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Digital broadcast TV explained

Good-bye analog, hello digital: People who watch TV using an antenna to receive signals from broadcast towers such as this one were affected by the government's mandate that full-power analog TV broadcasts be ended no later than June 12, 2009. Full-power TV stations in the U.S. now broadcast only digital signals. An ATSC tuner is needed to receive these signals. (photo by Chris Lee)

People will need TVs or other devices with ATSC tuners, rather than the old NTSC tuners, to receive [digital] signals.

Digital broadcast TV explained
(especially for people living in the Green Bay or Madison television markets)

	Disclaimer:
	The content on this Web page is provided as a public service. Every effort is made to provide accurate information. However, as with any human endeavor, mistakes are possible. Please e-mail any suggested corrections to info@leemark.com. Copyright © 2007-2012 Leemark Communications.

By Chris Lee
Owner, Leemark Communications

First published online: May 16, 2007
Last updated: February 7, 2012

This article is geared toward people who
don't have cable television or satellite dish
service and receive their TV signals off air.
In other words: with an antenna. In other words: free TV.

The change to digital television broadcasting requires some changes, but also provides some potential benefits, for people who receive their television off air with an antenna.

	Definitions:
	ATSC tuner -- a TV tuner that will receive digital broadcasts. Depending on the type of device or display, an ATSC tuner may not always be capable of displaying a certain program in its original (native) resolution. ATSC stands for Advanced Television Systems Committee. analog broadcasting -- type of TV broadcasting in use since the early days of TV in the United States; uses an NTSC tuner to tune in channels. digital broadcasting -- new type of TV broadcasting that uses a signal composed of ones and zeros. An ATSC tuner is used to receive these signals. Programs can be transmitted in various resolutions and digital TVs may be capable of displaying SDTV, EDTV, HDTV or all three types. interlaced scan -- type of TV broadcasting which transmits all of the even numbered lines in a television picture frame (2, 4, 6, etc.), then all of the odd numbered lines (1, 3, 5, etc.), to make up one frame, and then repeats for the next frame. NTSC broadcasting uses the interlaced method. NTSC tuner -- type of TV tuner around since the early days of TV in the United States; it receives analog broadcasts. A TV purchased before 2005, or a VCR or DVD recorder purchased before mid-2007, most likely has only an NTSC tuner in it, not ATSC. NTSC stands for National Television System Committee. progressive scan -- type of TV broadcasting which displays all of the lines in a television picture frame sequentially, in the method: line 1, line 2, line 3, line 4, etc. without skipping lines as in the interlaced method. Three types of digital television: SDTV (standard definition) -- displays the digital signal but at the standard aspect ratio (4/3) and with 480 interlaced horizontal lines of resolution. It is similar to NTSC analog TV in terms of resolution but is transmitted digitally. EDTV (enhanced definition) -- displays the digital signal at the wide-screen aspect ratio (16/9) and with 480 progressive horizontal lines of resolution, which gives a better picture than using 480 interlaced lines. EDTV televisions are also capable of displaying signals with 480 interlaced lines of resolution. HDTV (high definition) -- displays the digital signal at the wide-screen aspect ratio (16/9) and with either 720 progressive horizontal lines, 1080 interlaced horizontal lines or 1080 progressive horizontal lines of resolution. HDTV televisions are also capable of displaying signals with 480 interlaced or 480 progressive lines of resolution.

The end of analog broadcasting for full-power TV stations

June 12, 2009 was the last day for analog broadcasting by full-power television stations in the U.S. Those stations now broadcast only in digital. According to the federal government Web site dtv.gov, this "will free up parts of the broadcast spectrum for public safety as well as other valuable uses."

Exception:
Low-power (LPTV), Class A, and translator TV stations did not have to meet the June 12, 2009 deadline. (Many religious broadcasters run low-power TV stations, for example.) The Federal Communications Commission says these stations will eventually have to convert to digital broadcasting, but as of June 2008, "there is currently no deadline for them to turn off their analog signals." Source: www.fcc.gov/cgb/consumerfacts/ DTVandLPTV.html

If you receive your TV signals off the air, your old TVs with NTSC tuners won't receive any full-power stations in the U.S. anymore, unless you take certain steps. The same is true for old VCRs and even DVD recorders (with NTSC tuners). You will either need to get a new TV that has an ATSC (digital) tuner, a DTV converter box, or a VCR or DVD recorder with an ATSC tuner in it, in order to receive full-power TV stations off the air.

Any device with an ATSC tuner in it should be able to show all of the various kinds of digital broadcast television being used in the United States. However, a certain device might not be able to show a program at its "native," higher resolution, but instead may drop it down to a resolution it is capable of displaying.

The mandate for ATSC tuners

As of March 1, 2007, the FCC required every new VCR, DVD recorder, and TV manufactured for sale in the U.S., if it had any tuner at all in it, to have the capability to receive digital broadcast television signals. This means having an ATSC tuner and associated circuitry.

However, some manufacturers get around this mandate by having no tuner in the DVD recorder. Be careful when buying to look for "ATSC tuner," if you get your TV off-air. If the product has an "SDTV," "EDTV" or "HDTV" logo on it, or a "DTV" logo, that should mean it has an ATSC tuner in it.

If you buy a DVD recorder with an ATSC tuner in it, you can use that as your tuner for getting digital television on your old TV. Of course, you might not be able to watch one TV show and record another under this setup, unless you have a TV that also has an ATSC tuner in it.

For people who didn't want to spend the money on a new TV or DVD recorder, the government ran a coupon program that provided $40 off the price of a DTV converter box. A converter box contains an ATSC tuner to let you watch digital TV on an old analog TV set.

