DTV transition in the United States

See digital television transition for information on worldwide digital transition plans

The DTV transition in the United States (also called the broadcast digital transition) is the switchover from analog (the traditional method of transmitting television signals) to exclusively digital broadcasting of free over-the-air television programming. The transition from analog to digital television has been described by David Rehr, president and CEO of the National Association of Broadcasters, as representing "the most significant advancement of television technology since color TV was introduced.

Congressional mandate

All US full-power analog TV broadcasts will end in 2009. As of March 1, 2007, new television devices that receive signals over-the-air, including pocket sized portable televisions, personal computer video capture card tuners and some DVD recorders, have been required to include ATSC digital tuners. Currently, most U.S. broadcasters are beaming their signals in both analog and digital formats; a few are digital-only.

The transition from the analog NTSC format to the digital ATSC format will be completed on February 17, 2009, as set by Congress in the Digital Transition and Public Safety Act of 2005. Following the analog switch-off, the FCC will reallocate channels 52 through 69 (the lower half of the 700 MHz band) for other communications traffic, completing the reallocation of broadcast channels 52–69 that began in the late 1990s. These channels were auctioned off in early 2008, with the winning bidders to take possession of them in February 2009. Four channels from this portion of the broadcast spectrum (60, 61, 68, and 69) will be held for reallocation to public safety communications (such as police, fire, and emergency rescue). In addition, some of the freed up frequencies will be used for advanced commercial wireless services for consumers, such as Qualcomm's planned use of former UHF channel 55 for its MediaFLO service.

For U.S. cable television, the FCC voted 5-0 on September 12, 2007 to require operators to make local broadcasts available to their users, even those with analog television. This requirement lasts until 2012, when the FCC will review the case again.

Transition Testing

As part of a test by the FCC to iron out transition and reception concerns before the nationwide shutoff, on September 8, 2008, all of the major network stations in the Wilmington, North Carolina market ceased transmission of their analog signals and became the first market in the nation to go digital-only. Wilmington was chosen as the test city in part because the area's digital channel positions will remain unchanged after the transition. .

The test did not include any low-power broadcasters in the area except the low-power CBS affiliate WILM-LP, which will have a digital signal in time for the transition. It also excluded UNC-TV/PBS station WUNJ, which will keep their analog signal on as they are the official conduit of emergency information in the area.

Viewers were notified of the change by months of public service announcements, town hall meetings, and local news coverage. Only 7% of viewers were affected by the loss of analog broadcasts, the remainder subscribing to cable or satellite services, but this produced 1,800 calls to the FCC for assistance. Officials are concerned by this and look to larger markets or those where reliance on over the air broadcasts exceedes 30%.

On November 17, at 6:25pm, television stations in Erie, Johnstown, Altoona, Philadelphia, Pittsburgh, Harrisburg, Lancaster, York, Wilkes-Barre, and Scranton in Pennsylvania will suspend regular analog broadcasts for 60 seconds as part of a test. Some stations will leave viewers with a snowy screen, while others will put up a message informing viewers that if they can see the message they are not ready for the transition to digital television in February 2009. Similar tests were conducted in Milwaukee Wisconsin on September 15, 2008.

Impact of the transition

Digital TV uses a more efficient transmission technology that allows broadcast stations to offer improved picture and sound quality, as well as offer more programming options through multiple broadcast streams (multicasting). Television stations have been preparing for the transition from analog to DTV since the late 1990s, when they began building digital facilities and airing digital channels alongside regular analog broadcasts. Today, 1,609 out of 1,745 full power television stations nationwide offer digital programming, however, most of the smaller, low-power broadcasters, for whom switching to digital would be cost prohibitive, will still be permitted to transmit in analog for several years to come. Since the majority of US viewership is no longer using over-the-air antennae to receive signals, but has switched to cable and satellite, the impact will be much smaller on current NTSC receivers which will continue to use NTSC content and devices after the cut-off date. Set-top boxes will enable existing over-the-air NTSC only receivers to watch over-the-air ATSC signals.

A major concern is that the broadcast technology used to transmit ATSC signals called 8VSB has problems receiving signal inside buildings and in urban areas, largely due to multipath reception issues which cause annoying ghosting and fading on analog images, but can lead to intermittent signal or no reception at all on ATSC programs.. DTV broadcasts exhibit a digital cliff effect, by which viewers will receive either a perfect signal or no signal at all with little or no middle ground. Digital transmissions do contain additional data bits to provide error correction for a finite number of bit errors; once signal quality degrades beyond that point, recovery of the original digital signal becomes impossible.

