DTV
Ready or Not, DTV is Here!
by Girard Westerberg
Started February, 2002
 


Received here in Lexington on 03/13/02
KTVI-DT (Channel 43), St. Louis, MO - 322 Miles
 

08/18/2008 - I originally wrote this piece several years ago.  As we now move closer to shutting down analog TV broadcasting in the US, and making the transition to digital service, this piece is in need of a major rewrite.  I'll be doing that soon!  In the meantime, much of the information presented here is still relevant and, hopefully, useful.

Overview - Following a long period of technical research and after receiving input from the public and the television industry, the FCC decided that the time had come for U.S. television stations to begin the conversion to a new digital transmission standard, generically known as "DTV."

Each existing television station in the Unites States has been assigned a new TV channel on which to broadcast the new digital format. Currently, U.S. television stations use an analog transmission system known as NTSC.  To help the transition to DTV, television stations will continue to broadcast NTSC on their current analog channels while they bring their digital facilities on line.

According to the FCC, the new digital format offers several advantages over the old analog format that the television industry has used for almost 60 years.  High Definition TV (HDTV) broadcasts over DTV channels will provide the consumer with a much clearer and brilliant picture than currently available on analog broadcasts. Also, the single digital channel provided to each station can be used to broadcast up to five or six standard definition TV channels, with quality similar to that of the analog NTSC signal.  DTV also allows the station to "broadcast" other data services, including various interactive services, internet access, etc.  It is at the broadcasters discretion as to how many program channels or which (if any) additional digital services it broadcasts on it's DTV channel.

Subject to "periodic review," the FCC established what they termed an "aggressive but reasonable" timetable for television stations to complete their transition to DTV.  The transition process is well under way. 

Progress Report - Commercial television stations in the Top 10 markets that are affiliated with the Top 4 commercial networks (ABC, CBS, FOX and NBC) were to have applied for their DTV construction permits as of May 1, 1998. They were to have finished constructing their DTV facilities by May 1, 1999. Several stations did not meet the original deadline for various reasons, including the unavailability of suitable tower space for their antennas.  Toward the end of 2002, however, all of the stations in this category had managed to put DTV facilities on the air.

Commercial television stations affiliated with the Top 4 commercial networks in the 11th though 30th markets were to have applied for their permits by August 1, 1998. They were to have completed construction of their DTV facilities and begun DTV transmission by November 1, 1999. By the end of 2002, 113 of the 119 (95%) stations in this category had managed to put fully licensed DTV facilities on the air.  Eight stations in this category are presently operating under Special Temporary Authority, usually with reduced power, temporary antenna systems, and/or temporary transmitting locations.  Only 6 of the 119 stations in this category have been unable to put a DTV signal on the air. 

All remaining commercial television stations had until May 1, 1999, to apply for their DTV construction permits.  They were to have completed their DTV facilities construction and commenced operating by May 1, 2002.  By the end of November, 2002, only 560 (47%) of the 1,196 stations in the category have DTV facilities on the air.  363 of the 560 (65%)  completed construction of lower power "temporary" facilities under FCC Special Temporary Authority.   This means that as of the end of November, 2002, only 16% of the stations in this category were operating with full power licensed facilities. 

While the FCC seemed open to granting construction deadline extensions during the initial phase of the DTV transition period, especially after the attack on America on September 11th, 2001, that attitude apparently no longer exists.  By the end of 2002, the FCC had made it clear that they would start revoking the construction permits for DTV stations who don't have a genuine, compelling excuse for not being on the air (see a typical "rejection" letter from the FCC at the bottom of this page).  As we approached the end of 2002, a great many of these stations were getting the message, and getting their DTV signals on the air.

In a different category, non-commercial stations have until May 1, 2003 to complete their DTV construction.  As of the end of November, 2002, 81 (22%) of the 373 stations in this category were on the air.  29 of these were operating with reduced facilities under Special Temporary Authority. 

While the FCC's published numbers may indicate that the transition is going reasonably well, I think there are some major problems.

First, many of the stations listed as operating with fully licensed (full power) facilities are, in fact, not doing so!

Generally speaking, all broadcast stations are required to operate pursuant to the terms of their station license.  The station's license specifies technical parameters such as operating frequency, power output, type of antenna, height and location of antenna, and so on.  If a station is unable to maintain the parameters specified in their license for an extended period of time, they must notify the FCC and request Special Temporary Authority to operate at variance from the specified parameters.  For example, if a technical problem prevents a station from operating at licensed power output for an extended period of time, the station must notify the FCC, and give the reasons for the deficiency.  If the deficiency can't be resolved quickly, the FCC will issue Special Temporary Authority to operate at reduced power until repairs can be completed.  This process is designed to cover problems that are beyond the control of the station licensee, such as major component failure, storm damage, temporary operation during construction, and so on.  As a general rule, the FCC will not accept "economic" factors as an excuse for not operating with licensed parameters.  In other words, "my electric bill is too high, so I turned down the transmitter power" is generally not an acceptable excuse for requesting an STA.  Failure to operate with the parameters specified in the station license is one of the more serious of FCC violations -- a "Violation of the Terms of the Station License."

It seems that DTV broadcasters are taking great liberties with the rules these days, and thus far the FCC is letting them get away with it.  I've seen a number of emails from DTV broadcasters stating that they are turning down their power output to reduce the electric bill, typically giving the excuse, "because nobody is watching anyway."  I've got to believe that the FCC is going to do one of their infamous compliance sweeps in the near future, and issue Notices of Violation to the licensed DTV stations that are not operating within the terms of their station license.

This brings us to the next problem -- With regard to the transition to DTV, my opinion is that broadcasters are their own worst enemy. 

I'm a broadcast engineer (radio), and I talk with many other broadcasters, including many in the television industry.  Of the TV people I talk with, the vast majority just don't like DTV.  There seems to be a general resentment stemming from the fact that DTV was "foisted upon them by Congress and the FCC."  To the technical staff, the DTV facilities represent a whole new layer of complex equipment that has to be constructed and maintained, generally without management allocating any additional resources to get the job done.  Station management sees an outlay of capital for construction, and increased ongoing operating expense -- without any meaningful return on investment.  Most people in the TV industry are pretty vocal with their belief that "nobody is watching DTV."  They simply don't see DTV has having any benefit whatsoever.

