• Virtual vs. Real Channels



    With the change to DTV
    we ended up with "Virtual" Channels what are these?

    The "real" channels are the channels the TV stations are using to transmit on. Back before HDTV, the channel number told us what frequencies the TV station was using. We became so used to the channel number being the be-all and end-all for a TV station that the FCC or the broadcasters (TV stations) thought we'd get really confused if all of a sudden ABC Ch. 7 changed to ABC Ch. 32. Thus was born the "virtual" channel number. Also, since a digital signal can carry more than one program at a time, we got the added advantage of having more “channels” per channel – more programs per 6MHz frequency bandwidth. Thus the use of the decimal, as in Channel 8.2. So the use of the decimal, or dash, to designate a virtual channel (program) within the basic channel (frequency bandwidth) came about. The “virtual” nature of the channel number is twofold: one, it designates the channel number we remember from before HDTV and, second, it designates, with the decimal or dash, a different program within the channel to watch.

    This was all done in order to keep everything familiar to us. In a move that would not force us to learn new channels for our favorite stations, it was decided to, in some way, keep the channels familiar to us. So, even though the TV stations had to change the channels they used to transmit their signals on, the stations could keep calling themselves by their old channel numbers.

    These channel numbers, if they are different from the channels the stations are really transmitting on, are now called the "virtual" channels. As mentioned before, the "real" channels are the actual channels that the stations are transmitting on.

    The web site TVFool.com is one of the sites where we can see the use of both virtual and real channel numbers, and learn which stations we should be able to receive:



    The above is just a part of the report TVFool generated for me, but it’s enough to show the Callsign, Real, and (Virt) channels.

    There are a few stations which did not change channels when they went to HD broadcasting so their virtual base and real channel numbers are the same. In the Washington, D.C., area, channels 7 and 9 are real channels for these stations, and these were the channels they used before the changeover. It is the same in Baltimore, where channels 11 and 13 are still the channel numbers for those stations and their transmitting channels.

    If you want to know more about the real channel numbers, you can look them up on any number of sites. Wiki is a good one for being able to find the frequencies associated with a channel number as well.

    More reading:

    Search for stations near you and their virtual channel numbers and their real channel numbers at TVFool:TV Fool

    Find out about any station near you using the FCC site: FCC TV Query

    Virtual Channels:

    See the wikipedia article about Virtual channels

    Here's the wikipedia page about REAL channel numbers and their associated frequencies: Television channel frequencies

    Please note that this is just a quick listing of the possible sites you will find. For instance, TVFool is not the only site that will generate a report for you based on the height of your antenna and the stations it might be able to receive.

    If you find a site you really like that helps you set up your antenna, please take the time to list and explain it here so we can all try it out. Thanks!


    All my blog articles are listed at: Karras' Corner
    or
    Karras' Corner Article Links on my KE3FL web site.

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