Digital TV encoding allows stations to offer higher definition video and better sound quality than analog, as well as allowing the option of programming multiple
digital subchannels (multicasting). However, it provides these advantages at the cost of a severe limitation of broadcast range. Digital signals do not have "grade B" signal areas, and are either "in perfectly" or "not in at all". Further, since most stations have preferred to use UHF rather than older VHF channel allocations, their actual broadcast range is far less than it was previously. Viewers in major metropolitan areas will likely not notice problems; however, rural TV users have generally had most or all of the stations they previously received with acceptable but not "perfect" signals fall over the
digital cliff (where analog signals slowly degrade over long distances rather than digital suddenly cutting off when out of range). Lastly, many low-power broadcasters have been temporarily permitted to transmit in analog for several years.
Consumer awareness Although the
United Kingdom spent the equivalent of more than a billion dollars educating about 60 million people, the
National Telecommunications and Information Administration had received $5 million a year before the original transition date of February 17, 2009, and the FCC had received $2.5 million and was scheduled to receive $20 million more later in the year, for 300 million people, requiring voluntary education campaigns. It was also noted that
low-income,
elderly,
disabled,
inner city, immigrants, and rural Americans were targeted the most, because these groups mainly watched analog antenna TV more than any other groups. While broadcasters were forced by
Federal Communications Commission regulations to devote the equivalent of more than a billion dollars' worth of airtime to
public service announcements regarding the digital transition, the amount of information conveyed in these short advertisements was by necessity limited. Both the on-air announcements and government-funded telephone hotlines receiving viewer inquiries directed consumers to Internet sites to seek information, at a time when most affected were not familiar with the Internet.
Obsolete equipment After the switch, consumers' old analog televisions, VCRs, DVRs, and other devices which lacked a digital tuner no longer received over-the-air television. Though previously recorded content can still be replayed, new content cannot be accessed. Another solution was the use of a cable TV or satellite TV service, as these providers handled the necessary conversion within their respective systems and could provide the analog signal these older analog devices required. Users of analog VCRs, DVRs, or other recording devices which lacked a digital tuner had the unique problem of no longer being able to record programs across multiple channels. In order to record multiple DTV channels, the viewer had to use an external tuner box and set the device to record the output from that box, typically L-1 for the line input. Some manufacturers sold external converter boxes or tuners that automatically changed channels at preset times. The analog VCR or DVR may record at preset times, but will continue recording the L-1 line input, which would be the same channel unless the channel is manually changed. Alternatively, the user may purchase a new TV, DVR, or DVD recorder with a built-in digital tuner. However, these newer technologies have their own drawbacks, such as being limited to only 1–2 hours with high-quality XP mode (DVD-R).
Loss of service A major concern is that the broadcast technology used for ATSC signals called
8VSB has problems receiving signals inside buildings and in urban areas, largely due to
multipath reception issues which cause
ghosting and
fading on analog images, but can also 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, and the image on the screen freezes, or blinks back and forth to and from a completely black image. The maximum power for
DTV broadcast classes is also substantially lower; one-fifth of the legal limits for the former full-power analog services. This is because there are only eight different states in which an 8VSB signal can be in at any one moment; thus, like all digital transmissions, very little signal is required at the receiver in order to decode it. Nonetheless, this limit is often too low for many stations to reach many rural areas, which was an alleged benefit in the FCC's choice of ATSC and 8VSB over worldwide-standard
DVB-T and its
COFDM modulation. Additionally, without the
hierarchical modulation of DVB, signal loss is complete, and there is no switch to a lower resolution before this occurs. A hundred-kW analog station on
TV channels
2 to 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 frequency which it occupied since the 1950s in order to transmit more power (up to 1000 kW) on the less-crowded
UHF TV band. Such stations can keep the same channel number, however, because of ATSC
virtual channels. The higher frequencies are challenged in areas where signals must travel great distances or encounter significant terrestrial obstacles. Most stations in the low-VHF (channels 2–6) did not return to these frequencies after the transition. About 40 stations remained in the low-VHF after the transition, with the majority in smaller markets (with a few notable exceptions). The FCC has long discouraged the digital allocation on low-VHF channels for several reasons: higher ambient noise, interference with
FM radio (channel 6 borders FM at 88 MHz), and larger antenna size required for these channels. After the transition, many viewers using "high-definition" antennas have reported problems receiving stations that broadcast on VHF channels. This is because some of the new antennas marketed as "HDTV antennas" from manufacturers such as
Channel Master were only designed for channels 7–51 and are more compact than their channel 2–69 counterparts. These manufacturers did not anticipate widespread continued use of the relatively longer
wavelength low-VHF channels. Stations broadcasting on channel 6, using the original analog standard, had an additional benefit of having their audio broadcast on 87.7 MHz FM, which is at the very low end of the
FM radio dial. As such, many stations on channel 6 took advantage of this, and promoted this feature, especially during
drive time newscasts, and as a critical source of information in markets where severe weather (such as
hurricanes) allowed a station to broadcast their audio via FM radio without having to contract with another FM operation to do so.
