What is the difference between a smart antenna and a regular one?

How do antenna TV channels "work" now? How do I find & add new ones?

• I've been cable-less for the past few years and have been using antennas with my HDTVs for TV reception and have been very content, except I really have no clue what I'm supposed to be doing. To wit: Adding Channels & Channel Scanning: In the analog world channels were whole numbers, now all channels are "tenths", one decimal place over- i.e. 50 vs 50.1, 50.2, 50.3, etc.... In the old regime I might not know if I could get channel 50, but I knew that I could just check it then 51, then 52, etc... -How do I check for channels now? Do I have to roll through all of the 10th channels individually? Is there a way to do this without a channel scan? -Doing a "channel scan" might detect new channels, but it also might purge any channels (especially manually tuned ones) that are not coming in well at that moment. Or do modern TVs auto-add & remove channels? -One of my antennas requires fine tuning to receive various channels; when setting it up do I have to to a "channel scan" with the most "popular" setting and then go back and add all other channels individually, going through the different antenna settings? -How do I know when & where new channels get added? Do I have to constantly check http://www.antennaweb.org? -There are two analog stations that come in extremely poorly, one in Spanish. I thought all analog stations were forced to shut down under penalty of large fines? -It seems that the tuner in the TV itself makes a huge difference for reception; when I swapped out an older higher-end Panasonic TV with a newer but cheaper Toshiba I went from having 18 channels to 7, even though they had the same antenna and setup otherwise. Is there a way to boost this?

• Answer:

  The channel scan works a lot like the old cable-ready TVs that would scan all the channels and then only make the ones with signals available to you. The TV tunes into every channel from 2 to 50-whatever that they are using now, and looks for a signal. Now, in the digital world, each signal isn't just a single program like it is on cable or old analog TV. Each physical channel is a stream of data that can contain any number of video programs, as well as a chunk of data that informs the TV's tuner about the channel and the programs. So what happens is that your TV scans through all the physical channels, and eventually finds one on say channel 10. It starts listening to that data stream, and one of the chunks of data tells the tuner "hello, I am channel 10. Display me as channel 5. I have three programs going now, channels 5.1, 5.2, and 5.4. Additionally, I have a channel 5.3 that you should show on your guide, but it's off the air right now." The TV notes this and moves on to the next one. Some of what you ask depends on your TV. It might not display that channel 5.3 because it doesn't want to confuse you. So you'd have to re-scan once that channel goes on the air. Some TVs will let you enter in the physical channels directly, and it will add anything it finds to the list. Others won't, and you have to rescan everything. So, the the sub channels, the .1, .5, whatever, is completely up to the whims of the broadcaster. There was a channel by me that had something like 7 sub-channels, all full of nothing but infomercials. You need to re-scan when a broadcaster changes. Sometimes a channel's main transmitter might get moved to a new channel. The TV thinks it's on 43, but it moved to 13. SO you have to rescan so the TV can discover where it is now. As for still receiving some analog channels, I believe the FCC has an exception for ultra-low-power channels.