The new world of TV: crystal clear for (almost) free

Television has quietly been undergoing a digital revolution. This slow moving story of 3 years is not really news, but I'm amazed at how few people seem aware of it. In short:

With a halfway decent antenna, you can get crystal clear broadcast TV. For free.

There are two big breakthroughs. Analog to digital and normal to high resolution. I'll cover those later in the article. But let's just say digital = the sharpest picture ever.

The upside:

1. Assuming you get a semi-decent signal, the picture quality is as good as TV gets. That's the beauty of a digital signal. (I need to verify this, but I believe the over the air signals might be slightly better than cable due to greater bandwidth available). Most stations are 720P, which looks utterly fantastic.
   
2. Once you get the setup working, it is free. This translates to $40-$70 a month saved, which is $500-800 a year.
3. You don't have to give business to a cable company, which many people don't care much for.

The downside:

1. You only get broadcast channels (ABC, CBS, Fox, NBC, PBS stations) and possibly the CW. This will depend on where you live and the nearby broadcast stations.
2. You have to setup the antenna, which can be non-trivial if you need an outdoor mount.
3. You need a digital or HD tuner. The easiest way to do this is either get a recent TV (last 2 years) or get an HD Tivo.

Let's go over the downsides one by one.

1. If you absolutely need premium channels like ESPN, or the Cooking Channel or Sci-Fi, then you have pay. But consider that the cost of these channels is $400-800 / year.
2. Try a cheap indoor antenna if you live in a major city. Namely, get a set of rabbit ears for $12 and see if they work. If not, then you may have to install an antenna on your roof, which will cost $50-80 + $10 for a mounting kit. It will take some physical work.
3. If you have an old TV and can't afford to buy a new one, consider how much you're spending on the cable/dish bill. Or for $250 (or $200 if you find a sale) but an HD Tivo and it will do the decoding and recording (!) for you. You'll also have to pay the $99 annual subscription fee. Or you can buy a low cost converter box and get a coupon to cover some (most (all?) ?) of the cost. There are many articles including this CNET article and the official government web site . Or do a google search on "digital tv converter coupon".

And finally the other big reason why not having a modern TV is no excuse is that in Feb 2009, all old analog broadcasts will stop. So you need to have an upgrade anyways.

Analog versus digital

The old TV from the past two decades was an analog TV signal, which is a lot like listening to someone in a restaurant. You have to work with what you hear even if it does not make sense. The new broadcasts are digital which means they can encode the broadcast to have redundant information, so if some part of the signal is damaged, the receiver can reconstruct the entire signal. If you've seen a weak digital signal break up, it does so disasterously, as none of the picture can be reconstructed. In such a case, the analog signal would look terrible too, but might be watchable.

The digital broadcasts occur on different frequencies, and your TV equipment uses the notation N.1 or N.2 to be channel N broadcast digitally. E.g. Channel 2.1 carries the same info as Channel 2.

Resolution

The other big advance is higher resolution, commonly called HD for High Definition. We measure resolution in the number of lines from the top to the bottom.

• The original resolution is 480.
  
• The mid level resolution is 720. This is considered HD.
• The highest level resolution is 1080. As of 2008, only Blu-ray and HD DVDs are this resolution. This is also considered HD.
  

There's two other aspects of perceived resolution. An interlaced signal draws every other line, each time you fresh the screen. Namely draw horizontal lines 1, 3, 5, ... 359 and the next time draw lines 2, 4, ... 480. This is hold over from the old days when drawing all 480 lines in one pass was not possible. Think of vacuum tubes in the 1960s. An interlaced signal has an "I" appended. The TV standard is 480I. You can also find 720I and 1080I signals. In some ways an interlaced signal only has half the resolution of a full or progressive signal, which draws every line on every refresh. A "P" suffix means progressive. Thus, you will see 480P, 720P and the holy grail of 1080P.

The other change in modern TV is a change in aspect ratio, namely width versus height ratio. Traditionally, TV has had a 4 to 3 ratio, which is almost square. Movies in the theatre had a 16:9 ratio, which is almost twice as wide as it is tall. This is why if you show a wide-screen movie on TV, you get the black bars on top. Modern LCD, LED and plasma TVs have a 16 x 9 aspect ratio because that's the new HD standard.