Why are TV stations going digital?

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PHOENIX -- Analog television goes away on Feb. 17 and digital moves in, but a lot of people are still wondering what that means and why we need to change.

If you really wanted to hear Madonna sing, it would be best to be right there in person. But if you bought a cassette tape, played it a bunch of times and maybe made an extra copy or two, well, Madonna probably wouldn't sound much like Madonna at all.

Compare that to a download on iTunes. That tune sounds just like it did in studio, and on your iPod just like it did on iTunes. Every copy just as clear. That's the beauty of digital. It's stored as computer information. But while music technology moved ahead years ago, TV did not.

"This is a technology that was developed in 1926," said 3TV Chief Engineer Jim Cole. "It became commercially available in the mid-1930s. The last serious change to analog broadcasting was when they added color in 1953."

So while it would best to see Patti Kirkpatrick deliver the news in person, with the old technology called analog news and other progams first of all pass from tape to tape to tape.

"Now in analog, you take that image and that image gets burned to tape and then you take that tape and you have to edit it," Cole said. "So you record to another tape to edit it. Then you record it to master show tape. Then you run it through a switcher. It goes through processing. Each one of those steps there's a degradation. You lose some part of that image."

Then those images are sent out from our transmitter on South Mountain, getting weaker and weaker with every tree or hill and every mile from our site.

That step in the process, you are losing at minimum 25 percent of the picture, probably closer to 40," Cole said.

Which is one of the reasons for the digital switch.

"With a digital system we are able now to deliver a pristine picture right from the front of the camera to the viewers at home," he said.

With an analog signal off antenna, there is snow and some image breakup.. The same show in digital is strong and clean.

And quality isn't the only reason for the switch.

Back in the day, there were just radio and TV stations taking up broadcast space but not anymore.

"The same airwaves we send our signals over are where you get your cellular phones, your Wi-Fi, your Bluetooth," Cole said.

Because digital can put out more information in less space, there's more room for everybody and we can also store more information here as well.

Just like music and videos are stored on your computer hard drive -- all ready to let you enjoy your favorite programs at home, just like you were there.

Now, the government will also be using some of that free air space for emergency services communication. That's another big part of the switch, but for you at home, the real difference will be in picture and sound quality, thanks to the fact information is stored and sent like it would be on a computer, never losing quality no matter how many times it is opened or transmitted.