Dtv Signal Measurements

Are You Ready For DTV Transition? (The Last Minute Edition)

"Bay Area residents, are you ready for the DTV Transition?" If you watch television a lot, you may probably know those public announcements about the transition to digital television broadcasting. We have heard all those messages about the DTV Transition for years, and the date for DTV Transition, June 12, 2009, has finally come. Within few hours, the analog TV signals over the United States will become a history, TV is now entering a new milestone. Do you have a DTV converter box or a digital TV set? Even you have any of those, there're still some factors affect your abilities to watch over-the-air TV.

I have totally two TVs in my house; one is hooked up with satellite service, so there's nothing to worry about. My second one is a television set with built-in ATSC (Digital) Tuner, what I just need is an indoor VHF/UHF antenna to receive the channels. My house is very close to the San Francisco's Downtown, so with an indoor antenna, my TV can pick up most of the Bay Area's channels, except for channel 11 (KNTV), channel 36 (KICU), and channel 54 (KTEH). I know most Bay Area's channels have their transmitters on the Sutro Tower in San Francisco, but some of the channels are not. For instance, channel 11's transmitter is located on San Bruno Mountains, while the transmitters of channel 36 and 54 are located somewhere near Fremont. Technically, you must get an amplifier along with your indoor VHF/UHF antenna to receive the channels; my antenna has a built-in amplifier. The problem is I cannot watch channel 11 and 54 even I turn on the amplifier, nothing on the screen, but dark. Channel 36's reception used to be okay, although sometimes there may be a few interferences.

The real problem came out in April this year. I still don't even know what is going on; my TV cannot pick up signals from channel 36, along with channel 11 and 54. When I tune to those channels, it shows "no signal" on the TV screen. I thought that rescan the channels may help with the problem, so I tried to rescan all the channel, channel 11, the signal strength is red, which means no signal or signal is too weak. How about the other two channels, same thing happened. I also tried to rotate the antenna to see if my TV can pick up the channels, no matter how I turn, adjust the antenna, those three channels' signal strength are still red.

That is strange, and also remains many unanswered questions. Why the signal of channel 36 is weakening so much? I used to be able to watch that channel, there is no problem to receive that channel even it shut down the analog signal. (Channel 36, along with four other Bay Area channels, have already shut down their analog signals on February 17 this year) I still cannot watch channel 11, 36 and 54 at this time, so what I can do is just wait until next month when all television stations in the country are required to shut down their analog signals, to see if anything improves.

I bought another indoor UHF/VHF antenna with amplifier few weeks ago, and right now I can pick up the TV signals from KNTV (channel 11) and KTEH (channel 54), all main and sub-channels of those two channels can be received normally, picture qualities are also okay. However, at the time I write this article, I still have no way to receive TV signals from KICU (channel 36), that makes me frustrated. But the things have changed for the past few weeks, the digital signals for KICU is able to be picked up by my TV set once again, and picture seems to be stabler and clearer than before.

According to the Federal Communications Commission's (FCC) report, * there are approximately 196 stations are predicted to experience some existing population coverage losses of 2% or more, the reasons of coverage loss can be the station changes its transmitter location, the change of antenna pattern, the change of antenna power, or some combination of those factors. FCC's report also indicated that there are 123 more stations across the country are predicted to experience some existing population coverage loss of 2% because of changes in coverage and digital cliff effect. FCC identified that the digital cliff effect occurs where a station's signal is predicted not to be strong enough for reception because of many technical factors. For instance, if a station changes its channel from VHF to UHF channel, the radio propagation may not as reliable over the hills; even you are within the coverage area. People who live in rural areas may also have trouble to receive DTV signals.For the San Francisco Bay Area, there are three TV channels have the significant changes on the coverage, according to FCC.** For example, There are about 6 million people can receive channel 2 in digital format, but almost 340 thousand people who receive analog channel 2 lose their signals. If you are watching KTVU Channel 2 with over-the-air antenna, and live in parts of Sonoma, Marin, Lake, Napa, Contra Costa, Alameda, Santa Clara, Santa Cruz and San Mateo counties, you may lose your signal after June 12. If you have trouble to watch channel 2, 4, and 65 because of that, I think your only options are subscribe to cable or satellite service, or get a powerful outdoor antenna. You can go to dtv.gov to see if you are being affected by the DTV Transition, you can also check the DTV coverage map to ensure you won't lose signal after June 12.

On May 21, many television stations in the San Francisco Bay Area took the Digital Television Transition Tests in the morning, afternoon and evening. TV viewers had a chance to check whether their TV sets are ready for digital or not. Those people who saw the green screen means their TVs are ready for digital, if their TVs are not ready, a red screen popped up, and they are advised to call 1-888-CALL-FCC, or 211 to get assistance.

Here is a reminder, make sure you re-scan your DTV converter box or DTV set tonight and tomorrow as your local channels may be relocated to different channel numbers, re-scanning the channels may help you to receive more DTV channels over-the-air. If you need help for re-scanning, you can visit www.dtv.gov for more information.

* "Report - Map Book For Full Power Digital Television Stations Having Significant Changes in Coverage", Federal Communications Commission. ** "San Francisco-Oakland-San Jose - Map Book For Full Power Digital Television Stations Having Significant Changes in Coverage", Federal Communications Commission.*** "Updated Maps of All Full-Service Digital Television Stations Authorized by the FCC", Federal Communications Commission.