For the last 10 days I've been watching a rare bird - a standard-definition digital television, or SDTV. It's the no-frills set of the future for the nearly 20 percent of American households that get their TV the old-fashioned way - over the air.
You haven't seen many of these, because TV makers have been concentrating on big-ticket, high-profit, high-definition (HD) sets that most buyers hook up to cable TV feeds.
But high-definition video is only part of the spectrum as the country moves to a new digital broadcasting system. TV stations are already broadcasting in several digital formats, including one called standard definition (SD).
This looks a lot like today's analog TV and doesn't require expensive HD electronics - only a relatively inexpensive digital tuner. Until now, TV makers didn't want you to know about this. But starting March 1, the government will require over-the-air digital tuners in all sets with screens 25 inches and larger. The 27-inch RCA Model 27F524T I reviewed has both digital and analog tuners - something you should demand in any over-the-air set you buy over the next three years.
Here's the good news. With over-the air broadcasts, the $339 RCA set produced a picture that was crisper and clearer than today's comparable analog sets. It was also slightly better than a good analog set hooked to a cable feed.
The industry calls this "DVD quality," and that's a good description of what you get. It's not quite high-def, but it might be all you need, particularly with a screen smaller than 30 inches. As my wife says, "I don't care about seeing every pimple on Alex Trebek's face."
Now the bad news. I couldn't get a usable signal from some stations with the set-top antenna that RCA provided. And I live on high ground less than 8 miles from Baltimore's Television Hill, and even closer to Maryland Public Television's towers in Owings Mills. I also couldn't get Washington stations, as I can with analog broadcasts. I don't know how other sets in this category will fare, but they'll probably need a rotating rooftop antenna.
If you're even thinking of buying a set over the next few years, it's important to know something about the continuing switch from analog to digital broadcasting because the industry is dumping as many obsolescent analog sets on the market as it can.
It knows these sets will be useless for over-the-air broadcasts starting Feb. 17, 2009.
That's when Congress says broadcasters must cease analog transmissions. Local stations are broadcasting both kinds of signals now.
But after the deadline, the only way to get an over-the-air broadcast with an analog TV will be to buy a converter box and possibly a new antenna. Which, of course, the industry will be happy to sell you.
If your TV is hooked up to a cable or satellite feed, you don't have to worry about this - the cable company will provide the signal you need. But the switchover will affect any sets in the house that depend on broadcast signals.
To protect unwitting consumers from buying obsolete junk right up to the deadline, the government is requiring digital tuners in all larger sets manufactured after March 1.
So it was that I got to try out the new RCA 27F524T a few weeks early. RCA offers three similar 27-inch models with slightly different features, at slightly higher and lower price points, as well as a 32-inch version for $599.
The set has two coaxial antenna inputs and two tuners - one for standard analog broadcasts and cable stations, the other for over-the-air digital broadcasts. RCA provided me with an amplified "rabbit ears" antenna, which I plugged into the digital input.
Like most modern TVs, the RCA has a setup routine that runs through the spectrum (analog and digital), looking for live stations. That's where I got my first nasty surprise. The Baltimore area has three VHF and five UHF stations, but the set picked up only three out of the eight.
Trying to tune the others manually resulted in a blue screen with an "Unusable Signal" message. So I jiggled the rabbit ears and ran the setup again. This time I picked up three more stations but lost one I had the first time.
Frustrated, I ditched the new RCA antenna and plugged in an unamplified, four-year-old RCA model of a different design that I found in the basement. Oddly enough, that worked better. Even so, with another hour of twiddling the rabbit ears and re-running setup, the best I could manage was six stations out of eight.
Another problem: the so-called "cliff effect." With an analog tuner, you can watch a weak or snowy signal if you really want to - which is how Washington stations often appear to Baltimoreans.
Digital tuners do not tolerate ambivalence - for the most part, you either get a great signal or you get zip - sort of like falling off a cliff. The only Washington station I was able to tune in with the rabbit ears was Channel 9, and that lasted for only about 10 minutes, until the voodoo expired, I guess.
Digital TV also requires more patience than adolescent males of all ages are likely to possess. The RCA set took four seconds to change channels, which isn't unusual, according to George R. Beneman II, vice president for technology at Maryland Public Television, who watches TV over-the-air at home.
"I guess you can say there's no such thing as channel surfing any more," he observed wryly. "The TV essentially has to reformat itself every time you change channels, and that takes time."
I called Beneman because MPT is one of the nation's leaders in digital broadcasting. It's the only local broadcast outlet that takes full advantage of the most exciting feature of the new system: Each station can now broadcast separate programs on up to five sub-channels.
From 8 a.m. to 4 p.m., MPT has additional channels for kids, families and classrooms. In the evening, its main broadcast and high-definition channels often have different fare. It takes time, effort and money to do all this, and MPT obviously understands what the new digital medium is about.
Elsewhere, additional digital programming is thinner. Most stations use the new bandwidth to broadcast two versions of their main programming, one in the standard 4:3 ratio of analog TV and the other in a "letterboxed" version of the more rectangular format that digital broadcasters prefer.
WBAL (11) and WMAR (2) have added 24-hour weather channels, while WNUV (54) offers an additional channel of entertainment, mostly music.
Merely tuning a digital set will require new habits. Technically, digital broadcasts use a new set of channel numbers, but the industry and FCC didn't want to confuse current viewers. So they set up "virtual channels" that allow each station to keep its old channel number, with subchannels for multicasting.
If you punch in a channel number on the remote control, it shows up in an "X-X" format on the screen. For example, MPT's broadcasts will show up here as 22-1, 22-2 and so on. This will take some time for people to figure out.
Bottom line: The first low-end digital TV that I tried produced an excellent picture - when I could get a picture at all.
Once they have enough over-the-air viewers, broadcasters will undoubtedly be able to tune their transmissions better. But if even a fraction of their viewers have the same trouble I did, they'll be marching on Washington with pitchforks and axes, trying to find the culprits who stole their perfectly good TV signal.
http://www.baltimoresun.com/technolo...ck=1&cset=true 
Linear Mode