Here's what I can't understand...  In spite of the TV station's concern that nobody cares about or is watching DTV, many (if not most) of the DTV broadcasters have done nothing to promote DTV!  How will the public ever become aware of DTV or accept it if the stations that are broadcasting it don't even bother to mention it?  A tiny "DT" added to the top of the hour ID is often the only clue a viewer gets that DTV exists in their area.  Of course, most people never see that, or wouldn't know what it meant if they did happen to see it.

It's as if the television industry itself is under the impression that if they ignore DTV it will just go away.  Right or wrong, the United States Congress has a substantial monetary incentive to push the transition to DTV to its ultimate conclusion.   It frees up a lot of spectrum, and Congress wants to auction it off for other communications services.  Since the government expects to make a lot of money from these spectrum auctions, DTV and the eventual abandonment of analog TV will proceed.  The television industry had best realize that resistance is futile, and make the best of the situation.  A well known former CEO of a large broadcast group often said, "either get on the bus, or get run over by it."  The TV industry is standing in the middle of the road, and the bus is rapidly approaching!

The Future - Subject to certain marketplace conditions being met, the transition from analog to digital television is supposed to be complete by the end of 2006.  If everything goes according to plan, all US TV stations are required to abandon their analog broadcasts by December 31, 2006.  Prior to the deadline, stations are to have made the selection as to which of the two TV channels they used during the transition period they will abandon.  Since most stations have a great deal of money invested in logos, graphics, signage, public awareness, etc., for their current analog channel, it's logical to assume that the majority of stations will ultimately choose to abandon the "temporary" digital channel, and shift their digital operations to their old "analog" channel. 

By Congressional mandate, the transition to DTV is to be complete on December 31, 2006. On that date, analog broadcasting is to cease, unless the FCC grants a waiver allowing the continuation of analog broadcasting.  Waivers beyond the deadline will be considered on a market-by-market basis.  The FCC is required to grant a station's request for an extension if one or more of the following circumstances apply: 

(1) One or more stations affiliated with one of the Top-4 networks (ABC, NBC, CBS and FOX) is not yet operating digitally because the FCC granted one or more of those stations an extension of the deadline to complete construction;

(2) Digital-to-analog converters are not generally available to the public in the particular market; or

(3) Fifteen percent or more of the homes in a given market are unable to receive a DTV signal, either over the air or from their cable system, or do not have a television set capable of receiving DTV, or do not have a converter box capable of receiving and converting digital signals to analog for viewing on an analog television set.

Less than 1% of American households are currently equipped to receive local DTV signals in any form, so it seems very unlikely that the December 31, 2006 deadline for total conversion to digital will be met.  In spite of Congressional wishful thinking, it may well be many, many years before the public becomes sufficiently motivated to purchase the equipment necessary to receive DTV.

What is DTV? - DTV is a new "over-the-air" digital television system that will eventually be used by all broadcast television stations in the United States. It's based on technical standards established by the Advanced Television Systems Committee (ATSC), which defines 18 different picture formats that broadcasters can use.  These formats include different levels of picture quality, picture sizes and frame rates.  Perhaps one of the most interesting aspects of DTV is that it allows television stations to broadcast multiple programs simultaneously, each with up to five channels of high-quality sound.

Six of the 18 ATSC DTV formats are defined as High Definition TV (HDTV).  HDTV is defined as any format that provides greater detail than a good quality analog NTSC television picture.  The ATSC standard defines two groups of HDTV formats.  The highest definition (best quality) formats use 1,920 x 1,080 pixel resolution.  The picture can be refreshed 60 times per second at a 2:1 interlace, which yields 30 complete frames per second, or refreshed progressively at either 60, 30 or 24 frames per second.  The other HDTV format group uses 1,280 x 720 pixels refreshed progressively at 60, 30 or 24 frames per second.  All of the HDTV formats are broadcast in a 16:9 "widescreen" aspect ratio.

The remaining 12 formats define Standard Definition Television (SDTV).  These 12 formats are the result of all possible combinations of three picture resolutions with four different frame rates.  The three resolutions are 704 x 480 with pixels compressed slightly to yield a 4:3 aspect ratio, 704 x 480 with pixels expanded slightly to yield a 16:9 "widescreen" aspect ratio, and 640 x 480 with square pixels for a 4:3 aspect ratio.  The later is the closest approximation of  existing analog NTSC video.  Each of these resolutions can be refreshed 60 times per second at a 2:1 interlace, producing 30 complete frames per second, or refreshed progressively at 60, 30 or 24 frames per second.  All of the formats include five discrete channels of audio, plus a low-frequency subwoofer channel. 

Don't worry, your new DTV receiver is supposed to figure out which particular format is being received, and process it correctly for viewing on your TV.  That's the theory, anyway.

The digital TV channel provides the television station with a digital bandwidth of 19.4 Megabits per second.  This is enough bandwidth to transmit a single 1,920 X 1,080 pixel resolution HDTV picture, or a single 1,280 x 720 pixel HDTV picture and a single SDTV picture, or up to four simultaneous SDTV programs. A fifth low-resolution channel (like a weather radar map) can fit along with four SDTV programs. 

The FCC does not require television stations to broadcast HDTV pictures, though Congress has been hinting that they may penalize (through taxes, of course) TV stations that do not meet some to-be-determined minimum HDTV operating schedule.  Congress has also included "interactive or enhanced " television services in their DTV wish list. They haven't exactly defined what they mean by "interactive or enhanced," or what the penalties might be for not doing it, whatever "it" turns out to be..

DTV video makes maximum use of the available bandwidth by using a digital compression method established by the Motion Picture Experts Group (MPEG).  DTV uses the MPEG-2 compression standard.  The MPEG-2 standard uses various data compression techniques including Discrete Cosine Transformation (DCT), motion estimation, and predicted frames.  Likewise, the audio portion of the program is compressed using the Dolby Digital AC-3 compression standard.

Again, don't worry.  Your new DTV receiver will automatically know how to "uncompress" and process the audio and video.

Some History - In 1998 the Federal Communications Commission promised that "...the arrival of over-the-air digital television will be one of the most significant developments in television technology since the advent of color television in the 1950's."  That promise remains virtually unfulfilled even though the television industry's transition to DTV has now been under way for several years.

