How do HDTV channels avoid getting noise from analog channel

[tsu]

Not to encourage anyone to try this, but, Would I be able to lessen the noise channel 3 may get from other channels if I set the per channel frequency in the service menu, maybe making channel 2 and 4 that of something further up like channel 10? This 13" crt was 32 pixils offscreen forever untill i found the factory menu code last week. I saw some channel frequency tunnings, I think. Maybe that is for RF and not AV.

[Sik]

Virtual channels forces you to use auto-scanning to find channels, which can take a while. Sometimes even around 45 minutes on some TVs.

Was this ever any different, though? I guess that over there all analog channels are/were consecutive? =/ (over here analog air channels are not consecutive, historically 2-7-9-11-13 and now 26 though occasionally there'd be some other channels around)

[zzo38]

Was this ever any different, though? I guess that over there all analog channels are/were consecutive? =/ (over here analog air channels are not consecutive, historically 2-7-9-11-13 and now 26 though occasionally there'd be some other channels around)

Analog could still be tuned directly without autoscanning though, by keying in its number. If it uses channel up/down without the channel memory it can still either you manually skip the channels that don't work or it will scan them only as you tell it to tune to them, and skip if no signal.

I would want that a TV set that can receive digital channels can have an option to disable virtual channel numbers if you do not want that feature (but still to provide it as an option).

[Drew Sebastino]

About this "autoscanning" and "channel memory", is that why it takes a long time for the TV box to boot back up if it has lost power?

[psycopathicteen]

Virtual channels forces you to use auto-scanning to find channels, which can take a while. Sometimes even around 45 minutes on some TVs.

Was this ever any different, though? I guess that over there all analog channels are/were consecutive? =/ (over here analog air channels are not consecutive, historically 2-7-9-11-13 and now 26 though occasionally there'd be some other channels around)

Are you from Chicago?

[tepples]

About this "autoscanning" and "channel memory", is that why it takes a long time for the TV box to boot back up if it has lost power?

Unlikely. Channel memory is flash. The real problem is that modern TVs run an operating system, often one with Linux as its kernel. They go to "suspend" when powered off with the remote but have to actually reboot when plugged back in. And usually the guide data for ATSC channels will be out of date, so the TV has to show a placeholder while it waits for that to come back in.

A "smart" TV (one with a bunch of included Internet streaming apps) might be able to speed up the process. After configuring Ethernet or Wi-Fi, the user would choose "Quick Scan", agree to a privacy policy, enter a postal code using the remote, and download channel maps contributed by other owners of same-brand TVs in the same postal code.

Quick Scan adds over-the-air channels available in your area.

It shares your postal code with Sambo and then downloads a list of channels that other owners of Sambo TVs in your area can receive. Finally, once you have turned off your TV, it scans for channels more thoroughly and shares the result of this scan with Sambo. By choosing Next, you agree to share this information. None of it can identify you.

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[Sik]

Are you from Chicago?

Argentina =P

[Hojo_Norem]

45 minute auto-tunes?

Web based quick tuning?

Just how many terrestrial digital TV channels do you people have?

I don't think I've seen a full CH21-68 DVB scan take longer then five and that's on the oldest and crappiest hardware I can remember.

And I've been installing TV systems as part of my job for about 12 years.

[Bavi_H]

Virtual channels forces you to use auto-scanning to find channels, which can take a while. Sometimes even around 45 minutes on some TVs.

45 minute auto-tunes? [...] I don't think I've seen a full CH21-68 DVB scan take longer then five and that's on the oldest and crappiest hardware I can remember.

For over-the-air channels, my converter box only takes a few minutes to do a complete scan. (My converter box scans through a total of 68 frequencies (RF 2 to RF 69) taking about .5 to 2.5 seconds on each one.) If you're using an antenna and your TV takes 45 minutes to scan, you might see if you can choose an "antenna" or "over-the-air" mode. If your TV is set to "cable" mode, I think it will take a longer time to scan. I think cable TV signals have a larger frequency range and a few different frequency slot patterns which contribute to longer scanning times. (Something like STD 2 to STD 135, HRC 1 to HRC 135, and IRC 1 to IRC 135.)