WDSU in New Orleans, Miami's
WTVJ and
WECT in
Wilmington, North Carolina were among the most well-known Channel 6 broadcasters which used this approach to provide emergency information during hurricanes. Digital television, however, does not have this feature, and after a transition to the ATSC 1.0 digital standard, this additional method of reception is no longer available.
WRGB, channel 6 in
Albany, New York, employing a variation of the ATSC 1.0 digital TV standard, used a separate transmitter on 87.7 that transmitted a vertically
polarized analog audio signal, which would theoretically avoid interference with the horizontally polarized digital TV signal. This would allow the station to keep its audio on 87.7 FM after the transition to digital. WRGB ran this transmitter for approximately 6 weeks on an experimental basis, only to find that the vertically polarized 87.7 MHz signal interfered with the digital video, while broadcast of analog signals on 87.9 MHz was met with FCC objections.
WITI in
Milwaukee took a more direct, though still experimental, approach to restore their TV audio, having it restored in August 2009 to an
HD Radio subchannel of
WMIL-FM via a content agreement with WMIL owner
Clear Channel Communications. A purchase of HD Radio equipment or having a car stereo equipped with an HD Radio receiver is required to listen to this broadcast. A variation of the ATSC 3.0 standard, developed for Low Power TV (LPTV) stations, includes an analog FM signal on 87.7, in addition to the digital video. The FCC refers to these stations as
"FM6" operations. Planning for DTV reception assumed "a properly oriented, high-gain antenna mounted 30 feet in the air outside." The
Consumer Electronics Association set up a website called AntennaWeb to identify the means needed to provide the correct signal reception to over-the-air viewers. Another website, TVFool 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 estimated that marginally more stations would be gained than lost by viewers, this varied widely with viewers of low-VHF analog signals in distant-fringe areas among the most adversely affected. An estimated 1.8 million people were expected to lose the ability to access over-the-air TV entirely as a result of the digital transition. Viewers in rural and mountainous regions were particularly prone to lose all reception after digital transition.
