Phil Kurz /
02.01.2008
Originally featured on BroadcastEngineering.com
The DTV dance

About one year from now, the day the television industry, federal regulators, the U.S. Treasury, emergency first responders and spectrum-hungry wireless telecommunications companies have long-awaited is due to arrive.

On Feb. 17, 2009, full-power television stations in the United States will discontinue analog television transmission, consolidate onto a narrower swath of the spectrum allotted for television and free up channels 52 through 69, clearing the way for a massive spectrum auction that will generate billions in revenue for the U.S. Treasury, as well as advancing the goal of establishing an interoperable wireless communications system for police, firefighters and other emergency first responders.

To pull this off, hundreds of television stations across the country will vacate temporary DTV channel assignments and reclaim their existing analog channel assignment for digital operations. Others will move to new digital channels, giving up their current DTV assignment, as well as their analog service. About 65 percent of the 1812 stations that will broadcast DTV following the transition will stay on their current digital channel assignment, maximize power and relinquish their analog channel assignment.

Looked at another way, this DTV spectrum dance means 600 television stations will partake in what the Association for Maximum Service Television has dubbed “significant channel movement” next February.

Last March, the FCC, the NAB, the Association of Public Television Stations and MSTV shifted into high gear to spell out for television stations the scope of the task that lay ahead and to build a sense of urgency among the TV engineering and management community about getting it done. Kicking off the final push was a joint webcast for the television community in which the industry groups and the agency illustrated how the daisy-chained channel swaps could produce harmful interference to stations in the same service area and nearby markets if steps were not taken to coordinate this dance into the digital broadcasting era. To pull off the transition without a hitch, individual stations could not simply decide for themselves when to move, but rather needed to recognize that they may need to wait for another station in their service area or adjacent market to move first.

The other message the group conveyed was that stations could no longer delay purchasing their ticket to this elaborate digital dance. Orders for transmitters, antennas, and waveguide and tower rigging services needed to be expedited because of finite production capacity and a limited number of tower crews.

Within weeks of the event, MSTV president David Donovan was finalizing plans for a nationwide tour last summer to meet with local broadcasters and deliver those key messages face to face. Rather than finding stations behind the curve in their preparations, Donovan discovered the situation was far better than he'd imagined.

“I have been to many states over the summer, and I was pleasantly surprised by the number of stations that had actually taken the initiative, understood and were really moving the process,” he says.

While acknowledging some had not, the vast majority were diligently preparing, he says.

From what he observed, stations also were aware of and pursuing the coordination needed for a successful transition.

“I think the message has gotten out among the stations that if you are changing channels, your ability to do that may depend on another station,” Donovan says. “For the most part, the stations have been in discussions so that they know who they have to coordinate with. A year ago, I wanted to make sure these guys understood the daisy-chain pieces, and it's clear to me now that they do.”

Third Periodic Review

In December, the FCC approved its Third Periodic Review on the DTV transition in which it approved adjustments to its policies and rules to give broadcasters more flexibility in completing their transition. The commission also set up two interim deadlines before February 2009 for broadcasters to file progress reports on the build-out of their digital facilities. With the reports due in February and October, the commission hopes to make any adjustments necessary to hit the statutory deadline.

At the time of the commission's review, more than 800 stations had completed construction of their digital broadcast facilities and were ready to transmit on their final channel assignment. According to Donovan, last summer he found that many of the stations waiting to proceed were delaying until the commission had completed its work on the review.

To provide the flexibility stations will need, the commission plans to rely on the waiver process. While pleased that the commission acted, Donovan says reliance on waivers has the potential to delay progress.

“I think one of the great unknowns is because everything is now going to be done by waiver, a station still won't know until the commission makes a decision,” he says. “In other words, not all of this is just black and white.”

Of particular concern are the rules related to stations wishing to migrate their digital transmission back to their existing analog antenna.

“If the commission says, ‘Yes, fine,’ but if they say, ‘No,’ you are going to have to go out there and get a top-mount digital antenna fairly quickly,” Donovan says. “Then the question is if you can put it up in the winter.”

