Chicago’s WBBM-TV unifies Shure RF microphones

Before the FCC’s order to vacate the 700MHz band became a reality in June, WBBM TV-2 Chicago, a CBS owned-and-operated station, hired TC Furlong, a professional audio firm in suburban Lake Forest, to evaluate its wireless situation and recommend solutions.

With IFB (interruptible foldback) and wireless microphone systems affected by the change, the challenge was to expand the station’s wireless capabilities beyond Studio A, the station’s street-level broadcast center, to include the third-floor newsroom and Daley Plaza, located just outside the studio in downtown Chicago.

The newsroom is a large, L-shaped office area where all the anchors, news directors and dispatch people work. The station uses live newsroom shots for segment previews and breaking news reports. Previously, those shots did not include audio.

Beyond the 700MHz issue, the station wanted to create a full intercommunications system so the talent could be called over IFB and respond on their lavaliere mic. To do that, they needed a unified antenna distribution system that would cover both wireless mics and IFB across all these spaces.

The specification was for 12 RF mics and eight IFB channels. To handle the microphone system, the firm recommended Shure’s UHF-R wireless line. It prepared frequency coordination and saw Shure’s G1 band had plenty of available frequencies, even in downtown Chicago.

The antenna systems are run through splitters, providing A/B diversity feeds from Studio A and the third-floor newsroom, which are then routed to the UHF-R wireless mic systems, racked together in Studio A, and a similar multiple antenna system for the IFB transmitters, located in a second floor equipment room. This necessitated cable runs of up to 300ft, accommodated by using LMR600 low-loss, solid core cable in combination with in-line signal amplifiers.

The six dual-channel Shure UR4D receivers accept their signals from two UA845SWB (super wideband) antenna splitters, while the IFB system uses a Shure PA821SWB 8-to-1 combiner and a Model 5624 splitter from Professional Wireless Systems. The two systems are fed by five Shure HA8089 helical antennas, augmented by a circularly polarized antenna, each with a high-pass/low-pass filter set in-line. To ensure proper signal level, two Shure UA830WB in-line antenna amplifiers add a 3dB boost en route to the splitters.