The Londen Media studio in Phoenix produces live shows and taped events, and oversees control of the three cameras from KTAR-AM.
The Londen Media Group, located in Phoenix, approached Burst at the end of 2001 with plans to purchase KUSK-TV in Prescott, AZ, rebuild the facility and rename it KAZ-TV. The Londen Media Group wanted to transfer the broadcast signal to the Phoenix market in high-quality digital instead of picking off the signal using an antenna from a number of tired translators. This is not terribly difficult, but they also wanted to pull live content from a new production facility and local AM radio station in Phoenix, KTAR-AM. The content needed to be delivered to Prescott (since that is the main city of license) and back to the Phoenix market via the COX cable system. In addition, the Londen Media Group required a connection to receive sporting events from the University of Arizona and Arizona State University.
Burst began the design by focusing its efforts in Prescott, where the master control foundation would have to be built. This would become the backbone for final program delivery. All of the other elements would eventually feed into the Prescott master control room.
The Leitch Opus and Sundance automation are the key ingredients of the master control console for KAZ-TV in Prescott, AZ. This control room utilizes an embedded SDI infrastructure.
They decided that an embedded SDI signal platform offered the most overall flexibility for a plant infrastructure and future considerations. They selected Leitch equipment to accomplish the task, including the Opus master control switcher, VR-440 servers, Digibus and the Integrator routing system. They selected the systems because they offered a high degree of interoperability. Sundance Automation was a logical choice for automation, along with the Panasonic DVCPRO50 tape format. Burst also needed to replace three consumer-grade satellite TVRO antennas, so they brought in Superior Satellite to handle the integration of three new 4.5m dishes that were outfitted with computer controls for the automation system to steer and control. They also found it necessary to build up the electrical plant. They found a used generator to beef up the emergency electrical needs along with new power distribution. Then came the hard part of determining how to transport the signal to Phoenix.
Figure 1. This MPEG-2 encoding/decoding scheme is featured in the master control center in Prescott, AZ, the CSG Telespectra microwave hub, the Londen Media Production Studios and the KTAR-AM morning show studios.
Londen Media selected CSG Telespectra in Phoenix as a distributor for a number of reasons. Namely, Telespectra could provide a robust DS-3 microwave infrastructure to and from Prescott and tie in the two sites (Londen Media Studios and KTAR-AM in Phoenix). It could also provide key deliveries to the COX headend and gather the sports feed for the University of Arizona and Arizona State University. But Burst was now facing some tough decisions on how to encode signals and deliver them through the DS-3 wireless topology.
An MPEG-2 compression scheme seemed in order. So, after a bit of research, Burst chose Scientific-Atlanta encoders. These boxes can compress the signals and transport them over standard G.703 topology that CSG Telespectra has set up. The only trouble encountered was that the CSG Telespectra network required DS-3 framing. Even though Burst didn’t have the exact M13 framing, it selected the G.754 framing standard. The layout, as shown in Figure 1, is rather unusual. The originating signal begins in Prescott, where it is delivered to the transmission chain as a G.703 packet (DS-3). It is then sent to two DS-3 radios. One radio goes to the transmitter site on North Mingus Mountain and the other goes to Phoenix via South Mingus Mountain.
KAZ-TV’s production studio in Phoenix consists of an SDI video and stereo analog infrastructure featuring Ross Synergy Series switching. The facility also features Ikegami cameras and Wohler monitoring equipment.
Since the primary signal was already encoded for DS-3 transmission, it made sense to make the STL the same. The Burst Group chose to put in a DS-3 Nucomm 7GHz STL link featuring their DS-3 modulator and demodulator. Now, the signal quality going to Phoenix would be the same as the signal quality at the transmitter site, resulting in perfect digital quality on both ends. The Phoenix signal is terminated at the Telespectra hub site in Phoenix, where it is sent on to the headend.
The Londen Media studios originate several live shows and post-produce most of their material. Whether it’s live or tape, it is sent to the Telespectra hub site and relayed back to Prescott to air or record, depending on the day’s log. The KTAR-AM morning show has three Panasonic cameras that are remote-controlled by the Londen Media studios and then sent on to Prescott. University sports feeds are switched at the hub and sent back to KAZ-TV in Prescott for sporting events.
Figure 2. End-to-end MPEG-2 digital delivery from Prescott to Phoenix and back. Additional delivery is available within the Phoenix metro area.
The MPEG encoding rate is set at 10Mb/s, allowing for high quality pictures and sound to all locations. Furthermore, there is enough bandwidth for 19.39Mb/s compressed HD transmissions in the future, along with more program channels out of Prescott. Scientific-Atlanta’s single-channel Pyxis and multichannel Polaris MkII MPEG encoders were chosen for their flexibility and performance, along with Stellar decoders. These boxes allowed the use of SDI, SDI-embedded, analog and even the ability to genlock the output signal in the same combination of signals. In the future, it will be possible to ride a separate SMPTE 310M stream by simply adding option cards – no need to supply new decoders.
The production control room in Prescott, AZ, uses both Sony and Panasonic VTRs.
In Prescott, the plant infrastructure is SDI-embedded, so the encoder there was fitted to the signal using the ROSA management software. However, at the hub in Phoenix, the plant is entirely analog, as was the case for the present Mingus Mountain transmitter site. Fortunately, it was no problem configuring the decoder to output analog signals at both of these locations. Should either of these two sites upgrade to SDI plants, it will simply be a matter of reconfiguring the Stellar decoders.
At the Londen Media studio in Phoenix, the plant was a hybrid using analog audio and SDI video. The Pyxis encoder was easily configured for this combination.
The KAZ-TV master control room features Leitch VR 440 video servers and the Integrator routing system, and Scientific-Atlanta MPEG-2 encoding gear.
The most complex site was the KTAR-AM site. All three cameras were SDI with one main analog program audio tagged to one of the cameras. The Polaris MkII was configured and, at the Londen Media studio receive site, all three Stellar decoders were genlocked and timed for the SDI production switcher. The analog audio was retrieved and sent to the analog mixing console. The goal was to transport these signals and maintain a lossless signal, and it was achieved – the signals at all locations maintained their pristine images and sound.
The Londen Media Group successfully implemented a number of cost-effective new technologies for this project. The Scientific-Atlanta encoders and decoders were important in distributing and maintaining signals that might be a challenge using more traditional, expensive equipment. The DS-3 distribution topology proved to be a key ingredient, and a close look at the components revealed a compelling argument for rethinking traditional analog microwave topology. It is certainly less expensive and will allow for signals originating from Prescott since only a fourth of the bandwidth has been utilized. There is certainly room for HDTV distribution and more standard-definition program channels.
Scott Barella is vice president of engineering of Burst.
|Design Team |
| Scott Barella, vice president of engineering |
| Tony Roccanova, engineering project manager |
| Pat Pintus, sales engineer |
|Londen Media Group: |
| Ron Bergamo, vice president and general manager of KAZ-TV |
| Rich Howe, KAZ-TV station manager |
|Equipment list |
| Integrator router |
| Opus master control switcher |
| VR-440 servers |
| Terminal equipment and conversion |
|Sundance automation |
|Scientific-Atlanta encoders and decoders |
|Burk transmitter controllers |
|Ross Synergy production switchers |
|Panasonic DVCPRO VTRs |
|ADC patch fields |
|Belden 1855A video cable |
|Canare BNCs |
|Ikegami monitoring |
|Wohler audio and video monitoring |
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