The digital convention
CBS Newspath introduces its new MCPC platform for the GOP's Philly party
By Peter J. Brown -- Broadcasting & Cable, 7/30/2000 8:00:00 PM
At this year's Republican National Convention in Philadelphia, CBS Newspath began testing its affiliate news service, according to Executive Director of Affiliate Services Mel Olinsky, who oversees the network. As the news organization that has been pushing the envelope of digital satellite newsgathering (DSNG), Newspath has added a whole new twist to its political convention coverage.
For the first time, CBS Newspath will be using its new multichannel-per-carrier (MCPC) platform instead of a single-channel-per-carrier (SCPC) platform. This will allow for the broadcast of 15 separate feeds to its O & Os and affiliates using a single transponder on Loral Skynet's Telsat 6 satellite.
With SCPC, says Olinsky, a single carrier is transmitted with one video/ audio signal from an uplink. Thus, it is possible to have as many as 10 trucks in various locations around the country sharing one transponder. In MCPC mode, however, one carrier is transmitted, which can contain as many as 15 channels of video/audio, although it must originate from the same location.
"That is the one drawback to using an MCPC platform. Everything has to originate out of one location," he says, although it does not pose a problem for convention coverage.
An SNG truck from CBS O & O KTVT-TV Dallas, equipped with both primary and backup 300-watt amps from MCL, will serve as the uplink vehicle in Philadelphia and, two weeks later, at the Democratic National Convention in Los Angeles.
"We are feeding 70-MHz IF [intermediate frequency] to the upconverter and the HPA [high-powered amplifier] and bypassing everything else in the truck," Olinsky explains.
Not only does the switch from a single-channel-per-carrier satellite transmission to an MCPC solution reduce costs because the number of channels on a transponder can be doubled, but it also eases the top-of the-hour-scheduling logjam that frequently occurs with special-event coverage such as a political convention.
"We do four-minute windows," he says. "With this new MCPC platform, we can easily stack up the live feeds to 30 different stations in the first eight minutes at the top of the hour."
A Codico E-1100, a DVB encoder that supports 4:2:0 MP (main profile) at ML (main level) from Israel-based Tadiran Scopus Ltd., lies at the heart of this MCPC platform, along with a Codico RTM-3600 multiplexer/remultiplexer. The Codico IRD-2520 receivers are deployed at CBS Newspath receive sites. The data rate will range between 3.5 Mb/s and 6 Mb/s, depending on the nature of the coverage. Olinsky notes that 4:2:0 simply uses a lot less overhead when data rates under 7 Mb/s are employed.
"Our full-time news feed-24/ seven-has been all digital for exactly one year," he says. "We provided Ku-band satellite dishes and IRDs [integrated receiver descramblers] for every CBS affiliate for this project. And so all CBS affiliates are now capable of receiving DSNG."
Approximately half of CBS Newspath's affiliate fleet of 90 trucks are digital, and all 12 regional offices are equipped with digital fixed uplinks. An additional network of 85 fixed uplinks will be upgraded to digital soon.
"We are currently using a data rate of 7 Mb/s, but we will be decreasing that in September to allow 10 SCPC channels in a 54-MHz transponder," Olinsky says. "We have been testing this scheme at one of our affiliates in Texas, and the performance has been excellent."
CBS Newspath no longer uses a fiber feed to the Group W uplink facility in Stamford, Conn. Instead, direct Ku-band access to both Telstar 6 and GE-5 is available from a rooftop uplink facility at CBS headquarters in New York. CBS Newspath uses two transponders on Telstar 6 and one on GE-5.
"One and a half of the transponders on T6 are digital all the time," Olinsky says, "and the rest varies depending on demand. At full capacity or in an all-digital mode, we will be able to accommodate 30 digital carriers on our own capacity."
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