Why do digital televisions have more than one channel like 7, 7-D, 7-S and why do they have different shows on

Question

Sometimes all the channel 7's broadcast the same show, sometimes one is a weather channel. Sometimes channel 11 has 4 different channel 11's all with different shows and sometimes they all are broadcasting the same show. When they are different, sometimes we can't see one or two of them because the picture is pixilating and the sound doesn't all come through.

Answer 1

The digital channels can be sub divided into "sub channels".  Each sub channel can be independently programmed.  The number of sub channels depends on how much the broadcaster wants to devote to it.  I've seen as many as six SD sub channels with no ill effects except maybe reduced resolution.  

HD sub channels take up more resources so usually there is only one HD and one or two SD sub channels.  Setting this up is a bit of a technical balancing act.

When you see the same thing on two different sub channels, chances are one is SD and the other is HD.

I hope this helps.

Answer 2

This is Because with digital tv they can fit more channels on the section the one channel took up before so television stations can broadcast multiple channels on the same signal

Answer 3

The broadcasters are taking advantage of the additional bandwith that digital television provides.  The analog signals will  stop in February 2009.  The broadcasters can fit 4 digital channels in the space of one analog channel.  The quality of the different channels probably varies because of your antenna.  The digital signal is broadcast over UHF, which requires a different antenna than VHF.  An analog signal will slowly degrade and get snowy as the signal decreases.  Th digital signal is either there or not there.  The pixilating can be the result of a poor digital signal.