Will DTV eventually live up to the FCC's promise?  I suppose it depends on how you choose to define what the FCC meant by "significant development."  I'm sure the television broadcast industry views DTV as a significant development since they are the ones footing the bill for the initial transition.  However, with the majority of Americans seemingly unaware that DTV even exists, it surely can't be claimed that the American public assigns any particular significance to DTV or the technology on which it is based.  From the perspective of the American public, DTV may never live up to the FCC's promise.

I also believe the FCC erred in comparing the arrival of DTV to the advent of color television back in the 1950's.   There are several key differences between the introduction of DTV and the arrival of color TV.

(1) The introduction of color television was widely publicized and promoted.  DTV has not been given much publicity or promotion by manufacturing groups or the television industry itself.  The public remains mostly unaware that DTV is being broadcast or even exists. Perhaps the television industry hasn't yet figured out a way to convince the public that DTV is "better."

(2)  Color television was a technical advancement that even the most casual TV viewer could see and appreciate.  DTV absolutely does provide the viewer with better pictures and sound, but will the average viewer be able to tell the difference?  Will the average viewer care?

(3)  Television broadcasting in the '50's had only the movie industry as a competing visual medium.  The movie industry helped television's transition to color by having introduced color to the public several years earlier.  Today's over-the-air broadcaster has stiff competition from cable, direct broadcast satellite services, video discs, etc.  The public does not have to embrace over-the-air DTV broadcasts to get its entertainment fix.

(4)  Most importantly, color television was backwards compatible with existing black and white television.  Television shows broadcast in color could still be viewed on existing black and white televisions.  Conversely, DTV can not be received on existing analog television sets.  Reception of over-the-air DTV signals will require the purchase of new equipment.

Yet, with everything it had going for it, color television did not become the overnight success that Congress and the FCC seem to be think DTV will be. 

The FCC authorized the first color broadcasts to begin on December 23, 1953.  It was just a few days later when the first coast-to-coast network color broadcast took place -- The  Rose Parade from Pasadena, California, aired on January 1, 1954.   At the time, there were only 200 color television sets in circulation, all 12 inch models custom built by RCA.  Far more people saw the parade in person than on color TV.  

In March, 1954, RCA introduced the first mass produced color television sets to the American public.  Built around RCA's patented CT-100 chassis design, the set sold for around $1,000.  That was a BIG chunk of change when you consider that you could buy a brand new, full-sized Ford automobile for around $1,600!   Even with the high price tag, RCA managed to sell somewhere around 5,000 color TVs during 1954.  However, color programming was scarce.  NBC aired only 68 hours of color programming during all of 1954.  It wasn't until five years later, in 1959, that NBC added "Bonanza" to its lineup as the first regularly scheduled program to be broadcast in color.  Then, in the fall of 1961, broadcast of "Walt Disney's Wonderful World of Color" began.  The popularity of Disney's show contributed further to the public's acceptance of color broadcasting.  Even so, it wasn't until 1966, 12 full years after color TV was introduced, that NBC became the first network to broadcast all of its programming in color.

From the public's perspective, there was nothing complicated about the switch from black and white to color television.  As a consumer, if you wanted color TV, and you could afford it, you simply went out and bought a color TV set.  Your local TV channels didn't move, and your old black & white TV still worked.  Yet, it still took over 10 years for color television to evolve from an expensive curiosity to a viable, full-time television broadcast medium.

The transition to DTV will not be as simple and straightforward as the transition to color was.  Unlike color television, the digital television service is not backwards compatible with the existing analog television service we've been using for almost six decades.  Because standard, non-digital ready television sets can not receive, process and display DTV signals, consumers will eventually have to purchase new equipment if they wish to watch the over-the-air DTV signals of their local TV stations.  Set-top receivers and converter boxes are available that will allow you to watch DTV material on a standard television.  However, because most existing television sets are not designed to display the higher resolution pictures and different screen sizes available with DTV, set-top receivers and converter boxes are not the perfect solution to the problem of DTV's inherent incompatibility with the many millions of analog television sets that are in use today.  And, let's face it, it's not realistic to expect consumers to spend several hundred dollars on a set-top converter to make an $89 portable analog television set receive DTV! 

DTV and Cable -  The majority (better than 70%) of American households receive their local television stations through their local cable system rather than over the air.  Under current FCC’s rules, cable operators are required to carry a certain number of local TV stations based on the cable system’s capacity.  The introduction of DTV raises some very serious issues relating to the "must carry" rules.

As it stands now, cable systems do not have to carry a local television station's DTV signal until the station abandons its analog broadcasts.  However, even though a DTV station may be utilizing DTV's ability to broadcast multiple programs, cable systems will be required to carry only a single program, the one that the TV station designates as being its "primary" service. 

The FCC rules also dictate that, "to the extent technically feasible, the quality of signal processing and carriage provided by a cable system for the carriage of local commercial TV stations will be no less than that provided by a system for carriage of any other type of signal."
In the context of DTV, the FCC determined that a cable operator may not provide a digital broadcast signal in a lesser format or lower resolution than that afforded to any other digital programmer carried on the cable system — broadcast or non-broadcast.  The FCC goes on to say, "[cable] operators retain the discretion to transmit signals in 720p in lieu of 1080i."

In other words, you are not likely to see any change in the way your cable system does business.  Nor are you likely to see any improvement in the quality of the local TV stations you receive through your cable system.  It can be argued that the cable operator's only incentive in all of this is to maintain the status quo.  Indeed, cable systems will probably sell more subscriptions when over-the-air analog broadcasts cease.  Most Americans will probably conclude that a cable subscription is cheaper and more convenient that going out and buying new DTV equipment and putting up an antenna to receive local TV stations.  Others will probably conclude that going to any trouble or expense to continue receiving their local TV stations just isn't worth it.  When local TV broadcasters are forced to abandon their analog channels, many consumers will abandon local TV.

The transition from analog to digital over the air broadcasting is clearly in trouble. Already several yeas into the transition, consumer awareness of and demand for DTV is virtually non-existent.  One television industry observer recently said, "It’s more likely that we’ll see the Dow Jones at 20,000, than we will see DTV transition in 2006." 