The Good News

While it angers some people that they had to get a new device in order to continue receiving TV off air, there is some good news in all of this. Digital broadcasting has allowed many people who receive only off-the-air (free) TV to get more stations than before. This is because with digital, stations can compress the video and fit multiple "channels" of programming on their single digital channel assignment.

For example, in Madison, Wisconsin, using our mid-1990s TV with an NTSC tuner, we were able to receive six network affiliate stations off the air, not counting low-power religious stations. But with a digital (ATSC) tuner, we are able to watch 14 channels as of early November 2010, all for free.

Digital TV for Madison market station call letters network affiliate displayed channel actual channel WISC-DT CBS 3.1 50 WISC-DT2  (TVW) MyNetworkTV 3.2 50 WMTV-DT NBC 15.1 19 WMTV-WX (TrueView 24/7 weather) AccuWeather 15.2 19 WHA-DT (Wisconsin Public TV) PBS 21.1 20 WHA-DT2 (The Wisconsin Channel) PBS 21.2 20 WHA-DT3 (WPT Create) PBS 21.3 20 WKOW-DT ABC 27.1 26 WKOW-DT2 Me-TV 27.2 26 WKOW-DT3 This TV 27.3 26 WMSN-DT FOX 47.1 49 WMSN-DT2 theCoolTV (music videos) 47.2 49 WMSN-DT3 TCN (The Country Network) 47.3 49 WBUW-DT The CW 57.1 32

Even better is the fact that all 14 channels we receive come in very good, with no ghosting, graininess or fuzz. The digital TV signal is composed of ones and zeros, so if your ATSC tuner can receive the signal well enough to determine the ones and zeros, the picture quality will be good.

In the Green Bay market, meanwhile, depending on one's location and antenna, old NTSC tuners could potentially receive up to seven network affiliate stations off the air, not counting low-power religious stations. By using a device with a digital (ATSC) tuner, viewers can receive 12 channels as of December 2010, all for free.

Digital TV for Green Bay market station call letters network affiliate displayed channel actual channel WBAY-DT ABC 2.1 23 WBAY-WX (Stormcenter 2 24/7) -- 2.2 23 WBAY-DT3 Live Well Network 2.3 23 WFRV-DT CBS 5.1 39 WLUK-DT FOX 11.1 11 WCWF-DT The CW 14.1 21 WGBA-DT NBC 26.1 41 WGBA-DT2 Me-TV 26.2 41 WACY-DT MyNetworkTV 32.1 27 WPNE-DT (Wisconsin Public TV) PBS 38.1 42 WPNE-DT2 (The Wisconsin Channel) PBS 38.2 42 WPNE-DT3 (WPT Create) PBS 38.3 42

For example, WBAY-TV in Green Bay and WMTV-TV in Madison both put their regular programming on one part of their digital space and a 24-hour weather channel on a second "channel" (Stormcenter 2 24/7 and TrueView 24/7, respectively).

See the charts at right for a complete list of channels. Other stations may add additional programming on their digital channels in the future.

It is important to note that although these channels are digital, not all of the content is high definition.

Choosing an antenna

In a given TV market, the channels used for digital broadcasting may be in the UHF band, the VHF band, or both.

Back to the antenna: TV antennas don't always have the traditional roof-top design, or even "rabbit-ears" design for indoor antennas. This photo shows a Philips MANT950 amplified TV antenna mounted on the side of a house, under the eave of the roof. (The inset photo shows a wider view, including copper wire that grounds the antenna in case of a lightning strike.) The MANT950 is a VHF/UHF antenna for indoor or outdoor use and can be mounted on a wall, in an attic, to a railing, or on a mast with a rotor. This antenna works great for receiving digital television signals at our house, but we are on a hill and only about 10-12 miles from the TV towers in Madison. We could also use an amplified indoor table-top antenna. If either of these solutions do not work well enough in your case, a traditional roof-top antenna may be needed. (photo by Chris Lee)

Any VHF/UHF antenna should work with an ATSC tuner -- the antenna does not have to say "HDTV compatible" on it. In fact, if all of the digital TV stations in your market are on the UHF band, you would only need a UHF antenna to receive them.

While any VHF/UHF antenna may work in theory for receiving digital TV signals, in practice, getting a usable signal depends on the quality of the antenna and its placement, as well as your particular location in relation to the TV broadcast towers.

A simple non-amplified indoor antenna (sometimes called "rabbit ears") may work fine if you are relatively close to the TV broadcast towers. Of course, an outdoor antenna mounted on a rooftop will usually give you more consistent reception, and often bring in more stations, especially if you are farther away from the TV towers (such as in a different city) or if there are obstacles in between you and the towers or other reception problems. In between these two choices are an amplified indoor antenna and an amplified outdoor-type antenna placed in an attic.

As of June 12, 2009, all the full-power digital TV stations in the Green Bay market were in the UHF band except WLUK-DT (FOX 11), which had its digital signal on channel 11 (VHF).

In the Madison market, as of November 5, 2010, all the full-power digital TV stations were in the UHF band.

More information on choosing an antenna can be found at the Consumer Electronics Association's antennaweb.org Web site.

A new era in television

In summary, the transition to digital TV broadcasting in the United States has greatly affected people who receive their television off the air. Since June 12, 2009, full-power local TV stations are able to broadcast only digital signals. This means that people need devices with ATSC tuners in order to view the TV channels via antenna. While this change may be inconvenient and require some expense, it also brings with it some positives, such as better picture and potentially more channels.

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