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

March 12, 2013 9:34 AM

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 AntennaWeb?
-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?

posted by Challahtronix to technology (5 answers total)

I believe the whole numbers still denote frequencies. The 'tenths' digit denotes sub-programs carried on that frequency. With digital broadcasting it is possible for multiple programs to be carried on a frequency. EDIT: Oh, and the number of subprograms on a channel will be updated automatically if it changes.
posted by DarkForest at 9:51 AM on March 12 [1 favorite]

For us, we ran the channel scan and then manually removed and added channels. It is winter here and we tended to get better reception after the sun went down in the winter than during the day, so that was when we did the best channel scan. Trying this in the summer gave us a lot fewer channels.

This wasn't bad for us because there are less than 30 channels available in our area. YMMV if you live much closer to a much bigger metropolis.

I guess I never thought there'd be more channels added, but again, I'm in a possibly smaller market than you. If it's a good signal night and I just push the channel up button, the TV may occasionally find a new station and add it. And, if it's a bad signal night, it might automatically remove a station it has no signal for. Does your TV have "favorite channel" buttons? Maybe add some of your iffy stations to those so that if they do come in for you unknowingly, you can try hitting the button.

There was one analog channel that we got reception for - a bible network. We just manually removed it.

I've only had the one HDTV so I don't know about the differences between tuners. We did get an external signal amplifier that is hooked up to our antenna through Denny's Antenna. Their site is old school HTML but had a lot of helpful information on it when choosing what kind of pre-amplifier would work for us. Big important pointer: more signal boost is BAD if you already get a good signal. More != Better, as it will blow out the good signals. So you have to find a good amplifier that will give you just enough boost without boosting it too much.
posted by jillithd at 9:54 AM on March 12 [1 favorite]

This won't help with added or changed channels, but I had all kinds of signal and reception problems and the antenna that ended up bringing in the most channels was this one I made from cardboard and tin foil. Bonus: I bought the balum connector at the 99-cent store.
posted by Room 641-A at 11:13 AM on March 12

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.
posted by gjc at 8:37 PM on March 12 [2 favorites]

The low power analog channels will stop working on September 1, 2015.
posted by mmascolino at 1:25 PM on March 14