Monday, October 15, 2007

DTV over-the-air, an inexpensive option

With more and more people buying Digital TV sets, some are confused about needing a cable or satellite service to receive the local stations’ digital channels In fact over a one week period I had two callers ask me about receiving digital TV channels over-the-air and what antenna they should get. Both wanted to get the new HD digital programs from the local stations in Cincinnati. Both wanted to know if an antenna, either indoor or outdoor, would be required.

Well, there is no easy answer. One caller noted that he lived about 40 miles north of Cincinnati. That distance places him within the potential coverage area but there are many other factors that can impact on his ability to receive DTV from the Cincinnati stations. In fact, the only way to know for sure is to actually install an antenna and see if it works. Another is to hire a technician with a signal strength meter. He or she can measure the quality of the signal and recommend an antenna. There are several models available that can work. There is absolutely no way to know “for sure” without actually installing the antenna.

Let me explain. An often overlooked by-product of the new Digital TV transmission format is the “cliff effect.” Simply put, the digital picture on your new DTV is either perfect or non-existent. With older analog broadcasting, the farther you lived from the TV transmitter the more the picture degraded, i.e. got snowy. Eventually it would be too bad to watch. With digital signals the new DTV tuner locks on to the TV signal and keeps the picture perfect until it no longer has enough “bits and bytes” of information to make a perfect picture. When that happens the picture vanishes. “It falls of the cliff.” From perfect to non-existent in an instant.

Since I don’t know if there are hills or buildings that might block or reflect the signal for the Dayton caller, there is no way of telling what, if any antenna, will work. We have two CET staff members who live in the Fairfield area of Butler County. While they live only a few blocks apart, one gets perfect reception from all Cincinnati DTV stations and the other gets none, no matter what antenna he tries.

As discussed in past posts, most people in the Cincinnati area do not receive local channels off the air. They subscribe to cable or satellite services and as such reception of local channels is part of the package. These individuals can also receive hundreds of other channels. As we get closer to the analog cut off date in 2009, more and more channels will be delivered in HD. Time will tell how many will choose to continue over-the-air only reception with the plethora of other options.

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