Just how many terrestrial digital TV channels do you people have?

Here are some counts for you.
I live in the Dallas, Texas metro area. The TV transmitter towers are 13.5 to 16 miles away.
I use a $10 indoor antenna that connects to power and has an amplifier knob on it (turned to max).

My converter box scans through:

• 68 frequencies, of which:
  • 23 have usable digital signal, which contain:
    • 77 channels, of which:
      • 48 are channels I hide. (religious, infomercials, other languages)
        02 are channels I sometimes check. (weather, cartoons)
        27 are channels I usually browse. (comedies, dramas, movies, game shows)

Note: I am counting each minor channel number as a separate channel. (For example, I am counting channels 8.1, 8.2, and 8.3 as three channels.)

You can take a look at RabbitEars Digital TV Market Listings to get a feel for other areas. (For more info: right click on a city name and open in new tab or window.) RabbitEars's "station counts" are counting only the major channel numbers. (Channels 8.1, 8.2, and 8.3 count as one station. This is like my count of frequencies with "usable digital signal" above.) They also include some "off the air" stations and some repeater stations (have // in right column). And they might assume the use of an outdoor antenna. For example, for Dallas, RabbitEars lists 37 original broadcasting stations (+ 1 repeater + 4 off air = 42 "stations"). But my converter box with amplified indoor antenna got 23 stations.

[Hojo_Norem]

Note: I am counting each minor channel number as a separate channel. (For example, I am counting channels 8.1, 8.2, and 8.3 as three channels.)

I don't understand what you mean by 'minor channel number'. Could you give named examples?

23 have usable digital signal, which contain:
77 channels

77 channels across 23 muxes. That's rather spread out compared to the 168 (TV, HDTV, radio, data, IPTV) over the 8 muxes I can receive here in ol' Blighty.

[psycopathicteen]

Unlikely. Channel memory is flash. The real problem is that modern TVs run an operating system, often one with Linux as its kernel. They go to "suspend" when powered off with the remote but have to actually reboot when plugged back in. And usually the guide data for ATSC channels will be out of date, so the TV has to show a placeholder while it waits for that to come back in.

I could understand the need for a CPU to do all the image processing, but I find it amusing that they use an OS that was made for personal computers.

[tepples]

You need an OS to run the Netflix app, the Amazon Instant Video app, the Chromecast client app, the DLNA app, etc., and Linux is free.

[Bavi_H]

Note: I am counting each minor channel number as a separate channel. (For example, I am counting channels 8.1, 8.2, and 8.3 as three channels.)

I don't understand what you mean by 'minor channel number'. Could you give named examples?

ATSC digital channel numbers are in the format of X.Y (sometimes shown on screen as X-Y). I'm calling X the major channel number and Y the minor channel number.

I thought that some people might call X.1 the "channel", and X.2, X.3, and so on "subchannels". If you're used to calling them that, you might only count the X.1 channels as "channels" and everything else as "subchannels". I was just trying to say that my channel counts were counting them all.

If an example helps, here's tonight's prime time TV listings [2-page PDF] for the channels I actually browse.

[Hojo_Norem]

I think I get it now. It looks I miss interpreted your use of the word 'channel' in that instance. I was going by the presumption that one channel = one entry on the EPG. Going by the PDF you linked, your notion of sub-channels look to be different slots on that frequency's MUX.

I guess in America you don't have enforced default EPG positioning on your TV's. Over here when you do an autotune you can pretty much be guaranteed that BBC One will be on 1 and 101 (for HD) and so on. The less mainstream channels can sometimes get shuffled around (boy, the phonecalls I get from the Panasonic owners when that happens) but the core are pretty much set in stone.