OTA HDTV Reception Q&A

Updates on the DTV transition and how to receive over-the-air digital television for free.

Location: Richmond, IL, United States

Hello there! I created this blog to share the information about over-the-air HDTV reception you have been wearily searching the Web or calling technical lines for, whether you have decided for less expensive means to get your favorite TV shows, or still adjusting from the over the air broadcast DTV transition that occurred on June 12, 2009. After working for a leading antenna manufacturer for almost 5 years, during which time I've shared my expertise with those who asked on the phone and by email at work, I decided to do the same in the Blogosphere! Confused about getting your local HD channels? Just click through the archives, some of the most useful information is in the early posts from 2005-06. If you want to get in touch with me with antenna related questions, just leave a comment anywhere on this site.

Thursday, April 19, 2007


One month ago, I moved out of Iowa and relocated to the Chicago area, taking my HP Media Center PC with me. Because I was in a new area, I of course needed to reprogram my electronic program guide in Media Center for the over-the-air DTV channels in the new market. With the antenna as optimized as possible, I began updating my PC for my new area so I can record my favorite broadcast networks shows digitally and over the air to enjoy on my own time. I found that this was not a quick fix, and that with an automatic scan for my northwest suburban location, I was even getting listings for the local stations in Milwaukee, Wisconsin, which I could not pick up with the antenna I have. I should mention that my PC uses Windows XP, and not Vista, and I have no plans to upgrade at this time, only because I think Vista will take up a lot of disk space that would reduce the amount of DTV recordings I can keep.

Fortunately, I was able to browse posts on a site, www.thegreenbutton.com, where registered users can share ideas and issues using Microsoft Media Center. I find out through the posts that the electronic program guide (EPG) in Media Center calls on XML files for the guide listings. The files are located in this directory, assuming C: is the location of the operating system software:

C:\Documents and Settings\All Users\Application Data\Microsoft\eHome\EPG\prefs

In order to access this directory, you will need to be logged in with full administrator privileges with the ability to view hidden directories. The folder contains two XML files of significance: atscchannels.xml, which maps the digital channels to the FCC-approved "frequency assignments", which you can find using www.antennaweb.org. The other file, atscprefs.xml, lists the multicast "subchannels" that the station broadcasts in addition to their primary channel. I found that the easiest method to fix my EPG for the new location would be to delete these XML files, and just manually add them in the "Settings à Guide" section in Media Center. However, I do recommend renaming the current XML files, adding "old" or some dummy name or extension for backup purposes.

I was aware of the available sub-channels from the Chicago broadcasters using the direct antenna input of the HDTV set connected to my Media Center PC, and their frequency assignments, so that information allowed me to manually enter the digital channels into the program guide. I started by configuring my tuners for a cable tuner and a digital TV tuner. Now while my cable tuner is analog, I could still select the digital cable listing from the local provider for the electronic program guide, which updates via the Internet and NOT the cable company. You don't even need to have a cable connection to the tuner for this to work. This is significant since most of the over-the-air multicasts are available on digital cable in my area, although I am not sure at this time if the FCC has enforced "must-carry" of all local multicasts on digital cable. The disadvantage is that is takes a bit longer for the guide to update because there are more data to download.

After setting the guide to download the digital cable EPG, I essentially deleted the XML files used for the off-air digital TV listings. By doing this, Media Center is now missing the digital TV information, and I could now manually add the channels. The Guide Settings has a function, "Edit missing digital channels". By selecting this, I can choose the option "Add missing DTV channel". The first time I enter a channel ID, I enter the primary channel first, for example, 2-1 for CBS 2 Chicago. With Media Center not aware of this channel in the XML file, it creates an empty atscchannels.xml file entry, and Media Center asks for the frequency assignment where the digital channel is located, in CBS 2 Chicago's case, channel 3.

As I manually load the channels, I also add the sub-channels. Once a primary channel is set, Media Center automatically maps to the frequency assignment for additional subchannels. After loading all channels, I can now use the "Edit Digital TV Listings" setting in Media Center to map the off-air digital channel to the digital cable listings. For example, in Chicago, PBS affiliate WTTW has four channels in its digital multicast, but 11-4 is not yet available on digital cable, and I do not see myself watching it much anyway, so I opted NOT to add 11-4 while programming the guide. I had to be tricky because 11-1 is an all widescreen channel with HD programming while 11-2 is the digital simulcast of the traditional Channel 11. 11-3 carries the all-how-to channel, Create. So, I had to map 11-1 with WTTW-DT on the digital cable listings, 11-2 with analog cable 11, and 11-3 with WTTW-DT3 as identified on the digital cable listings. Once all this was completed, I could now use the Media Center EPG to set up recordings for the right shows on the right off-air digital channels, a big help. Sadly, Media Center in XP does not use the EPG metadata in the PSIP tables loaded by the broadcaster to update the guide listings; you will need to rely on the available digital cable listings.

Consequently, I fear that after February 17, 2009, I will need to manually reprogram the EPG yet again when some of the local broadcasters switch their digital over-the-air transmission on their FCC-approved final DTV assignment, which for some channels will be different from their current assignment. Since I will know what the new assignments will be post-transition, I could simply just go into the atscchannels.xml file and change the channels right there, and that should be it. Otherwise, I will have to repeat the process I just described yet again. I also hope that if my cable company reassigns the digital cable lineup that Media Center will automatically map the off-air digital TV listings to the channel ID and not the new channel, else I will have to fix THAT change in Media Center manually.

In related news, HP announced in late March 2007 that they would be discontinuing their high-end Digital Entertainment PC line, which will leave Sony as the only manufacturer of note of Media Center PCs acting as servers for the living room, home theater, or control unit in a rack for an electronic home with a structured wiring network. It would seem to me that HP, which has been making a huge comeback in the consumer PC market, is focusing its strategic plan on the common consumer, and since the release of Vista, I think HP feels that homeowners can simply use a laptop or desktop PC on a home network to record off-air digital programs, and rebroadcast them on the home network to other PCs or Media Center Extenders, like the Xbox 360. In addition, HP has released a PCMCIA digital TV tuner card for its Vista-based laptops, and with high-capacity external USB hard drives of over 100 GB becoming more affordable and easier to put on a home network, educated homeowners could very easily custom-make a digital entertainment network on their own budgets and capacity without having to shell out over $2,000. So, I would speculate that HP is foreseeing an unprofitable low demand for their "DECs" as they know them. In addition, Vista allows such PCs to be Cable-Card friendly, which would easily allow such PCs to decode and record digital cable channels for subscribers, thus allowing that content to be streamed on a home network. These trends will further allow middle-income households to make their homes connected and share content. Who knows, well-designed home networks could pretty much allow, in the right area, one indoor antenna connected to one networked PC to distribute off-air DTV programming all over the house.


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