April 29th, 2008

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Analog to Digital TV Transition...




And now for something completely different...

      Some people might note that I'm a horse and buggy driving, dirt farming, Winchester wielding throwback and assume that I have something against modern technology. That's not really the case. I've been into computers since the 8k RAM days. Although I think modern technological infrastructure outside the major cities is on borrowed time, I am thoroughly enjoying it while it lasts.

      One bit of technology I've enjoyed far too much over the years is television. And a truly remarkable technology it is. I can't think of anything else that has had so much technological development while maintaining essentially perfect reverse-compatibility for over sixty years. Since commercial broadcast TV was introduced in America, they've added the UHF channels, color video, stereo audio, closed captioning, secondary audio programs, and more... But if you have a 1948 TV in good working condition, you can turn it on and it'll work just fine with the modern TV broadcasts.

      For the rest of this year, anyway. I suppose the TV manufacturers and retailers got jealous of the computer guys, who get to sell people new computers every couple of years as the "old" ones become hopelessly obsolete. People tend to keep TVs until they break down. Noone goes out to buy a new set to get the latest SAP feature. So the electronics industry decided to create a new broadcast standard to force people to buy new sets to replace their old ones, which were being subjected to engineered obsolescence. "We can do far better than the old NTSC standard television!" they cried. "With new, high-definition TV, you'll get picture and sound so much better than NTSC that you'll wonder how you ever watched the old stuff!"

      High-Definition TV was a flop. Truth is, on a normal sized TV screen in typical viewing conditions, the NTSC standard of 525 interlaced scan lines at 60 fields per second is more than good enough. In fact, as the industry was starting to push HDTV, people were just starting to see how good NTSC TVs could really be, as they hooked them up to clear satellite and DVD input.

      So the TV manufacturers went to the Government to FORCE America to accept a new TV standard. Congress found an excuse (vaguely tied to 911, of course) by saying that a switch to the new, digital ATSC standard would free-up radio bandwidth for emergency uses. (Not to mention a bunch of bandwidth the Government can sell to corporations for non-emergency use.) So the Government passed a law that will shut down all those wonderful, reverse-compatible TV broadcasts in February of next year.

      Funny thing is, the Government probably needn't have bothered. Even as the law was being hashed-out, new technologies came along that finally make HDTV worthwhile... The practical limiting factor for TV screen size has always been the cathode ray tube, which had to get deeper as the screen got wider, so that a really big screen TV would take up half your living room. But the development of flat-screen TVs meant that you could have a huge screen that hangs on the wall like a picture frame... And, on a screen that big, you can actually see the 525 scan lines from across the room. So higher definition was actually needed.

      Of course, not everyone has run out to buy big-screen, HDTVs. For those folks who hate to throw away perfectly good NTSC sets, who don't have cable or satellite, and still get their TV through good old rabbit eats or an outdoor antenna, TV goes bye-bye next February...

      But there is a fix... The Government has a program for providing up to two $40 coupons per household to people who need to purchase a converter-box to translate the new ATSC digital signals into something we can watch on our old NTSC analog TV sets. (This actually amounts to giving the electronics companies and Wal-Mart a billion dollars or so in subsidies.)

      A few notes on the conversion to Digital TV broadcasts...

      With either a new TV (with built-in ATSC tuner) or an old TV with a set-top converter box, you will be able to continue watching free TV received through your antenna. You will not have to subscribe to cable, satellite, or anything else. (If you already have cable or satellite, there will be no change in your service for the time being.)

      You will be able to watch HDTV programming with your old TV and a converter box... BUT you will NOT SEE IT IN HIGH DEFINITION. You will see HDTV broadcasts in standard defintion, which is similar in quality to watching a DVD on your old TV set. Your NTSC analog TV is not physically capable of displaying high definition... But, since your old TV doesn't have a huge screen, and you probably won't sit with your face inches from the glass, standard definition should be plenty good enough.

      Digital TV signals are transmitted on the same VHF/UHF frequencies as old analog TV. You do not need a special antenna for digital TV. You may need a better antenna than what you're using now if the signal strength in your area is poor, but that probably means an old-fashioned attic or rooftop antenna. The fancy-shmancy ones advertised as HD or digital generally don't work any better than cheap rabbit ears.

      Digital TV is transmitted in a form similar to computer data... Subject to compression and error correction algorithms. This means there either is enough data for the audio/video to be decoded, or there isn't. In most cases, this should mean that you get DVD quality output, even with a signal that would've been snowy and static-riddled on analog TV. In other cases, it means that you will get no reception whatsoever on channels you would have been able to watch (albeit just barely) on analog.

      The versatility of digital TV will allow each local station to broadcast multiple programs at the same time, effectively increasing the number of channels in your area.

      Using your old VCR to record TV with a converter box will be possible, but a little tricky. Your VCR will "think" it is recording on channel 3 (or 4), and you will have to set the actual channel via the converter box. If you want to watch one program while recording another, the TV and VCR will each need their own converter box.

      Switching channels with digital may be a bit annoying, as there is a delay while the computer "guts" of the system decodes the signal on each new channel. But digital TV does have an on-screen TV guide so you can search for something to watch without actually having to channel-surf.

      A lot of digital programming is broadcast in a wide aspect ratio, rectangular picture, like a movie screen. NTSC analog TVs have a much squarer screen, so the picture doesn't fit. Your converter will allow you to either watch this programming in letterbox mode, with black bands at the top and bottom of the screen so that the whole image fits, or to crop the left and right sides off the wide image to fit it onto your square screen with no black spaces. (Letterboxing is usually preferred, as you lose a good bit of the picture with cropping.)

      People with new-fangled, wide screen TVs have the opposite problem. When they watch programming that was originally framed for square TV screens on their sets, they get black columns to the left and right of the picture. When you watch such a program broadcast on an HD channel with your converter box and NTSC TV, you may get the black columns at the sides, AND the black bands at the top and bottom, essentially giving you a half-sized picture with a black frame all around it. Fortunately, you can use the converter box's zoom/crop function to blow up the picture and get rid of the black frame.

      If you have a really old NTSC TV that has fork and screw antenna attachments rather than the coaxial type, you can get an adapter cheap at Radio Shack or maybe even Wal-Mart. Use the adapter to attach the new socket to the VHF screws, as the converter box will output to your choice of channel 3 or 4.

      Even if you have cable or satellite, it might be a good idea to try a converter box anyway. In some areas you could wind up getting 25-50 DVD quality channels with NO MONTHLY BILL. It might make you wonder why you bother to pay for cable.




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