Commissioner Jonathan Adelstein, commenting on the periodic review, acknowledges that the commission had “lost valuable time” working on “more tangential aspects of the transition” rather than “clarifying urgent demands on broadcasters to get a huge job done in short order.” He too cited winter as a major concern because “important technical work on towers and antennae cannot be accomplished” in much of the country because of inclement weather.

While individual stations will work diligently to overcome these and other obstacles before Feb. 17, 2009, focusing only on what each station must accomplish or even the DTV spectrum dance doesn't fully portray the enormity of what must happen within the next year.

In commenting on the review, commissioner Michael Copps suggests a more expeditious process not only would have given broadcasters time to complete their build-out, but also allow adequate time to conduct trial runs in limited areas to discover and iron out unanticipated problems.

“Pulling the switch on stations all across the land at once and the same time in February 2009 is going to be a real throw of the dice,” he says. “It is unfathomable to me that we are planning to turn off every full-power analog signal in the country on a single day without running at least one test market first.”

Regardless, the Congressionally mandated deadline leaves no wiggle room. Short of a change in the law, the DTV transition of full-power TV will go ahead as planned. While broadcasters will work to make that painless for viewers, Copps is not so sure the public won't experience problems.

“Not every consumer will have access to all of their analog broadcast channels on Feb. 17, 2009, and then wake up happily the next morning to those same stations in digital,” Copps said in comments released after approval of the review. “There will be some period of time — perhaps before the transition date and almost certainly after — in which some stations may not be able to provide service to all of their viewers.”

If the commissioner's pessimistic view comes to pass, however, it won't be for lack of effort on the part of the nation's broadcast community.

Phil Kurz authors several Broadcast Engineering e-newsletters, including “RF Update.”

Open Mobile Video Coalition to conduct consumer trials

The coalition formed to promote development of an ATSC-compatible transmission system that will let television broadcasters transmit directly to viewers on the go announced last month it will conduct consumer trials of two competing technologies this year.

The Open Mobile Video Coalition (OMVC) plans to test Mobile-Pedestrian-Handheld (MPH), jointly developed by LG Electronics and Harris, and A-VSB, developed by Samsung Electronics and Rohde & Schwarz, to learn additional technical details about the systems and to gauge consumer acceptance, behavior and preferences.

Unlike video content distribution via wireless telecom providers, both MPH and A-VSB offer broadcasters a means to exert direct control over mobile content distribution and will allow them to develop business models based specifically on their own interests.

OMVC and the leaders of each set of trials will select several test markets. A sample of consumers will be chosen to receive and test mobile video content that will be broadcast to mobile and portable receiver devices, such as cell phones, personal media players and laptop computers.

Consumer test participants will be able to watch a selection of local and national content and access interactive services. Usage will be tracked to monitor and better understand consumer preferences. At the end of the trial, the OMVC and its partners will be able to predict consumer usage patterns and system performance to support the launch of mobile digital television services targeted for 2009.

Certain broadcasters among the 800 OMVC member stations will be selected to provide the transmission infrastructure and local content for the trials in each market. As one of the content sources for the OMVC's consumer trials, SES AMERICOM will provide mobile broadcast network platform services and aggregate and distribute national content via its IP-PRIME satellite service.

In MPH trial markets, Harris will provide MPH in-band digital television transmission equipment, and LG Electronics will provide MPH consumer receiver devices. In A-VSB trial markets, Samsung's partner, Rohde & Schwarz, will provide transmission equipment based on the A-VSB in-band mobile digital television system, and Samsung will provide A-VSB consumer devices.

FCC kicks off ‘Phase II’ white space device testing

The FCC's Office of Engineering and Technology (OET) kicked off second-round testing of prototype personal/portable TV white space devices as part of the commission's proceeding examining their authorization. Central to the tests, as well as the issue of whether or not the white space devices can coexist with DTV stations, is their ability to sense the presence of television transmissions and select a channel for operation that will not create co-channel or adjacent channel interference.

