Long before the FCC’s order to vacate the 700MHz band became reality on June 12, WBBM TV-2 Chicago, a CBS owned-and-operated station, was deep into preparations. With both IFB and wireless microphone systems affected by the change, the station engaged TC Furlong, a full-service pro audio firm in suburban Lake Forest, IL, to evaluate the situation and recommend a solution.
The challenge was to expand the station’s wireless capabilities beyond Studio A, the street-level broadcast center for several daily newscasts, to include the third-floor newsroom and also the outdoor Daley Plaza, located just outside the studio in downtown Chicago. The newsroom, often called the bullpen, is a large, L-shaped office area where all the anchors, news directors and dispatch people work. During most newscasts, the station uses live shots from the bullpen for segment previews and breaking news reports. Prior to this installation, those newsroom shots did not have audio feeds. Finally, the station also wanted the ability to do outdoor live remotes from Daley Plaza, located just outside.
“Beyond the 700MHz issue, the station’s desire was to create a full intercommunications system, so the talent could be called over IFB and respond on their wireless mic,” said Jeff Cech, general manager at TC Furlong. “To do that, we needed an antenna distribution system that would cover both systems across all these spaces, making it one big system.”
The specification was for 12 channels of wireless microphones and eight IFB channels. To handle the microphone system, TC Furlong recommended Shure’s premium UHF-R line. “We prepared frequency coordination and saw that Shure’s G1 band had plenty of available frequencies, even in downtown Chicago,” said Scott Helmke, project manager for TC Furlong. “In fact, they even have a couple spare frequencies available in case the landscape changes.” Choosing Shure also gave WBBM the ability to exchange its old 700MHz Sony systems for significant cost savings, with access to a wide range of both handheld and body-pack miking options.
WBBM elected to stay with its Lectrosonics IFB systems but purchased new ones rather than having the existing units sent in for new frequencies. “Those systems are in use every day, and they weren’t prepared to rent temporary IFB systems during factory service,” Helmke said. “It also made sense to have all the equipment on hand for testing with the new antenna system we were designing.”
That unified double antenna system was a challenge because it would have to pick up everything seamlessly for both IFB and mics across both these spaces. Previously (like most stations), TV2 had no wireless mic coverage at all for its newsroom shots. Working with wireless guru James Stoffo, renowned as wireless coordinator for the Super Bowl and many other major events, the team created an antenna system based around a mix of antenna splitters and combiners, paired with various antennas. “The tricky part was that they couldn’t have separate transmitter or receiver systems in the two main rooms, because the talent actually moves between those spaces. We were very fortunate to work with James in creating a single, cohesive system,” Cech said. “Based on the frequencies involved and the configurations of the rooms, he recommended a mixture of different antenna types and locations that exceeded the client’s expectations.”
The antenna systems are run through splitters, providing diversity “A” and “B” feeds from both Studio A and the third-floor bullpen, which are then routed to both the Shure UHF-R mic systems, racked together in Studio A, and a similar multiple antenna system for the Lectrosonics T4 IFB transmitters, which reside in an equipment room on the second floor. This necessitated cable runs of up to 300ft between antennas and wireless systems, with the long runs accommodated by using LMR600 low-loss, solid-core cable in combination with inline signal amplifiers.
The six dual-channel Shure UR4D receivers accept their signals from two UA845SWB (super wideband) antenna splitters, while the Lectrosonics IFB system uses both a Shure PA821SWB eight-to-one combiner and a Model 5624 splitter from Professional Wireless Systems. The two systems are fed by a combination of five Shure HA8089 helical antennas and one Sennheiser A5000CP circularly polarized antenna, each with a high-pass/low-pass filter set inline. To ensure proper signal level, two Shure UA830WB inline antenna amplifiers add a 3dB boost en route to the splitters.
To get wireless reception from the third floor down to Studio A, two impedance-matching passive antenna splitters were used to combine the antennas on the first floor, and also those from the third floor, prior to the signal reaching the receiver. “We could only get away with that because the two spaces are so isolated from each other,” Helmke said. “So whatever transmitter is going to be picked up by an antenna in one space is going to be so greatly attenuated in the other space that there’s not really going to be a conflict.”
Each space use two antennas (for “A” and “B” diversity pickup), all of which are in constant use to create full, constant communication throughout both Studio A and the third-floor newsroom bullpen. “The only place we lose signal is when the talent gets in the elevator between floor,” Cech said, “and that’s primarily because it’s a Faraday Cage. As soon as you walk out of the elevator, the antenna system picks you up again.”
The last piece of the puzzle was to get coverage out in Daley Plaza, visible out the windows of both Studio A and the third-floor area. “They only really needed IFB coverage out there, since there are timing issues with using separate wireless mics with their digital cameras on remotes,” Helmke said. “So we aimed one of the Shure helical antennas (HA8089) out the window and walked the plaza to test the coverage.”
They team found they could cover the entire plaza from the third floor, while still maintaining coverage of the bullpen. “A large part of our success had to do with that Shure UA821SWB combiner, which is actually designed for use with Shure in-ear monitoring systems,” Helmke said. “That product turned out to be uniquely qualified for this application: first, because it’s a wideband system with eight inputs. But more importantly, it could also do power handling for the eight high-powered IFB transmitters, which transmit at 250mW.”
To make the antenna system as flexible and foolproof as possible, the TC Furlong team designed and fabricated custom antenna mounts able to handle the weight of the antennas and the heavy cables coming off them while still being flexible enough to be aimed as needed during installation. “Our goal was to get solid coverage in all the main areas all the time,” Helmke said, “and of course, since this is live broadcast, we did design some overkill into the system. That way, they can reconfigure the studio at will without the necessity of reaiming antennas. They do four or five daily live shows in that space, and everything they could reasonably foresee can be handled. The entire system is basically locked in place.”
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