 

TV DXing and DTV


KDKA-DT (Ch 25), Pittsburgh, PA - 294 Miles
As seen here in Lexington, KY on 05/05/02

The transition to DTV is already presenting DXers with some interesting opportunities and challenges.  As the transition to digital television progresses, new DTV signals are popping up in ever increasing numbers.  A TV DXer equipped to receive DTV has an interesting assortment of new DX targets to go after these days.  At the same time, new local and semi-local DTV operations are effectively blocking the reception of any distant co- and adjacent- channel analog signals.  More about that later...

During the DTV transition period, there will eventually be as many as twice the number of television signals on the air as there were before the transition began.  These signals will be packed into fewer channels because TV channels 52 through 69 are being reassigned to non-television users, causing further congestion of the "core" television channels (channels 2 through 51).  While the FCC has made every effort to reduce interference issues, a number of observers have already reported the mysterious weakening or total loss of semi-local analog signals.  This is undoubtedly the result of new DTV operations powering up on the same channel. 

One interesting aspect of DTV is that you can not really "see" it on an analog television receiver.  If you tune your analog TV to a channel occupied by a strong, local DTV station, you'll see what looks like "big" analog snow.  Most people won't even be able to tell that there is a signal on the channel.  However, any analog signal that was viewable on the channel prior to the local DTV station coming on the air will be obliterated. 

Kentucky Educational Television's (KET) extensive array of both analog and digital channels scattered around Kentucky gives us the opportunity to do a little experimenting. 

For this particular experiment, I used KET's analog WKPC (channel 15), Louisville, KY from a distance of 79 miles, and co-channel digital WKMR-DT (also channel 15), Morehead, KY from a distance of 59 miles.  From my receiving location the antenna azimuth for WKPC is 290°, and WKMR-DT is 77°.  In other words, with the antenna aimed at WKPC, digital WKMR-DT is almost in the exact opposite direction, off the "back" of the antenna.


Analog WKPC (ch 15), Louisville, KY - 79 Miles
Picture taken before WKMR-DT signed on.
02/16/02 @ 7:56:00 AM EST


Analog WKPC (ch 15), Louisville, KY - 79 Miles
Picture taken after WKMR-DT signed on.
02/16/02 @ 7:56:30 AM EST

These pictures were taken approximately thirty seconds apart.  The antenna was peaked on WKPC, and was not moved between taking the two pictures.  As you can see, WKPC's analog signal went from very viewable to almost gone! 

What about WKMR-DT's digital signal during this experiment?


Digital WKMR-DT (ch 15), Moorhead, KY - 59 miles
02/16/02 @ 7:57:00 AM EST

As you can see, when we swung the antenna around toward WKMR-DT, WKPC's analog "interference" off the back of the antenna did NOT prevent us from getting a perfect digital picture.

DTV receivers are currently designed to work with a certain amount of interference, which comes in two basic forms:  multipath and noise.

Multipath occurs when the received signal arrives from two or more different paths.  That is, when the transmitted signal is reflected off of a building or some other reflective surface, and combines with the "direct" signal at the receiver.  The reflected signal travels a greater distance to get to the receiving antenna than does the direct signal.  Because the reflected and direct signal path lengths are not equal, each signal shows up at the receiver slightly out of phase with the other.  In the analog world, the result is ghosting or multiple images.  Ghosting of an analog picture is annoying, but it doesn't destroy the picture.  However, left uncorrected, multipath would destroy the integrity of the DTV digital bit stream, rendering the digital signal unusable. 

Fortunately, DTV receivers contain an adaptive equalizer that suppresses the weaker of the two signals so that it can successfully process the remaining, stronger digital bit stream.  The DTV's adaptive equalizer is typically capable of correcting multipath conditions even when there is only a slight level difference between the direct and reflected signal.

It appears to me that the current crop of DTV receivers handle multipath very well!  By rotating my antennas around, it doesn't take much movement to induce ugly ghosting in the pictures of my local analogs.  At the same time, it's very difficult for me to induce any disruption or digital breakup in the associated DTVs, which are operating from the same towers.  People often blame digital breakup on multipath.  I suspect that in most cases they are actually having problems with noise and co-channel analog interference.

A DTV receiver sees everything other than correctable multipath as noise.  This includes power line noise, ignition noise, and other forms of electrical interference.  The DTV noise interference category also includes both co-channel analog and digital broadcast signals.

The Trellis Coded 8-level Vestigial Side Band (or just 8-VSB) digital modulation scheme used by American DTV requires a theoretical carrier-to-noise ratio of just under 16 db for successful demodulation.  In other words, for the receiver to display a clean picture, the digital carrier must be almost 16 db stronger than any noise source that may be present on the channel.  With digital TV, getting a picture is pretty much an all or nothing proposition.  If the signal to noise ratio is sufficient, we get perfect, interference-free pictures. If the DTV signal to noise ratio is insufficient, we get nothing. 

In contrast, an interfering signal at less than 50 db below the level of an analog TV signal can be seen.  However, the analog signal will tolerate a fairly large amount of interference before it is totally destroyed.

This is probably a good time to point out that our DTV receiver is supposed to include a means to fight off interference from co-channel analog TV signals.  A "comb-filter" is included to notch out the analog television signal's video, audio and color burst carriers, resulting in a further improvement in the DTV receiver's ability to perform successfully in the presence of analog interference.  Unfortunately, my own observations and the observations of many others have shown that it takes very little co-channel analog interference to destroy DTV reception.  Newer generations of DTV receiver chip sets are supposed to improve the receiver's ability to cope with all forms of interference.

Because DTV doesn't need as large a carrier-to-noise ratio as analog to produce perfect pictures, a DTV station will need less transmitted power than its analog counterpart to service the same coverage area on the same channel.  The FCC determined that a power reduction of approximately 12 db will be appropriate for DTV to maintain a given coverage area.  However, the FCC is pretty much allowing DTV stations to operate at whatever power is necessary to replicate their existing analog grade B service area as long as they don't cause interference to another station.  Does this mean that all TV stations will reduce their effective radiated power output?  No!  Some stations will reduce power, and others will actually increase their power.