Problems U.S. markets which have presented unique problems for digital transition include: • New York City-
Newark was one of the early U.S. 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 for a number of years, New York lacked one single point of sufficient height from which to cover the entire region without severe
multipath interference issues in downtown
Manhattan. The 1776-foot
1 World Trade Center, proposed to replace the former World Trade Center, would not be completed for some time, so several scenarios were considered to enhance service. One such system, called
distributed transmission, was being funded by a $30 million federal
grant to assure that no viewers are left without service. The DTS would have used low power transmitters to fill gaps in coverage from the
Empire State Building. The
Metropolitan Television Alliance, a group of eleven New York and New Jersey broadcasters organized soon after the destruction of the facilities at the World Trade Center, has been leading the development of the DTS system. In 2004, a partial solution was implemented: the top of the
Condé Nast Building at 4
Times Square was reinforced and installed with a massive
multiplexed UHF antenna. This relieves overcrowding at Empire State by using the site of a local
Clear Channel radio facility to replace master antenna installations destroyed at WTC. • New Orleans 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 licenses due to the change in antenna locations. •
Denver 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 been met with strong
opposition. Federal legislation was ultimately used to require that Denver stations be allowed to construct their post-transition digital facilities but sharp nulls and gaps in coverage remain. • Sparsely populated mountainous regions such as
Montana and
Utah currently rely heavily on
broadcast translators to rebroadcast network stations into underserved communities; while these low-power retransmitters are not themselves required to broadcast digitally, many will need costly upgrades to receive a digital signal from the originating station—if the signal can be received at all. 23% of the 4000 licensed translators have received a federal subsidy to make the conversion, but many others will simply go
dark. In sparsely populated markets such as
Glendive, Montana, translators are needed to reach a widely scattered audience but the readiness of many small municipally owned translators remains largely unknown. • Many other stations in the
Rocky Mountains had chosen to end analog broadcasts early because of poor winter conditions at transmission sites in February; stations needed to be sure they can make the on-site adjustments. For these broadcasters, the
DTV Delay Act and its extended deadline of June 12, 2009, came too late to be of use, as the digital transition had already been completed. •
Vermont, a market in which all major stations are, as of February 2009, digital-only, is problematic as it is both a rural state and a mountainous region.
WCAX CBS 3 in
Burlington, and
WPTZ NBC 5 in
Plattsburgh, New York are now both UHF broadcasts from
Mount Mansfield, causing many viewers to lose access to the stations. Previously as analog VHF stations, WCAX transmitted from Mount Mansfield, while WPTZ was broadcast from Terry Mountain in
Peru, New York, on the opposite shore of
Lake Champlain. •
Buffalo, New York, a city whose stations mostly broadcast from among the
Boston Hills and cover a fairly rugged terrain along the
Appalachian Plateau, is one of several markets in which the primary stations are VHF stations that operate on channels 2, 4, and 7. All three stations were assigned DTV channels in the UHF spectrum; all had lost significant broadcast coverage in the transition, and viewers in the western
Twin Tiers region lost all of their broadcast stations. In May 2009, both WIVB (channel 4) and WGRZ (channel 2) warned its viewers that were not in Erie or Niagara Counties that they would likely lose the broadcast signal, reducing the station's coverage area from approximately 12 counties to just two, along with several parts of
southern Ontario, a critical viewing audience for all Buffalo stations. •
Syracuse, New York had since 1948 employed
low-VHF channels to feed networks to adjacent markets (notably
CBS to the northern two-thirds of the
Utica market and
NBC to the southern half of the
Watertown market). These markets are 60 to 75 miles (100 to 125 km) away. Utica lost CBS service because its affiliate, based in Syracuse, broadcasts on
channel 5 analog (with a signal strong enough to reach Utica), but its channel 47 digital signal does not reach anywhere near Utica. Channel 5 had historically refused to cede its Utica territory to another potential affiliate, but in October 2015, CBS signed an affiliation deal with NBC affiliate
WKTV, which restored CBS service to the Utica market via its second digital subchannel (prior to this,
Binghamton affiliate
WBNG-TV (channel 12) had served the southern third of the Utica market, which corresponds to
the Cooperstown area). Similarly,
Watertown, New York and
Kingston, Ontario lost Syracuse NBC affiliate
WSTM-TV once the DTV transition rendered Syracuse a
