Television stations can successfully share the same digital channel, according to a new report on a recent channel-sharing experiment designed to help broadcasters decide whether to sell airwaves during an upcoming auction.
Two Los Angeles-area television stations recently agreed to help the wireless industry test the feasibility and limitations of channel sharing. KLCS-TV, a Public Broadcasting Service station in Los Angeles, and KJLA, a Spanish-language affiliate of the LATV Network, agreed to participate in the trial.
Federal Communications Commission officials want broadcasters to give up some or all of their airwaves for an upcoming auction in exchange for an undetermined payment from the government. If they can find a local partner, they could potentially air their programs on digital streams using the same channel.
The auction is voluntary – broadcasters don’t have to participate.
The two LA stations found that it was possible for two stations to combine their video streams and continue to broadcast without viewers seeing any difference, according to the report.
Since TV broadcasts are now all-digital, it’s possible for TV stations to squish multiple channels into the space they once needed to air one channel. Many local stations now air a combination of high-definition and standard-definition channels.
In the test, the Los Angeles broadcast engineers tested a variety of scenarios for how they might be able to combine their HD or standard-definition streams into one channel without affecting the quality of their TV programming. They found it was technically feasible to combine two HD streams into one channel along with a couple of standard-definition streams.
Such combinations might not work for every station, depending on the type of programs they air, said Alan Popkin, KLCS’s director of engineering and technical operations. The LA broadcast engineers found that using newer compression technologies allowed them to successfully air more streams in the same channel space.
While the tests suggested broadcasters could share channels using various combinations of HD and standard-definition streams, it’s still a scary possibility for station owners who aren’t sure if such sharing will keep them on the air.
“We’re looking at, ‘Can we participate in the auction and maintain our channel count?’” Popkin said. “You can’t guess at this. You need to know, because it’s a one-time-only auction. If you’re wrong, you can’t get [the channel] back.”
The study is part of a lobbying campaign by CTIA, the wireless industry’s lobbying arm, to convince TV stations to sell or share their airwaves.
Wireless carriers need a few broadcasters in the top 30 markets in the U.S. to give up some or all of their TV channels for an upcoming airwaves auction. The Federal Communications Commission is planning to hold a two-sided auction next year during which it will simultaneously buy airwaves licenses from TV station owners and sell them to wireless companies for LTE wireless broadband use.
The auction process is fraught with uncertainty right now because it’s not clear yet if enough station owners will be willing to part with their airwaves. FCC Chairman Tom Wheeler is expected to unveil proposed rules for the so-called 600 MHz auction, including details about the size of licenses that wireless companies will be able to acquire, within the next few weeks.