It takes more power at UHF frequencies to cover a given geographical area than it does at VHF frequencies.  That's why analog UHF TV stations run as much as 5 million watts, while stations operating on channel 2 run a maximum of only 100 kilowatts.  In theory, the 5 million watts on UHF gives about the same coverage area as the 100 kilowatts on channel 2 does. 

At least during the DTV transition period, many VHF analog stations will be operating their DTV facilities on a UHF channel, thus requiring more power to theoretically cover the same area as their VHF analog counterpart.  Take WLS-TV in Chicago, for example.  Their analog facilities on channel 7 operates with 81.3 kilowatts.  WLS-DT has been assigned channel 52 during the transition period with a radiated power output of 153.6 kilowatts.  KWGN-TV in Denver provides an even more extreme example.  KWGN-TV operates on channel 2 with 100 kilowatts.  They hold a construction permit for DTV operation on channel 34 with 1 million watts of radiated power.

There are a few cases where analog UHF stations have been given DTV assignments in the VHF television band.  These stations will typically operate their DTV facilities with much less power.  Our own local WDKY is one such station.  They presently operate analog facilities on channel 56 with 3.39 million watts (and are asking for 5 million watts).  The FCC has assigned them VHF channel 4 for their DTV operations, with only 36.4 kilowatts.  {WDKY apparently doesn't want to stay on channel 4... They have applied for reassignment of their DTV facility to channel 22.) 

The FCC's goal in assigning DTV power levels is to replicate as closely as possible the station's existing analog grade B coverage contour.  When the transition from analog to digital is complete, each station's coverage area should end up being very close to what it was with the old analog channel. 

During the transition period the FCC is allowing DTV facilities to operate at reduced power, and many (if not most) are doing just that.  This is presumably to make it easier for stations to get their DTV channel on the air.  Again, our own WDKY provides an example of the extremes some stations will go to to avoid spending money and putting up real DTV facilities. This station is operating under an STA with a maximum effective radiated power of 7.5 kilowatts.  They apparently didn't want to invest in a real transmitter, so to squeeze out this amount of power they are using a very low power transmitter into highly directional, high-gain antenna.  That antenna is pointed away from Lexington, presumably toward their city of license, Danville, Kentucky .  Granted, Lexington is not WDKY's city of license, but they very much act like a Lexington station and they are our only FOX outlet.  I live on the south side of Lexington, and WDKY is squirting an incredible 12.6 watts toward me!  From 18 miles away, it isn't enough.  I guess I won't be able to watch NASCAR on DTV next year! 

Many of the DTV stations we target for DX will be operating at reduced power and limited coverage areas, and will often be operating with limited broadcast schedules.  Low power DTV signals and the co-channel analog interference that will be with us until analog TV broadcasting is ultimately abandoned certainly presents us with some reception challenges. However, based on the results myself and others have achieved already in the early transition period to DTV, it seems apparent that DXing DTV is possible in spite of these obstacles. 


02/09/02 - KSDK-DT (channel 35), Saint Louis, MO
320 miles


02/09/02 - WLS-DT (channel 52), Chicago, IL
317 miles

In one way, DXing DTV is easier than DXing analog TV.  The American DTV system incorporates a collection of data tables describing virtual channel attributes, events and other information.  This system is known as the Program and System Information Protocol or PSIP.  Without going into all the details (I don't understand them, and apparently neither do many TV stations!), the PSIP is data that is transmitted along with a station's broadcast signal that tells DTV receivers important information about the station and what is being broadcast. The most important function of PSIP is to provide a method for DTV receivers to identify a DTV station and to tell the DTV receiver how to properly tune it.  The DXer can use the PSIP data (if present) to easily ID the station, like this...
 

In addition to identifying the channel, PSIP tells the receiver whether multiple program channels are being broadcast and, if so, how to find them. It also identifies whether the programs are closed captioned, conveys V-chip information, or if data is associated with the program, and much more.  My DX receptions of both KSDK-DT and WLS-DT were identified via their PSIP data. 

According to the National Association of Broadcasters (NAB), "...if broadcasters do not include properly encoded PSIP data in their DTV signals, receivers may not correctly identify and tune to the station. Therefore, it is vital that all broadcasters understand PSIP and include the data in their DTV stations signals. PSIP is a mandatory component of the Advanced Television Systems Committee (ATSC) Standard."  Unfortunately, the NAB reports that as many as 70% of the DTV stations that are on the air haven't yet figured out how to properly implement their PSIP, but sooner or later they will have to get it right.

Since DTV is so new, nobody has had the opportunity yet to capture digital TV DX via sporadic E, meteor scatter or the other very long-distance propagation modes.  It's only a matter of time before a DTV DXer makes history by reaching this exciting milestone.  I tend to think we'll reach this milestone sooner than later. 

UPDATE:  At 8:22 AM on Friday, May 30, 2003 a TV DX milestone was finally attained.  I was able to successfully decode the PSIP ID for KOTA-DT (channel 2), Rapid City, ND from a distance of 1,062 miles. 

The reception came during a fairly intense and long-lasting sporadic E opening.  This is the first known reception of a DTV station via sporadic E.  It is the longest reception of a DTV station on record.

Jeff Kadet of Macomb, IL blazed the trail by doing the early DTV DX work.  Then, Jeff Kruszka of Baton Rouge, LA set a new distance record for a DTV reception when he received WNCN-DT (ch 55), Goldsboro, NC from 835 miles on May 11, 2003.  Jeff's reception was via some excellent tropospheric conditions, and remains the longest UHF DTV reception..

The most important aspect of these receptions is that all the speculation about whether or not you can DX DTV is over.  DXing DTV not only can be done, but has been done.  I have no doubt that our distance records will fall.  Many more sporadic E and long-haul tropo receptions of DTV stations will surely occur, probably sooner than later. 

In summary, I hear a lot of TV DXers whining about how DTV is "ruining" the hobby by taking away their DX channels.  Yes, we've all lost "open" channels to DTV, but we've also gained many new DX targets.  In my opinion, TV DXers are missing out if they do not have DTV capability.  There are already many DTV stations on the air, and more hitting the airwaves every day.  Not having DTV is like like having a TV that tunes only half of the available channels!  Like it or not, DTV is here, and it presents a wonderful new environment for television DXing!  Get on the bus, or get run over by it!

