WTTW Goes All the Way

Chicago's PBS station opts for all-new facility for digital transition


Facing the digital transition in a 35-year-old facility, the board of directors for PBS affiliate WTTW in Chicago figured it was time for new digs. That was nearly three years ago. On Sept. 15, WTTW unveiled the fruit of the board's decision -- a brand new digital broadcasting facility stocked with state-of-the-art, HD-ready equipment.

Two-and-a-half years in planning and construction, the digital broadcast operations center takes the station "to the highest level of digital broadcasting technology," said Dan Schmidt, WTTW president and CEO.

Fred Engel, WTTW's director of engineering operations, maintenance and design, said the complete overhaul "gave us an opportunity to build a new facility with the new equipment and not have to worry about trying to adapt an old facility... To start with a clean sheet of paper was a lot easier process for us."

WTTW first turned to the architectural design firm of Harold Lutz and Associates to create the building and to interior design firm Studio Design Group to lay out the inside. The final result includes a high-ceilinged, glassed-in 1,600-square-foot operations room and a 400-square-foot room for the server and switcher farm. WTTW's role as an educational broadcaster factored into the design. The building's glass-walled operations room was conceived as a viewing area for visiting schoolchildren, donors and foundations.

"We wanted to be able to say 'Here's our facility, this is what it looks like, this is how we make television,'" said Engel. "People can come in and observe how a TV station works without interrupting the work."

Even before WTTW moved to its new operations center, the station's transition from analog to digital was taking place in stages. Field acquisition work went fully digital back in 2001, and transmission has been digital since 2002.

As WTTW made its way through the conversion, the ever-changing technological landscape boosted the scope and capabilities of the new center.

"Probably the biggest shift we made was in our video server choice," said Engel. "We had anticipated buying a much smaller capacity server, but the cost of storage dropped, the speed of processors improved tremendously, and overall cost declined." As a result, Engel noted, "we were able to end up buying a much, much larger server than we anticipated."

The heart of WTTW's digital operations center is a SeaChange Broadcast Media Cluster five-node server with 80 hard drives, each with 180 GB of capacity, for total storage space of 14.4 terabytes. The 80 hard drives are divided among the five server nodes in a clustered arrangement designed to provide a high level of fault tolerance and redundancy. In addition to 11 standard-definition digital inputs and 15 outputs, the BMC also allows recording and playout of HD programming.


The choice of the SeaChange server was simply based on "dollars per gigabyte storage, dollars per hour," said Engel.

The server's 1,800 hours of standard digital storage is especially useful for WTTW, since half the station's weekday programming is children's educational shows.

"We found we could store all of our children's programs in the server," said Engel.

Having 60 to 100 episodes of oft-repeated daytime programming stored in the server is a big logistical bonus for the station.

Driving the SeaChange server is a Fastbreak automation system from Sundance Digital Systems that allows multichannel recording and playback. The Myers Information Systems ProTrack records traffic and play logs to the server, helping to cut down keyboard entry workand subsequent chances for error. Thomson's Trinix, Venus, Jupiter, and Saturn systems handle video and audio routing, router control and master control switching. Forty-seven miles of Belden video and Gepco audio wire keep more than 5,000 video and 50,000 audio paths connected.

In-house production work is still analog, but the plan is to shoot for tapeless within the next 18 months. Even so, and like many other nonlinear facilities, WTTW won't completely abandon its tape capabilities. Sony BetaSX tape machines will be employed for SD needs; Sony's HDCam tape machines will cover high-def.

WTTW's "digital glue" conversion products include Ross Video converters and distribution amplifiers, Leitch distribution products, and standard- and high-definition and close-captioning equipment from Evertz. A Miranda Kaleido K2 virtual monitor wall system drives two 60-inch Zenith HD plasma displays for program monitoring, while two more 60-inchers are used for on- and off-air cable display.

WTTW delivers its signal via MRC's Twin Stream system atop the 1,450-foot Sears Tower, where the station's Harris Sigma UHF transmitter is housed on the 100th floor and its new Andrew digital antenna is mounted on the roof. From there, WTTW beams two digital streams into the Chicago market: An HD stream and a copy of its analog transmission. The station's ultimate digital goal is to go all HD. Currently, WTTW's HD origination consists of its musical performance show "Soundstage," which is edited, produced and transmitted in HD.