Ricardo Salaverry and Robert Getsla on the digital TV disaster

Somewhat related to my post yesterday on how big corporations just used digital TV (DTV) as an opportunity to get their patents in, here is a letter I got from my pal Ricardo Salaverry, an engineering manager that has designed ATSC decoder systems.

I liked your article a lot. What I think I mentioned to you is that at the time of selecting the encoding standard the choice was MPEG-2, but at that time there was already a lot of work on MPEG-4 and its variation H.264. The last one is at least twice as more efficient than MPEG-2 that we are using now.

So, we are stuck with a lesser quality encoding system, not to mention the fact that the ATSC "standard" contains 18 standards. To me, a standard is one standard. Eighteen standards is just acknowledging the mess that was created and hide it under the name of "standard".

This mess was created by companies that thought they could profit from the fast implementation of any new thing that would force the consumer and the broadcast industry to buy new TV set, new camcorder and new broadcast equipment.

I do not remember all the companies that were involved on this, but none of them are going to have the profits that they expected at the time. Most of these companies did not have a big presence neither in the consumer nor in the broadcast side of the industry. Dolby was probably the only exception (but I do not remember them all), Zenith ….(is still in business?), Thompson, maybe(?), Compression Labs Inc (the company that invented the video compression) does not exist anymore.

Profits for these companies were going to come from patents. I am guessing that most of these patents were granted before 1998, the year ATSC was adopted. Therefore, at best these companies have at the most another 6 years of profits, since patents expire after 17.5 years.

The swapping of the spectrum is something that I do not understand. I also believe that no matter what is the explanation, I will never understand it. Some say that the TV stations got the spectrum for free…. I came 25 years ago to this country and by the second day I learn that there is nothing free. But, many times people pay for thing that they don’t have the slightest idea that they are paying for. The utility bills are a good example of that.

Now the CEOs of the TV stations are going to buy the spectrum and pay for it from their own pocket….(just joking, everyone else and you and I will pay for it).

I also got a follow-on letter from TV engineer Robert Getsla.

Thank you for hitting the nail on the head. When I first got into television engineering, it was a challenge just to keep all of the television station hardware working long enough to play an hour long video tape without requiring the tweaking of numerous adjustments on the videotape recorder during the tape playback. Eventually we were able to tame most of the worst aspects of NTSC with high speed digital video signal processors, and people became used to watching color pictures that were consistent from program to program and even from channel to channel. And UHF TV signals eventually were almost on an equal footing with VHF TV signals. (Don’t look closely at the operating costs of UHF versus VHF, because there was no contest there. VHF TV is MUCH cheaper to operate than UHF TV.)

I think the real driver behind the impending digital TV train wreck was Congress. Those folks were looking at spectrum auctions as a clever way to balance their budgets back in the 90’s. They had already sold off UHF channels 70 to 83 to become the analog cell phone band and got a lot of money for that chunk of spectrum. There was a group of tech types referred to as the "Grand Alliance" that was pushing for the US to adopt the ATSC system, promising HDTV and better spectrum use, both at once, to Congress. Look again at the companies that were the "Grand Alliance". And yes, you have it right about the patents. COFDM was clearly "not invented here".

I think the reason for packing multiple SDTV streams into one DTV carrier is primarily a multichannel response from the broadcasters to Cable and satellite competition. When Cable offers 100+ SDTV channels, and satellite offers even more SDTV "channels" than cable, why bother fussing with an antenna to get only a small number of local TV "channels" that do not look much better than any of those cable or satellite channels (at least to the casual viewer).

Have you noticed how the Hollywood studios have continued to sit on their 35mm film libraries? HDTV was supposed to be able to reproduce all of the picture detail of a 35 mm film frame. This is why most of the HDTV you see is either live or very recently produced. The huge film libraries of Sony and MGM, etc., are pretty much "off limits" to HDTV broadcasting, and likely to remain so for a while because Hollywood studios are holding back most of their film libraries. They are afraid of what they used to call "the analog hole".

The "analog hole" was the analog interconnection between the DTV tuner and the video display.