 

DXing With the Hauppauge WinTV-D Computer Card
Updated 06/07/03

WinTV-D is a computer card that allows you to watch Digital TV on your PC screen. It includes a Dolby Digital audio decoder (AC3) for 5 speaker surround sound, analog and digital video outputs, remote control and can also receive conventional over-the-air analog or cable television broadcast signals.  For the TV DXer the WinTV-D provides a very convenient means to produce high quality JPEG screen captures of either analog or digital television receptions.


The "Basic" On-Screen WinTV-D User Interface
WKSO-DT (Ch 14), Somerset, KY

I use the WinTV-D computer card for all my DTV receptions.  Almost all of the screen captures you see here on this web site, both analog and digital, were produced using the WinTV-D. 

Perhaps the best thing about the WinTV-D card for the DTV DXer is that it's fairly basic.  In other words, it doesn't try to do your thinking for you like many of the DTV set-top boxes. 

Some consumer DTV receivers (like the Hughes HIRD-E86) want to give you a selection of available channels based on your Zip Code.  This is obviously a ridiculous and useless "feature" for the DTV DXer (and everyone else I would think).  Some don't allow manual channel selection, but give you a selection of "available" channels based on an automatic channel scan. Again, not good for DX. Others insist on remapping to DTV "virtual" channels so that the channel being displayed is not the true RF channel.  Some won't even detect a DTV signal if the PSIP data is invalid, and there are a great many DTV stations that are broadcasting with invalid PSIP data.  In other words, most (if not all) set-top boxes being produced so far are so "user friendly" (read: for stupid users) that they are not at all well suited for DTV DXing. 

Perhaps the most useful "feature" for the TV DXer is WinTV-D's diagnostics screen.  When I'm surfing for DTV signals I always have this screen up. This screen gives you a variety of technical details, including Signal to Noise Ratio (SNR), data error rate, and a variety of technical details about the material being transmitted.  The AGC voltage reading enables precise antenna aiming.  But, perhaps the most important reading is the Carrier Offset indication.  If you know how to read it, it provides a positive indication of even the weakest DTV signal.


The WinTV-D "Diagnostics" Screen

Here are some specific tips I can offer for DXing with the Hauppauge WinTV-D card.  First, pay attention to the "Carrier Offset" reading on the diagnostic screen.  This is the best way to detect that a DTV signal is present on the channel.  A low, reasonably stable number indicates the presence of a DTV signal.  Conversely, a wildly fluctuating high number indicates that any DTV signal that may be on the channel is too weak to detect.  Here are a few examples of Carrier Offset readings, and what they mean.

 
Three examples of carrier offset readings when a DTV signal is present.
 
 
Typical carrier offset reading with a strong analog signal
 
Typical carrier offset reading with no analog or digital signal

The carrier offset reading an extremely sensitive tool for detecting DTV signals.  You may detect a DTV signal, but that doesn't always mean you'll be able to lock on a signal and decode a picture or PSIP.  For that to happen the "Sync Lock" and "EQ Lock" indicators have to turn green, and the "Errors/1 sec" reading has to be somewhere below 300.  Here are some basic examples...


A DTV signal is present, but far too weak to decode a Picture or PSIP.
Close, but not quite!

 


A weak DTV signal.  It's just at the threshold to decode a Picture or PSIP.
Usually close enough for DX work!


A strong DTV signal.  This will decode a perfect picture and PSIP.
Easy Reception!

 

With a very marginal DTV signal, you may only get a full signal lock for a very brief moment as the signal fades up and down.  With the WinTV-D card you can easily detect the presence of a digital signal, peak the signal up using the AGC reading, then wait for the signal to fade up enough to get a lock and display a frame.

To illustrate this technique, here's a frame captured from my DX reception of WPXI-DT, Pittsburgh.  The signal was so marginal I received only ONE frame of recognizable video.  Even that frame was riddled with errors, but there was enough to clearly identify the station. This reception would have probably been impossible on any of the "smarter" receivers.


A Single Frame Captured From
WPXI-DT (Ch 48), Pittsburgh, PA
294 Miles

It should be noted that the WinTV-D card will continue displaying the last decoded frame it got until a new one comes along.  In other words, if the DTV signal fades out on you, the WinTV-D card will continue displaying the last frame it got before the station faded.  It will not revert to the dreaded "blue" or blank screen when the signal goes away.  This "feature" enabled me to capture the single frame I got from WPXI-DT.

Moving along, the WinTV-D provides several useful utility screens.  This one is what I call the basic operations menu.  This allows you to select operating resolution, program service, channel suite selection, as well as the basic file and program operations and preferences.


The WinTV-D Program Service and Operations Menu

I've been told that the Win-TV-D card isn't the most sensitive or selective television receiver around.  That may be true, but it's analog performance seems to be equal to or better than every other television receiver I have.  I really don't have any way to judge it's overall  sensitivity and selectivity for receiving DTV signals with respect to other receivers.  I can only say that I've gotten decent results, and I haven't seen or heard of a better receiver for DXing DTV yet.

One last thing... The Win-TV-D card does NOT display true HD.  It is a DTV receiver, not an HDTV receiver.  Hauppauge makes the Win-TV-HD receiver card, which does true HD.  However, unlike the Win-TV-D, the HD version does NOT have a composite video output.  Most DXers consider that an unacceptable loss, as it prevents one from recording video on a VCR, for example.  I often use the Win-TV-D's video output to feed DTV into this web site's Live TV DX Web Cam, and I would not want to give up that feature.  All in all, the Win-TV-D card is more than enough to explore the future of DTV DXing. 

Does DTV work?  Take a close look.  You be the judge...


Analog
WKRC (ch 12), Cincinnati, OH
78 Miles
 

Digital
WKRC-DT (ch 31), Cincinnati, OH
78 Miles

I will update this section as developments dictate!  Stay tuned....


DTV Tuner Shootout - During December 2003 I had the pleasure of hosting a small gathering of DTV DX enthusiasts from the region.  From Lexington, Glen Hale, Tom McSorley and myself were present.  Steve Rich and Greg Baker were kind enough to come down from Indiana.  Glen, Steve and Greg brought their DTV receivers, and I included my WinTV-D in the tests.