UHF island; WSTM-TV continues to be shown on local cable systems. Like CBS in Utica, NBC eventually restored service to the Watertown market, signing an affiliation deal with new sign-on
WVNC-LD in November 2016. • On January 15, 2009,
Hawaii became the first state in the United States to have its television stations switch from analog to digital early. Existing analog facilities at
Mount Haleakala on
Maui are to be removed due to ongoing
radio interference with
astronomy equipment operated under the watchful eye of the
United States Department of Defense and the
University of Hawaii. The digital stations are being deployed using new facilities at Ulupalakua and the old towers will be removed before bird
nesting season begins in March. By making the switch early, the broadcast towers atop Haleakala near the birds' nesting grounds can be dismantled without interfering with the
Hawaiian petrels' nesting season. • Between June 12, 2009, and July 1, 2009, programs on the Fox network were unavailable to viewers throughout the state of
Montana (except viewers in the
Billings area) who did not have cable or satellite service. The stations in
Butte,
Great Falls and
Missoula were among many full-powered stations owned by
Equity Broadcasting. Equity filed for
Chapter 11 bankruptcy in 2008, and the stations went
silent on June 12, 2009, due to the inability to fund construction of digital facilities. Unlike most established broadcasters, Equity had expanded rapidly using outlying UHF stations as satellite-fed repeaters. Many but not all were low-power TV stations, typically carrying
Univisión or smaller networks such as
UPN (later
The CW) and
The WB (later
MyNetworkTV). The majority of Equity's full-power operations came to the air after 1997, by which time the digital transition was already in progress. The stations were therefore not allocated a second, digital companion channel and were not required to simulcast digitally until their required
flash-cut to digital signals at the end of transition. Although Equity conducted a successful auction for the stations in April 2009, the required federal government approval came too late for the new owner,
Max Media, to do the flash cuts. Eventually, Max Media chose to move the affiliation to digital subchannels of their respective new sister stations, all ABC affiliates. Other stations formerly owned by Equity, such as
KUOK in
Oklahoma City, were able to make flash-cuts under new ownership and are still on the air. Many stations were sold at auction to
Daystar Television Network, which will construct the digital facilities and air religious programming on the acquired stations; in some cases, these went silent, returning to operation after slightly less than a year off-air in order to avoid losing the full-service licenses. At least one affected station,
WNGS Buffalo (now WBBZ-TV), had been subsequently resold while silent. (In all, the FCC signed on 136 full-power stations after the original allocation of digital signals.) Except for the full-service Equity stations, almost all were able to flash-cut by the deadline. Notable exceptions were
Pappas-owned KCWK (which went silent several months before digital transition was originally to be completed and never returned; KCWK's license was cancelled by the FCC on June 2, 2009) and
WWAZ-TV (which returned in August 2012 to the air). There are 80
media markets in which more than 100,000 households receive television signals by over-the-air broadcasts. There are no channels set aside for analog broadcasts of the
Emergency Alert System, rendering most portable emergency
TV sets useless. While a small number of portable ATSC sets have started to appear, these are costly. A portable converter box (such as Winegard's RCDT09A) would require a bulky external battery, and
mobile ATSC is not yet available. Another option would be getting a
USB-based
TV tuner card for their
laptop computer, which in addition to its low costs became a popular option after
Microsoft released
Windows 7 four months after the DTV transition ended. A
Google-sponsored program called
Free the Airwaves sought to use the "empty"
white space within the remaining TV for unlicensed use, like for
Wi-Fi. In March 2008, the FCC requested public comment on turning the bandwidth currently occupied by analog television channels 5 and 6 (76–88 MHz) over to extending the FM broadcast band when the digital television transition was to be completed in February 2009 (ultimately delayed to June 2009). This proposed allocation would effectively assign frequencies corresponding to the existing Japanese FM radio service (which begins at 76 MHz) for use as an extension to the existing North American FM broadcast band. On August 22, 2011, the
United States'
Federal Communications Commission announced a freeze on all future applications for broadcast stations requesting to use channel 51, to prevent
adjacent-channel interference (ACI) to the A-Block of the 700MHz band. Later that year (on December 16, 2011),
Industry Canada and the
CRTC followed suit in placing a moratorium on future television stations using
Channel 51 for broadcast use, to prevent ACI to the A-Block of the 700MHz band. ==Digital-to-analog converters==