The maximum power for DTV broadcast classes is also substantially lower; one-fifth of the legal limits for the former full-power analog services. A hundred-kW analog station on channel 2-6 would therefore be faced with the choice of either lowering its power by 80% (to the twenty kilowatt limit of low-VHF DTV) or abandoning a channel which it occupied since the 1950s in order to transmit more signal power on the less-crowded UHF TV band. Unfortunately, the higher frequencies perform poorly in areas where signals must travel great distances and encounter significant terrestrial obstacles. Most stations in VHF-low (channels 2-6) across the country will not be returning to these frequencies. This will leave on about 40 stations on low-VHF, and the majority of these are in smaller markets with a few notable exceptions. Only The FCC has long discouraged the digital allocation on this VHF-low channels for several reasons: higher ambient noise, interference with FM radio, and larger antenna size required for these channels. Some antenna manufactures such as Channel Master are creating antennas for channels 7-51 which are more compact than their channel 2-51 counterpart since most consumers will not need those low-VHF channels.

The Consumer Electronics Association has set up a website called Antenna Web to identify means to provide the correct signal reception to over-the-air viewers. The TV Fool website provides geographic mapping and signal data to allow viewers to estimate the number of channels which will be gained or lost as a result of digital transition; while it estimates that marginally more stations will be gained than lost by viewers, this varies widely with viewers of low-VHF analog signals in distant-fringe areas among the most adversely affected. An estimated 1.8 million people will lose the ability to access over-the-air TV entirely as a result of the digital transition.

A Google sponsored program called Free The Airwaves has started with the goal of using the new empty space for Un-Licensed use, like for Wi-Fi.

US markets which have presented unique problems for digital transition include:

• New York City-Newark was one of the early US terrestrial digital television pioneers with state-of-the-art ATSC facilities installed atop the World Trade Center as early as 1998, but those facilities were destroyed in the September 11 attacks, and so New York currently lacks one single point of sufficient height from which to cover the entire region without severe multipath interference issues in downtown Manhattan, New York. The 1776-foot Freedom Tower, proposed to replace the former World Trade Center, will not be completed in time for 2009's DTV transition, requiring the use of multiple booster transmitters to fill gaps in coverage from the Empire State Building. The Metropolitan TV Alliance, a group of eleven rival New York and New Jersey broadcasters, proposes to deploy twenty transmitters across the city to provide adequate quality signal. The market also has caused FCC officials concerns due to large number of viewers who are dependent on over-the-air broadcasts.
• New Orleans, Louisiana and portions of Mississippi were operating some digital transmitters from temporary locations or from towers belonging to other stations due to damage done during Hurricane Katrina and Hurricane Rita in 2005. While stations are now back on-air, the coverage area often does not match that specified on the station licences due to the change in antenna locations.
• Denver, Colorado faces unique multipath interference problems largely due to its mountainous location; its antennas on Lookout Mountain will need to increase in height to overcome obstacles to digital reception, but attempts to get local zoning approval have met with strong opposition.
• Buffalo, New York is one of several markets in which the primary stations are VHF stations that operate on 2, 4, and 7. All three stations were assigned DTV channels in the UHF spectrum, and only channel 7 will be allowed to keep its frequency, and even they will have to reduce power. Because these stations were designed to cover large rural areas south and east of the city of Buffalo, channel 4 was initially grandfathered with a 100,000 watt broadcast power (above the 80,000 watt limit of the VHF low band). All three major stations will lose significant broadcast coverage in the transition, and viewers in the western Twin Tiers region will lose all of their broadcast stations.
• 80 markets were the number of households relying on over the air broadcasts exceeds 100,000 have been identified.

Digital-to-analog converters

After the switch from analog to digital broadcasts is complete, analog TVs will be incapable of receiving over-the-air broadcasts without the addition of a set-top converter box. Consequently, a digital-to-analog converter, an electronic device that connects to an analog television, must be used in order to allow the television to receive digital broadcasts. The box may also be called a "set-top" converter, "digital TV adapter" (DTA), or "digital set-top box" (DSTB).

Coupon program

To assist consumers through the conversion, the U.S. government will take requests from households for up to two $40 coupons for digital-to-analog converter boxes beginning January 1, 2008 via a toll free number or a website. However, these government coupons are limited to an initial sum of $890 million (22,250,000 coupons) with the option to grow to $1.34 billion (33,500,000 coupons) , which is far short of the estimated 112 million households (224 million redeemable coupons) in the United States. Nevertheless, not every household will take advantage of the offer, as reports indicate that 1 in 2 households already has a digital TV.

These coupons may be redeemed toward the purchase of a digital-to-analog converter at brick and mortar, on-line, and telephone retailers that have completed the NTIA certification process. Retail prices for the boxes range from $40 to $70 (plus tax and/or shipping); after applying the coupons, the price to the consumer should be between $5 and $40 per box.

References and notes

External links

• DTVAnswers.com: What you need to know about the February 17, 2009 switch to DTV.
• National Association of Broadcasters
• DTVRedAlert.org
• DTV Transition
• Consumer oriented FCC site
• FCC regulatory information on the DTV transition
• Federal Coupon Program