I've always wondered how my Hauppauge WinTV-D tuner would stack up against other set-top boxes.  This shootout gave us the opportunity to test various tuners against each other in our never-ending quest to find the "best" unit for DX purposes. 

The following receivers were tested:  The Zenith HDSAT520, Samsung SIR-T151, RCA-ATSC1, and the Hauppauge WinTV-D (DTV tuner on a computer card).  During the tests two equal RF outputs from my VHF and UHF antenna system were used.  The WinTV-D card was connected to one port, while the various tuners under test were connected to the other.  Each tuner was tested to see how fast it detected and locked to a DTV signal, how long it would hold the lock, and how it handled various PSIP defects.

General Observations - Glen's Zenith HDSAT520 was the overall winner.  It was probably the most sensitive of all the tuners tested.  It's NTSC tuner was also very sensitive, making it a good overall DX TV tuner.

Greg's RCA-ATSC1 also performed quite well.  It's RF sensitivity seemed to be as good as the Zenith, but the Zenith is a little more "DX friendly" in terms of operation.  Nevertheless, the RCA proved to be a good tuner, and Greg gets some fantastic results with his.

Steve's Samsung SIR-T151 was the worst of the tuners we tested.  It would not even detect the presence of a DTV signals when all the other tuners were able to decode a perfect picture.  I had tried out another SIR-T151 here during October, and found it to be very insensitive compared to the WinTV-D card.  During our most recent tests, the performance of Steve's SIR-T151 was exactly as poor as the unit I had tested earlier.  I believe we have confirmed that the Samsung SIR-T151 DTV tuner is NOT the one to buy if you are looking for good overall tuner performance. 

My WinTV-D card actually did much better than I thought it would.  It's DTV sensitivity was, for all practical purposes, equal to to the Zenith and RCA tuners.  In every case, it locked to and decoded a DTV signal at the same signal levels as the Zenith and RCA tuners.  However, it would not maintain a lock under more severe signal conditions when the others would.  The Zenith and RCA tuners apparently use a newer generation of decoding chips than those used in the WinTV-D card.  As a result, the WinTV-D card is not quite as good at decoding and holding a DTV signal in the presence of analog interference, or through signal fades.  On the other hand, the WinTV-D card is, by far, the most "DX friendly" of any of the DTV tuners we tested. 

It was interesting to see how the different receivers handle defective PSIP data.  Unfortunately, many DTV stations transmit defective or incompatible PSIP information, and there doesn't seem to be any one tuner that handles all of these defects perfectly. 

One station transmitting defective PSIP data in our region is WLJC-DT (ch 7), out of Beattyville, KY.  Neither the Samsung or the WinTV-D card would decode them during the tests, in spite of a very strong signal.  On the other hand, the Zenith and the RCA had no problems decoding WLJC-DT.  I should note that WLJC-DT is not always "broken".  Apparently, somebody re-boots their encoder every now and then, and I can decode their signal perfectly.  Lately, however, they seem to be "broken" more often than not.

Just before our testing, WUPX-DT (ch 21), Morehead, KY added several program channels to their stream.  They apparently badly botched the PSIP programming when they added the new channels.  Strangely, the WinTV-D card was the only tuner that could decode WUPX-DT during the tests, and managed to display the non-standard screen formats they have programmed into their PSIP.  The other tuners simply ignored the WUPX-DT signal as if it weren't there at all -- not good if you expect anybody to watch your station over the air.

The Local Kentucky Educational Television (KET) stations transmit two identical audio channel choices for each of their program channels.  I can not say that this is a defect in their PSIP programming, but it does cause a problem with the WinTV-D card.  While the WinTV-D card will decode the audio and video on KET's program channels, it will not switch from one program channel to another.  If you attempt to switch program channels, you simply get a frozen picture.  The program channel you get when you change to one of KET's RF channels is random.  To change program channels you have change RF channels, then return to the KET channel and hope the program channel you want comes up.  I've encountered this situation with a couple of other DTV stations, so KET are not the only ones with this particular PSIP "strangeness"   And, it's interesting to note that the WinTV-D card is the only tuner that we tested that can't handle this particular situation.  The Zenith, RCA and Samsung all handle KET's PSIP data perfectly, and have no difficulty switching between program channels.  Is this a defect in the WinTV-D card decoding scheme?  When I find out, I'll let you know.


The following is typical of the "rejection" letters the FCC has been sending out to stations requesting further DTV construction extensions.  As you can tell by the tone of the letter, the FCC is being less than friendly about this... 

 

           Federal Communications Commission
                    Washington, D.C. 20554

June 14, 2002

WEYS Television Corporation
c/o Robert Goldstein
P.O. Box 1471
Evergreen Colorado 80437

                                                                                                          Re: Request for Extension of Time to Construct
                                                                                                                 Digital Facilities
                                                                                                                 WEYS-DT, Key West, Florida
                                                                                                                 File No. BEPCDT-20020228ACS
                                                                                                                 Facility ID No. 72053

Dear Permittee:

This letter concerns the application on FCC Form 337 filed on behalf of WEYS Television Corp. ("WEYS") for an extension of time to construct the digital facilities of WEYSDT.

As originally filed, WEYS asserted that it was unable to construct facilities by the applicable deadline due to technical and legal reasons. Specifically, WEYS asserted that, following the filing of the application for WEYS-DT, the tower owner discovered that the tower would not be able to support the additional antenna required for digital broadcasting. WEYS further stated that it was in the process of preparing to petition the Commission for rulemaking to change WEYS-DT’s channel in order to avoid man-made noise and long distance signal skip.

By letter dated March 29, 2002 the Chief, Video Division, Media Bureau, sought additional information concerning your application. The letter explained that in the Fifth Report and Order in its DTV proceeding, the Commission announced its willingness to grant, on a case-by-case basis, an extension of the applicable DTV construction deadline where a broadcaster has been unable to complete construction due to circumstances that are either unforeseeable or beyond the permittee’s control, provided the broadcaster has taken all reasonable steps to resolve the problem expeditiously.1 In addition, FCC Form 337 requires that an applicant seeking an extension of time must provide specific reasons in support of an extension, as well as the specific steps it has taken to mitigate any problems.

