Originally Posted by RobJJ
How do you tune in a channel such as 7.1 (the website says is uses frequency assignment 26. Does that mean if I simply tune in to channel 26, I should receive that channel?
Stations broadcast their analog and digital signals on different channels. From the example you gave, it sounds like you have a station that broadcasts its analog signal on channel 7 and its digital signals on channel 26. All digital TVs and STBs are designed to re-map the analog channel numbers to the digital channels so that once your TV/STB knows about your example station, you can tune it as channel 7 even though it's reallly on channel 26. Broadcasters insisted on this because they've spent so much money on marketing based on their analog channel numbers. (One of my local stations would not be happy if they had to change their slogan from "Your Friend Four" to "Your Friend Thirty-Six"! :eek: )
The TV/STB finds out about the channel remappings in one of two ways: (a) you tune the station for the first time by giving the digital channel (26), and the TV/STB picks up the analog channel number (7) from information (PSIP data) encoded in the data stream; or (b) you tell the TV/STB to do a "channel scan" which automatically finds all the digital channels and extracts the analog channel numbers from them.
Channel numbers like 7.1 come in because a single channel can carry more than one digital signal (multicasting). Many stations have a weather radar, weather channel, or SD simulcast of their HD signal, along with the main HD signal.
Most stations use UHF channels for their digital signals, even the ones that use VHF for analog. There are some exceptions, though. For example, one station near me in Columbia SC uses channel 25 (its traditional channel) for analog, and channel 8 for digital. So you need to find out whether your digital channels are all UHF, or whether some are VHF, because that determines whether you can use a UHF-only antenna, or need a VHF/UHF combo.
As an added twist, after the big analog shutdown (which now looks like it's going to happen in April 2008, although it's not final yet), some stations will move their digital signals back to their former analog channels. This is especially likely if the analog channel is in the high-VHF range (7-13), because VHF propagates better than UHF with less power, and high-VHF has fewer problems with interference than low-VHF (2-6). So in your example, you may end up needing to receive channel 7 after the analog shutdown, in which case you may want to get an antenna that can handle VHF, even if you don't need that capability right now.