The CEA site that assists with antenna selection is technically geared towards outdoor antennas, but provides useful information relevent to indoor antennas as well. It's a simple concept: you provide your street level address and a few answers about your home's structure. The CEA provides you with a street level map and compass directions to aim your antenna at the free, digital signals available to you. If you purchase a directional antenna, the provided map comes in handy. Consumers with an omnidirectional antenna don't have to worry nearly as much about the "aiming" factor.
Here are the results for my zip code:
You can see that most of the DTV signals are due south of me; useful info if I have a directional antenna. Also noticable are the channel numbers available to me. Local DTV signals are sent over unused UHF signals. Yes, these are the same UHF channels you might have watched years ago if you could see through the "snow" of poor signal reception. With DTV, the snow has melted. You either get a perfectly clear picture or no picture at all due to signal loss.
So now we have some directions to aim at and we have some channel numbers. What's next and what do the channel numbers really mean? The CEA-sponsored site has the answer. Again, based on your street location, you get detailed results of which channels are owned by which broadcasters. A clean, easy-to-read table is provided that tells you which network is on which station; the table is even sorted by distance to your street; from closest to farthest:
Here you get the station's call-letters, network and channel for your tuner. Some channels are "multi-casting", meaning that they are sending multiple, unique programming on sub-channels. In my area, for example, ABC's main programming is on channel 6.1, while channel 6.2 is used to provide non-stop weather and doppler radar.
So now you know who is broadcasting and from where. How does that help with antenna selection? The final piece to the free HDTV programming puzzle is in the colors on the chart above. Each color corresponds to a standard antenna type. You decide what channels you will try to pull in and then pick the lowest channel or color on the chart. Keep in mind: the lower you go on the chart, the larger the recommended antenna is likely to be.
The colors on your personalized channel chart correspond to the colors on the standard Antenna Selector graphic. To make things easier for consumers, most antennas have this graphic on their packaging, so if you do your homework, you can shop for an antenna with a certain level of confidence. The right antenna completes the HDTV package and can provide you hours of free, detailed programming.