Initial OET test results released in July 2007 found the prototypes submitted for evaluation generally failed to detect the presence of DTV transmissions as well as that of Part 74 wireless mics, which share the TV band.

The OET is conducting the current round in two parts, lab and field testing. Both sets are open to interested parties, and each is expected to take four to six weeks to complete. After compiling and analyzing the results, the OET's findings will become part of the record in the commission's proceedings on the matter. The commission recently received several prototypes for this round of testing, including devices from Adaptrum, Microsoft, Motorola and Philips.

The issue of allowing unlicensed wireless devices to operate in the DTV band has been highly contentious. Broadcast groups such as the NAB and Association for Maximum Service Television point out that the sensing technology has never been proven to work. They fear that without absolute certainty that the devices will detect DTV transmission, any authorization to allow them to reach consumers would create wide-scale harmful interference to DTV reception and essentially squander the billions of dollars already spent by consumers and the television industry on the DTV transition.

On the other side of the issue are groups like the Wireless Innovation Alliance (WIA), consisting of prominent high-tech companies. The WIA contends TV spectrum is underused and can be harnessed for new applications for consumers, students and emergency personnel.

DTV derailment?

Under the program that grants households up to two $40 coupons towards the purchase of approved digital-to-analog converters for use with NTSC TV sets, not a single one has an NTSC tuner, and only a handful have the ability to pass an NTSC signal through to a set. Designed to the specifications of the National Telecommunications & Information Administration, these converter boxes have been regarded as the silver bullet that will prevent over-the-air viewers who don't buy a new DTV set from becoming disenfranchised when full-power stations turn off their analog transmitters next year.

However, without an NTSC tuner in the converter, viewers who exchange a government-issued coupon for a converter and connect it to their TVs and antennas will simply find that many of the stations they're accustomed to viewing will go away. If they take the trouble to disconnect the converter and once again connect their antenna to their set, those stations will magically reappear.

A cursory look at the FCC database of TV station licensees by market reveals that within about a 50-mile radius of the top 10 Nielsen DMAs, there are no fewer than 64 analog LPTV, Class A and translator stations. For community broadcasters, who rely nearly exclusively on an audience that depends on off-air reception, the situation is intolerable.

“Distribution of the boxes, in our opinion, may well be illegal,” says Greg Herman, Community Broadcasters Association (CBA) VP of technology and owner of WatchTV, a Portland, OR, low-power television broadcaster.

The CBA contends the All Channel Receiver Act requires all television receivers to receive all television channels allocated to broadcasting.

“When the FCC ordered television and TV device manufacturers to include digital tuners in all of their devices, it said that reception of all channels means not only channels 2 through 69, but all of the stations that are broadcast on those channels,” says association legal counsel Peter Tannenwald.

While the act doesn't spell out that analog tuners are required, Tannenwald contends that to be logically consistent, NTSC tuners are necessary.

“The thing that the FCC has explicitly stated is to receive all channels during the transition, you must have a digital tuner,” Tannenwald says. “It's my application of that logic to say that if you receive all channels during the transition, you must have an analog tuner as well.”

At issue is interpretation of the Deficit Reduction Act of 2005 that defined the characteristics of the type of converter that would be authorized for coupons. The NTIA has interpreted the act to mean that a converter can only have the ability to receive ATSC digital television signals and make them available to an analog television.

On Jan. 25, the FCC met with Herman and other representatives of the association to discuss how to proceed. With the first converter boxes expected on retailers' shelves in mid-February, the meeting took on added urgency.

According to Herman, the CBA sought six things:

  • a requirement for all converter boxes produced after those initially shipped to include an NTSC tuner;

  • a label on those first converter boxes to warn consumers that they will block reception of some federally licensed television stations;

  • point-of-purchase displays at retailers with the same warning;

  • the right for consumers to return the initial boxes without penalty for converter boxes with analog tuners;

  • an extension of the NTIA coupon program to six months; and

  • a redirected DTV public education effort to inform Americans that only a minority of all TV stations will make the digital conversion in February 2009.

“We have never desired to shut down the digital transition; we just want to make it fair,” Herman says.



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