If you were wondering why you now need a special cable to connect between your nice new flat screen display and any kind of digital "set top box", the reason is Hollywood’s complaints about "the analog hole". The Hollywood studios insist that the video signal be in a special cable must carry the high definition video serial in digital form running at something like 1.5 gigabits per second. The Hollywood types think that by combining such a high speed digital signal with Digital Rights Management code and with "Broadcast Flag" bits embedded in the data stream, they can prevent most people from recording High Definition movies, by preventing anyone from making "perfect" (digital) copies of them.

On a slightly different matter, the technical problems stemming from packing incompatible signals next to each other have been apparent to some of us for a long time. Consider the story of a UHF TV station assigned to Albuquerque on UHF channel 14 that tried to go on the air in the mid 1980s. The TV transmitters for the Albuquerque area are all located on a small site called Sandia Ridge. Also on Sandia Ridge, close to the UHF and VHF TV transmitters are a number of two way radio repeaters. But there was one particular two-way radio repeater which suffered from a severe interference problem with the UHF TV station on channel 14. Remember, the radio repeater was there first.

The RF input of this narrow band FM repeater was very close to 4.5 MHz below the visual carrier of the TV station. The TV station spent thousands of dollars trying to suppress their "minus side aural" signal enough to allow co-existence with that radio repeater. The UHF station was many dB (40+) below the FCC requirement for spurious emissions from a TV transmitter in their transmission line, but nothing the TV engineers could do short of shutting off their transmitter would satisfy the owner of the two way radio repeater. According to the repeater owner, the TV station was legally required to resolve any and all problems caused by their signal.

There were some relatively simple technical solutions, mostly involving changing the frequency assignments of the repeater, but the repeater owner/operator refused to make ANY changes, insisting that the TV station was causing ALL of the repeater’s problems, so it was up to the television station to make whatever changes were required to resolve the interference problems. This resulted in the TV station eventually going bankrupt and dark.

Later on, it was found that rusty bolts in some of the towers near the two way radio repeater were causing this "minus side aural carrier" to be generated by mixing action between the visual carrier and the aural carrier of the TV station. So, there was no way the TV station could have ever satisfied the demands of the land mobile repeater owner to solve this interference "problem".  

You should have seen the "land mobile" magazines of the time. You would have thought the range wars between the "cattle men" and the "sheep men" had been restarted right there in Albuquerque, but this time, it was the TV folks trying to starve out the land mobile folks. The land mobile folks were downright gleeful when the TV station went bankrupt.

I think most people are just going to have to get used to paying for "free" TV, because I do not see much of an alternative to being able to watch the 3 or 4 DTV channels most people probably will be able to receive over the air. Even if each of those stations running 3 or 4 SDTV streams most of the time, and an HD stream and one SD stream in the evening after dinner, to please Congress. That will be, of course, if they do not experience any jamming from nearby "White space" devices.

It looks like greed and fat brown envelopes under the table have trumped the public interest — again.

Robert also sent along some links on DTV, including Charlie Rhodes on tuner performance. All of Charlie’s TV tech articles are here. Robert is a great source on television issues, it was he who explained to me that a VHF station is much cheaper to operate than a UHF station. I always tend to trust the engineers in the trenches over the politicians and corporate CEOs.

My RF consultant buddy James Long sent a note: “I went by the radio shack store today. They had a chart of the HDTV stations that can be received in Sunnyvale with an indoor antenna. 3 Spanish language and 4 English. All of them independent, specialty stations. No major network stations.” James also noted: “At these frequencies attenuation by trees and buildings is severe. Some years ago I could get ch54 with an indoor antenna and good SNR. As I put up some book cases and they got filled, the signal went down to what looked like 10 dB SNR and I quit watching.”

Both Fox and CBS have run stories on the difficulties with the DTV switch.

