The United States Senate Commerce Committee is considering a motion to force the US Television industry to completely switch from analog to digital transmissions by April 7, 2009. This means that any legacy televisions that have not been upgraded -- especially handheld and portable units, will no longer receive meaningful transmissions from local stations.
Present day television is transmitted using two methods: digital signals, and the traditional analog signals. The digital signals are produced when the source material is converted to 1's and 0's (just like your computer stuff) and transmitted as such onto the airwaves. Traditional analog signals are created when the source material is modulated along a continous wave onto the airwaves -- no conversion exists.
Video and audio purists may argue that the digital conversions degrade or muddy the final image... that is true, if you examine the codecs involved during the translation. Unless you sample the source (convert) at high rates, you will lose material during the conversion. Of course, the higher rates mean more data (larger files) that have to be moved to the reciepient.
What is pushing this conversion? Two things: technological advancement and money. Yes, digital programming can send along subchannels of data that can be used by the viewer, and that is a neat and useful tool. Some of you may have used this technology when watching a DVD at home, and instead of hearing the full audio track, you selected a different language, or chose to listen to the actors talking about the film during the film.
But the real reason for pushing the conversion is money. The Senate Committee's bill requires the auction of the radio frequencies vacated by the analog TV system to be sold to US Corporations, and raise at least $4.81 billion dollars for the treasury.
Is there a demand for those frequencies? YES! UHF Television consumes 470 MHz through 890 MHz or 6 MHz per UHF channel (remember, 14 - 83). To compare, US FM Radio is 87 - 108 MHz. The US Government is seeing $$ all over the place to sell the frequencies to private industry for a variety of uses -- cell companies for walkie-talkie use, perhaps police and fire stations, perhaps new computer networks or military applications. I doubt we will see a lot of WiFi hotspots in this new area, as the frequencies are not wide enough for fast ethernet-like speeds.
So, what happens to all the traditional analog sets? Well, component digital receivers will be available for purchase to hook into your TV set, performing a translation back to analog that your set understands. If you are on Cable TV, you may have to get a new box. If you are solely interested in watching your purchased DVD's and VCR tapes, those will work just fine -- they are independant of your TV's receiver unit. But all the little handheld TV's and units in the motor home... well... those devices may have to be tossed aside, just like the old rotary-dial telephone.
Who is going to absorb the cost? You are.
While I can see the benefits of having digital transmissions, I hate the idea of having to take a perfectly working TV set and have to invest more money into it. I don't have cable television, nor DirectTV... I watch my Law and Order, CSI, and Star Trek just fine on my 1995 Zenith 19" set.
This article specifically avioded the topic of Digital Rights Management (DRM), as that is another can of worms for another day.