THE HDTV INBOX — MARCH 2008
Try And Top That
Q. Just wanted to write and mention that I enjoyed your’08 party coverage. With HDTV being more commonplace, it seems that some of the “awe” your guests experienced watching HDTV for the first time is behind us. So, how to top the experience in ’09? 120Hz, LCD for local dimming back light, 1080p front projection, Media Extender Experience with an overlay showing sports stats are just a few ideas... Fortunately there is time to think about it.
A. Yes, there is. Some of the more novel ideas being kicked around include 3D displays, an LED wall on my roof, and projection onto clouds (assuming there are any). By the way, both theaters this years featured 1080p front projectors — Mitsubishi’s HC6000 and Sanyo’s PLV-Z2000.
Do-It-All HDTV
Q. Have you heard of or do you know if there are any plans to release an HDTV with built in components for Blu-Ray and possibly 5.1 or 7.1 receiver capabilities? Basically, it would be nice to get away from all the wires and I'm not too optimistic on the whole wireless revolution.
A. I haven’t heard of any such product, and it’s not likely we’ll see one any time soon. Combination DVD player/TV sets have not been big sellers in the past, except models with small screen sizes for use on the road or in airplanes. Expecting a manufacturer to stuff a Blu-ray drive into an HDTV is asking a lot, considering the format war just ended and there is continued downward pricing pressure on all HDTV categories that would preclude the added cost of a blue laser player.
Combining a Blu-ray player with an AV receiver makes a little more sense, although that would really become a niche product in a market (home theater) where most people prefer to have all of their AV components remain separate. For now, you’ll just have to run those wires.
Cut The Wires
Q. I want to purchase a LCD TV and connect my computer wirelessly. My intent is to be able to use the HARD DRIVE on my computer to record programs like a DVR and then send the movie or program to my large screen TV in another room. I know about TV Tuner cards that can be installed in my computer and they have the software available to operate as a DVR, however, my criteria is to send a HD signal to my LCD TV. Can you give me any suggestions on what to purchase? Sony describes something like this on their website, but really don't give much information about how it works, are there other manufacturers?
A. Sounds like what you need is a wireless media player, and there are a few of those “solutions” on the market. These gadgets connect to your PC and stream the output of a media file through an 802.11 network. Check out MediaGate (http://www.mediagateusa.com/) as one possible source for product. Their wireless HD players can work with an existing PC, or you can add internal HDD storage for playback on any network.
Seeing Spots
Q. I have a question regarding DirecTV reception for the ABC high def channel in Philadelphia (WPVI-DT). Why am I seeing "green pixilation" and image break-up on my ABC high-def channel? The pixilation only happens for the ABC HD channel; other HD channels (Fox, NBC, etc.) look fine.
I've tried to contact ABC directly, but so far I've had no luck. It would almost appear as if ABC is just trying to make the problem go away by simply ignoring it. The green pixilation on the high-def ABC channel broadcasted in Philadelphia has been a problem for over two years (as I recently found out in a blog), but nobody seems to be doing anything to fix it.
I recently came across your article "Just because someone says it's HDTV doesn't mean it really is HDTV.” In it, you mentioned something about the way that WPVI-DT packs their signals (HD, SD and Doppler) into a single "shoebox"... and you argued that cramming all these signals (when there's not enough bandwidth) means that "something's gotta give, and that's the bit rate for the HD programs.” This means that image quality in the HD channel is degraded and I was wondering if this might be the cause of what other consumers in the Philadelphia area are referring to as the "green pixilation" effect.
A. Back in the late 1990s when I first set up to watch over-the-air (OTA) HDTV, I also used to see green dashes and “bursts” across the screen, mostly during a fade to black in ABC HD programs, or on images with black backgrounds. That was with my original DTV tuners (1st-gen Panasonic TU-DST50W and TU-DST51A). I had a few discussions with ABC engineering about it back then and the culprit appeared to be the station’s DTV encoder, which has long since been replaced.
Those Panasonic set-tops were eventually retired. I haven’t noticed the problem for several years now, having watched WPVI-DT on everything from integrated plasma and LCD HDTVs to front projectors with set-top boxes from LG, Samsung, and others. In fact, I’m watching the 5 PM HD (720p) newscast from WPVI while writing this, and I haven’t seen any evidence of green pixel noise coming in and out of station breaks.