Now let’s not get too gloomy about all this. I have also gotten letters from pals that are having good results from DTV. My buddy Alan has reported:

I have a UHF-only antenna with about a 6 foot boom length. Far too directional and too much gain. It’s on a rotator on the mast. I used AntennaWeb to print a listing of all the transmitter directions relative to the homestead. There are a bunch at 306 degrees and another grouping at 356 degrees. I managed to find a midway antenna heading so that I get all the channels without adjusting the indoor rotator box. The key to getting it to operate correctly with the RCA DTV set-top box was to place a 5-dB 75 ohm attenuator pad at the input of the converter to keep the tuner from being overloaded on the front end. Not sure what made me think to try this, but all of the converters were having an issue with picture breakup and since most of these are made for rabbit ears and tiny outdoor antennas, I figured it was worth a try. Success. 26 channels or so including one at 47 degrees and another at 140. Unfortunately many are in languages that I don’t speak. Yesterday I finally turned off the foreign channels and the endless loop weather channels.

The RCA brand converter has a universal remote, unlike the other three brands I purchased. I went out and bought a second RCA converter (Wal-Mart) just so I could have a spare remote. My dad usually picks the channel; I use the second remote to turn down the volume on commercials. The other reason is that at bedtime he was carting his remote off to the bedroom leaving me "remoteless"

Strong wind, rain attenuation and airplane multipath are the only issues that cause reception to break up.

The CRT set I have is a digital ready (DVI Input) Sony that has progressive scan, but plain vanilla NSTC resolution. The picture is phenomenal considering. Life without ghosts and snow is a pleasure. I’ve been enjoying the football games lately. I don’t like football enough to pay for cable or satellite. Don’t like TV or movies enough to invest in an HD display. None of the cheap converters have a DVI output. One of them has an S-Video jack.

There’s an older huge Samsung converter that I purchased a while back that has DVI but the situation on the remote controls was too big a hassle for my dad to use.

The market for higher end converter boxes isn’t that great since most people are tossing CRTs and getting flatscreens with ATSC tuners and don’t need anything external.

Since sending this letter, Alan has removed the attenuator and just shifted the antenna direction in a way that reduces the gain from the strong stations. He is getting dozens of stations. Note that he has a big antenna on the roof. He has also reported that Radio Shack has a Winegard antenna that is optimized for upper VHF and UHF. We may buy one to see how it works. I will let you know. Bob Pease chimed in regarding Alan’s letter: “Alan, if you are correct that the signals are too strong, an attenuator may be a big help. Myself living in SF, with all the crazy hills and a big MISH-MASH of strong and weak signals, I have found that wrapping slabs of tin-foil around my antennas, is often a big help for getting weak signals. I got a friend Ward Glenn who used to live up on Twin Peaks, and from looking out his front steps, he could look up at a 65-degree angle and see that big pickle fork, Sutro Towers. Obviously, those enormous TV signals would over-load every receiver!!”

I guess the whole mess is best summed up by my audio-nut pal Steve Williams, who notes:

Alan, That makes sense to me. In my experience at the dawn of DTV a few years ago as an installer/field service tech, I found that there was a window of tolerance that was a bit more narrow than for normal analog TV as far as signal strength was concerned. The frustrating thing for the non-technical person (here I go on an anti-digital rant) is that the picture is perfect or pixilating and dropping out or gone with no "feedback" as in analog for the person to have any idea as to what is happening. The average person with a set of rabbit ears and an analog TV can twist them around for least multipath and most signal gain without knowing anything except the picture is clearer when I move it here. The average DTV user would not expect that on some channels their signal was too strong and on others too weak, on still others too much multipath and on some just right. All they know is some stations come in perfectly some of the time and the rest don’t. This phenomenon, which can vary literally from house to house, explains why some people love it and have better success than with analog signals, while others can’t get hardly anything when their analog signal was great.

The whole deal with digital TV is that there will be some winners and losers. On balance, lets hope there is a net gain from this whole mess. EDN editor Suzanne Deffree has noted that there are some calls to delay the DTV transition. On this, I would have to say we should stay the course. Another delay just puts off the inevitable pain, although I am sensitive to the claim that we will have cranky old people with osteoporosis up on the roof installing antennas in February. Sorry, we all were warned when the weather was good. Lets just bite the bullet and watch the cable and satellite companies do their damage to the broadcast industry, if only in preparation to what Intel and Google are going to do to them with the whitespaces proposal. And I stand my by call to delay any whitespace deployments until we sort out this DTV fiasco, maybe around September.