IP-005 What is the “Digital Cliff”?
Reader Patricia wrote me to toss an Internet Pumpkin asking if I can explain the digital cliff she’s been hearing about, and exactly what causes it, and for that matter, what can be done to avoid it.
I’m no Graphic Artist, but I play one on TV, so maybe a picture will help visualize what happens. The graph on the right plots picture quality versus signal strength in an analog world. As the signal strength goes down, the picture quality goes down and you see noise or ghosting in the video. The weaker the signal gets, the worse the picture gets, until you loose audio and video totally. Up until the last gasp of signal, you may be able to make out what’s on the screen or what show is on, and it wouldn’t be easy to watch, but you actually might be able to bear it long enough to follow the program.
With DTV, the picture quality does not change at all as the strength gets lower, until it hits the “cliff”. As the signal strength decreases below the level your receiver needs, the picture quality suffers very quickly. At the mid-point of the slope, where you might still be able to tolerate a weak analog signal, the DTV signal would be breaking up so badly, you’d turn the TV off or change the channel. Digital break-up is extremely annoying while trying to watch a show.
How annoying depends on your receiver. Some will mute the audio and some will allow an ear piercing pop, garbled digital noise, and repeated blips of dialog for several seconds. As you know, I am not afraid of heights, but I really want to stay away from the digital cliff at all costs and avoid the slippery slide down into the abyss of aggravation.
The only way to avoid the cliff is a good antenna. If you’ve read my blog for awhile, you know I recommend an outdoor antenna wherever possible. The attic will work to hide it, and lastly a good quality directional indoor antenna. Again, don’t be duped by the “Super Deluxe 50-60 dB gain amplified HDTV bunny ears on steroids with a spare tire looking center cap all in one snake oil powered set top antennas”. Look around the house and see what you have first. Try it, you might like it. Remember Kyle’s antenna? How about building one for yourself for a few bucks?
Then go shopping for an advanced antenna and grill the store salesperson about how many returns a certain antenna generates. I’ve found BB and CC to be very honest and open about this, at least with me, so talk to them and see what is working for most of their customers. The brand new Best Buy in Knightdale has the most impressive display of indoor antennas I’ve seen during my shopping sprees, and I’m sure most stores have what you need in stock.
While a CECB or even an HDTV is a purchase a “man shopper” can handle just fine, I urge you to talk to the sales people in the stores about the antenna options. If you don’t get the answers you’re looking for, move on to the next store and so on until you have enough information to make the right choice. Even then, ask what their return policy is if it does not work for you.
Do I have to type in all caps to drive home the fact that the antenna is the most important part of your new DTV home theatre? Check out www.antennaweb.org or www.tvfool.com and click on my Index page to view links to all my blogs on antennas, which has been a major part of our discussions! Just stay away from the edge of the cliff!
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