Total RF Doubles Up on Technology for First Marathon in 1080i

Total RF and CP Communications have supported the broadcasts of multiple marathons in SD and some in partial HD, but, until last weekend, the companies had never successfully broadcast a marathon in full HD. At the 2010 Chicago Marathon, however, Total RF combined two technologies to build a system that produced the first 1080i HD coverage of a major marathon in the U.S.

“In today’s day and age, you can’t stick with just one technology,” explains Kurt Heitmann, president of Total RF and SVP of CP Communications. “In our case, multiple technologies come together for a successful HD Chicago marathon. We worked for a year and designed this system using GigaWave’s antenna infrastructure and Link Research’s encoding and decoding.”

Motors (With Cameras) Running
That system relied on feeds from three on-course vehicles, provided by Heitmann’s team, and a total of 12 HD cameras. The lead vehicle was a truck fitted with a specialized Cineflex gyro-stabilized HD camera, designed by his team. The lead men’s and women’s motorcycles were outfitted with Panasonic HD cameras, and two wireless Grass Valley LDK 8000 cameras covered the start line. Seven ENG inbound feeds were also received from WMAQ Chicago, the local NBC affiliate, from the station’s ENG vans covering the action throughout Chicago’s neighborhoods.

“WMAQ converted everything to HD this year,” Heitmann says. “We muxed those feeds down to two fiber paths using EuroTech muxes, decoded them at our finish-line truck, which was our RF HD5 unit, and then passed them off to WMAQ.”

Hancock Handoff
To use the wireless signals from the three on-course vehicles, receive sites were placed on Willis Tower (formerly Sears Tower) and Hancock Center. A six-antenna array on Hancock, split among three receivers, handled the coverage from the start line through mile 11. The Chicago Marathon has a mass start, and, although the men outpace the women, for the first 11 miles, the same antennas can be used for the lead vehicles on both races.

“We received all of the signals from the three vehicles on the north side of Chicago from Hancock,” Heitmann explains. “We would take the ASI streams out of the receivers and mux them and then send that over to Sears. Sears would then send it down to our truck.”

The first few miles of the race take runners through the north end of Chicago, where tree-lined areas are beautiful to run through but can cause issues for RF reception. In the past, the coverage has been spotty in those regions; this year, Heitmann says, the coverage was nearly flawless.

“We really focused on being able to track the vehicles,” he says. “In years past, we didn’t have GPS up on the roof, so we added GPS tracking this year. The rooftop trackers had GPS this year so they knew exactly where the vehicles were and could really focus their antennas on them. The coverage was phenomenal.”

A Clear View From the Sears Tower
From mile 11 to the finish, a 16-antenna, three-receiver system on the Sears Tower covered the race. In the final miles, the growing gap between the men’s and women’s races requires that different antennas track the lead vehicles.

“We would switch antennas on Sears based on our coverage needs and where the vehicles were,” Heitmann explains. “We track all of the vehicles with GPS and spectrum analyzers to look at the signal level. On Hancock, we did not have as much of an antenna-array system because the men and women are pretty much together for the first few miles. But once you get to mile 11, your separation is getting substantial, and you have to be able to switch your antenna systems.”

The process for getting the signal to the truck from the Sears receive sites was identical to the process from Hancock: the ASI stream was taken out, muxed down to the RF HD5 truck, and sent to WMAQ.

“In the truck, we are monitoring all of those streams, decoding the video, and looking at which site has the best coverage,” Heitmann says. “We switched the ASI into our final decoders, which are then going to WMAQ. We were doing ASI switching in the truck and antenna switching on the rooftops, and we ended up with 98% flawless coverage of the entire course, running in 1080i.”

Twice as Nice
In 2009, Heitmann’s team deployed GigaWave technology alone, running at a high bitrate, to achieve an HD broadcast, and was unsuccessful.

“This year, we went with two different technologies,” Heitmann explains. “We used Link Research L1500 encoders and encoded that at 9 Mbps at a QPSK modulation stream. Then, we put that into stealth amplifiers that we custom-built on our motorcycles. That was received by RF Extreme receivers and GigaWave decoders for monitoring, and the final product was decoded at the truck with Link Research decoders.

“Link’s encoding is more forgiving,” he adds. “They’re able to encode a beautiful HD signal at 9 Mbps and can still have the throughput that you need to do a marathon.”

Adding the Link Research encoders and decoders to the GigaWave antenna infrastructure that Heitmann’s team already used proved to be the missing link in a successful 1080i HD major marathon broadcast.

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