As initially filed, WEYS’s application was incomplete with respect to these matters, and you were specifically asked in the March 29th letter to provide updated information regarding the status of your proposed petition for a channel change and whether alternative sites were considered. We also sought information regarding: (1) a specific plan outlining how WEYS will use the extension time to further the construction of WEYS-DT; and (2) the date upon which it anticipates that construction will be complete.

------------------------------------------------

1 Advanced Television Systems and Their Impact upon the Existing Television Broadcast Service, Fifth Report and Order, 12 FCC Rcd 12809 (1997).

-1-

In response to our request, you submitted an amendment stating that you could not complete construction of WEYS-DT because of the necessity of changing WEYS-DT from channel 3 to a channel in the UHF spectrum. You indicated that this change of channel was required primarily for two reasons. First, you stated that there is increasing concern among engineering professionals as to the viability of low band VHF TV channels for digital television signal transmission due to man-made noise and "skip" interference. Further, you stated that since the allotted effective radiated power ("ERP") of WEYS-DT is only 1 kW, the noise and interference factors weigh especially heavily in having an effective DTV station in the Key West, Florida market. You explained that substituting a UHF television channel reduces the possibility of interference with the DTV signal reception, since man-made noise is greatly diminished in the UHF spectrum and "skip" interference is not probable.

Second, you asserted that after the application for a construction permit on channel 3 was filed, the third party tower owner determined that the existing tower could not safely accommodate another antenna. You stated that the tower owner has obtained a permit to construct a stronger tower, but has not established a time schedule for replacing the existing tower. With the proposed change in WEYS-DT’s channel to one in the UHF spectrum, you asserted that the WEYS digital and analog signals (proposed digital channel 20 & existing analog channel 22) could be multiplexed into the same antenna, thus solving the existing tower space problem regardless of when the new, stronger tower is built. Further, you indicated that appropriate, alternative tower sites for WEYS-DT were not practical or in the public interest.  You asserted that in order to put a signal over the area of license, potential locations were severely limited and Monroe County issued a moratorium on the building of new towers. You further stated that the tower housing the WEYS analog antenna is in downtown Key West and provides a superior location. You asserted that it would be in the public interest to keep the WEYS-DT antenna at this location, if at all possible.

In addition, you stated that WEYS has engaged a consulting engineer, Byron St. Clair, to prepare the engineering studies required to petition for a rule making to move WEYS-DT to a more suitable channel in the UHF band. Since the filing of the FCC Form 337, you stated that Mr. St. Clair has identified channel 20 as an appropriate and available alternative to channel 3, and has completed all of the required engineering materials. Further, you stated that you were preparing the Petition for Rule Making to Amend the Table of Allotments as well as the accompanying FCC Form 301, and would file these documents as expeditiously as possible. You anticipated that these filings would be completed no later than April 30, 2002.

Moreover, you asserted that you would use the extension time to complete the regulatory work required to change WEYS-DT’s channel from 3 to 20, order the appropriate digital equipment and build the station. You stated that because WEYS’ ability to build WEYS-DT on channel 20 was dependent on action by the Commission, it was impossible to anticipate when construction would be completed. However, you asserted that, provided the change to channel 20 was approved, you anticipated that you would be able to expeditiously complete construction of WEYS-DT following regulatory approval. Finally, you stated that you have had discussions

-2-

with equipment suppliers, but cannot finalize purchase decisions until the rule making is resolved and the FCC Form 301 is acted upon.

Based on the information before us, you have failed to sufficiently explain your previous efforts to meet the May 1, 2002 DTV construction deadline. In this regard, we fail to see why no feasible tower site or antenna system could be completed before the May 1st deadline, particularly since you received the construction permit for WEYS-DT over two years ago.Although you indicate that your ability to build WEYS-DT on channel 20 is dependent on action  by the Commission, we find it unreasonable that you did not file the petition for rulemaking to move WEYS-DT to the UHF band during this entire two-year period.3 Consequently, you cannot give a projected date as to when the station’s transmitter and antenna will be ordered.  Therefore, your showing contains no reasonable plan or projected date by which any DTV facility might be constructed and placed into operation.

For these reasons, we conclude that an extension of the construction permit in this case is not justified and must be denied, with the permittee admonished for its failure to comply with its DTV construction obligations. We believe, however, that WEYS should be afforded until December 1, 2002, to come into compliance with the DTV construction rule. In this regard, WEYS will be required to submit a report within thirty (30) days of this letter outlining the steps it intends to take to complete construction and the approximate date that it expects to reach each of these construction milestones. Absent extraordinary and compelling circumstances, the construction completion date should be no later than December 1, 2002. Sixty (60) days after submitting its initial report, the station will be required to submit a report detailing its progress on meeting its proposed construction milestones and justifying any delays it has encountered. If at any time during this period, the station fails to demonstrate that it is taking all reasonable steps to complete construction or fails to justify the further delays it has encountered, or we otherwise find that the permittee has acted in bad faith, the permittee will be subject to the imposition of additional sanctions. Failure to complete construction of its DTV facilities by December 1, 2002, will result in a monetary forfeiture against WEYS, and the initiation of a six-month process, at the end of which, if the DTV facilities still have not been constructed, absent good cause shown, the subject DTV construction permit will be rescinded.

------------------------------------------------

2 The construction permit for WEYS-DT was issued on March 3, 2000.

3 While you asserted in the amendment that you anticipated filing this petition no later than April 30, 2002, to date, it has still not been filed.

-3-

In light of the above discussion, IT IS ORDERED That WEYS Television Corp. IS HEREBY ADMONISHED for its failure to comply with its DTV construction obligations. Moreover, IT IS FURTHER ORDERED That WEYS Television Corp.’s request to extend the construction permit for WEYS-DT IS DENIED, and the applicant is afforded until December 1, 2002 in which to come into compliance with the DTV construction rules as set forth herein.

Sincerely,

W. Kenneth Ferree
Chief, Media Bureau

cc: WEYS Television Corp.
2539 North Highway 67
Sedalia, Colorado 80135

 

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Many such highly entertaining letters can be found at:

http://www.fcc.gov/mb/video/files/dendtvextreq.pdf

Additional FCC letters and statistics relating to DTV can be found at:

http://www.fcc.gov/mb/video/dtvstatus.html