, and transmission equipment manufacturers, and how each treats the transport stream. For instance, we found areas where a decoder and a format translation device were not compatible or compliant, and you end up not being able to reliably decode the signal.

”This is where field testing prior to purchase really pays off. Manufacturers are generally more than willing to work with you in these areas, since it will provide valuable feedback for future sales and products. Other questions you need to answer are, do you bring [the signal] back from the receive site over microwave or phone lines? And where do you decode — at master control or production control? Basically, we learned that nothing is standard, even when someone tells you it is, and no one person has all the answers.”

Shjarback emphasizes that during this process, WNYW decided for now to upgrade only its main receive site in the New York City area for HD signal processing. That upgrade included HD/SD conversion equipment and new transmission equipment to send the signal forward to master control, along with HD switchers, HD logo inserters, and format converters.

“That was more than sufficient for the state of HD broadcast right now,” Shjarback says. “We upgraded [the main receive site], since it receives most of our shots from the helicopter, covering the majority of the metropolitan area. Some systems were already digitally capable at the main site, and for those we added a [Tiernan TDR6] HD decoder. In testing, we also learned it can be difficult to keep an HD signal locked as the helicopter is moving, so we initiated new auto-tracking software in our remote [antenna] control system. We chose MC5 remote control software from NSI [N Systems Inc. of Columbia, Md.] to operate our [NSI Superquad 2/7] receive antenna. It's working great for our current needs.”

WNYW, however, unlike many stations, has its news control room in a separate location from its master control room — one is in New York City and the other in New Jersey. This created additional considerations for the station as it set out to integrate this transmission approach with its existing SD switching system.

“By taking the signal to master control, we took some flexibility away from our news control room, but it allowed us to have a simpler way to integrate this new system into our existing operation, and later allow us to build on that,” Shjarback says. “So we route the signal from the transmitter to master control in New Jersey, bypassing the news control room altogether. When the HD signal goes on the air, by pressing a button in New York, it tells another controller in New Jersey to switch over to the HD feed that comes directly from our receive site, and we put that straight into our digital transmitter. In a best-world application, we would convert the entire news control room to HD, and it would take in the signal as any other source. But that option is a little further down the road, and one that will require a more significant fiscal commitment.”

At its master control facility, WNYW added an Evertz X-0401H-AES4 HD switcher, an Evertz 7710XC-AES4-HD crossconverter, an Evertz HD9625LG logo inserter, a Tiernan TDR6 HD decoder, and a NuComm VR-AFMT-CT analog coder.

These were among a myriad of component choices made by the engineering team at WNYW, part of a larger, ongoing conversion that will require further changes and upgrades in the coming months and years. But KUSA's Don Perez advises station engineers to look at the process as a total system.

“You have to do system analysis to make this work,” Perez says. “To go to HD, it is more revolutionary than evolutionary, and so you have to look at it as an overall system from a technology perspective — even though you are getting components from multiple manufacturers — and from a workflow perspective. You are creating a 16:9 product, after all, but right now the majority of your viewers will watch it in the 4:3 aspect ratio. From that point of view, [as an engineer], you have two sets of customers and two different criteria. So you need to build a system that deals with that reality, and looks at not only the technology, but also the workflow issues that have to be dealt with.”

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