I did Google the problem you described and found a clip on YouTube that appears to show MPEG break-up of the local ABC VSB signal in Sacramento, CA. This does not appear to be a station encoder problem. It looks like classic signal dropout due to low carrier-to-noise (C/N) levels, and is more likely a DirecTV head end problem. (You’ll see similar results with digital TV tuners if the carrier-to-noise ratio of the terrestrial signal drops below the minimum threshold, which is around 20–22 dB for terrestrial DTV reception.)
Since you appear to live near Philadelphia, I’d suggest you try direct off-air reception of WPVI’s digital signal on UHF channel 64 and see if the problem persists. (Any digital TV receiver will work here; you’re only looking for signal dropout.) It’s also possible that the artifacts are being introduced by DirecTV as they transcode from MPEG2 to MPEG4 compression, using whatever bit rate they feel is appropriate.
Out Here In The Fields
Q. I read your article DTV Reception Out On The Fringe, and it got me thinking about how there are a lot of folks out on the fringe like my parents who live in Poughkeepsie, NY. My parents receive all their OTA analog TV stations from a 25-year-old fixed VHF antenna (Channel Master Crossfire deep fringe) aimed at New York City. Further up the mast is a Channel Master rotor (still works after 25 years) and another old Radio Shack Yagi UHF antenna. They receive analog VHF Channels 2,4,5,7,9,11,13 and 31 from NYC and UHF Channel 23 from Albany. They are not strong analog signals, but THE picture quality is good enough to watch (some snow on VHF High and UHF channels).
I already own a DTV converter box, the Digital Stream DTX9900, and I wanted to see how it would work with my parents’ existing setup. I was very disappointed. I aimed the UHF antenna at NYC, and none of the digital UHF Channels came in (which I expected because Mt. Beacon blocks UHF signals from going up the Hudson River). I was more hopeful I would get at least one channel from Albany, NY since the terrain is more favorable. Only in the evening, WRGB-HD and WTEN-HD were strong enough to freeze and pixilate on the screen, but I never could get the converter box to lock on to a signal. During the daytime, I got a blank screen with the words "Weak Signal".
My parents don't have a mast-mounted preamp, and they don't have RG6 coax (they have foam filled twin lead each for separate UHF and VHF antennas). I just bought a Channel Master 0264DSB preamp and 50 ft. RG6 coax for a possible upgrade of their over-the-air TV antenna system this summer. Would adding a preamp help and running coax from the preamp to the TV bring in the signals from Albany, or did I just waste my money and just give up? My parents think it would be a waste of time. They ended up getting cable and told me not to bother with the antennas (they also worry about me walking around on the roof).
A. You’re on the right track with the preamp and coax solution, but it may be tough sledding. Poughkeepsie is about 65 miles from the Empire State Building (as far as I am, here in eastern Pennsylvania) and you’ve got one ridge of hills (Mt. Beacon) to clear. The same situation applies with reception from Albany — it’s almost exactly the same distance in the opposite direction, and there’s one ridge (northern Catskills) to clear.
I can pull in several New York City DTV stations from here, using a rooftop Channel Master #4308 suburban UHF yagi (discontinued) and Titan 2 7775 UHF mast-mounted preamplifier. The signals (usually WABC-45, WCBS-56, WXTV-40, and WNJU-36) do fade from time to time, but my reception path is over two sets of hills — not one, as is your case. So, it is possible you may be able to pull in these stations.
Also, remember that the minimum practical signal level for over-the-air digital TV (using 8VSB modulation) is about 20-22 dB carrier-to-noise. That level of signal would make for a very snowy picture with analog TV, but digital TV will come in just fine. Depending on your house’s elevation above sea level and the surrounding terrain, it may not be as hard as you think. According to a Longley-Rice plot I just ran on TV Fool, it looks like Albany may be the better choice for DTV reception, and you’ve indicated that some of those signals have been squeaking through.
One word about twin lead: It’s hard to believe, but twin lead has the lowest loss of any antenna wire, lower than even large (1/2”) coaxial cable! So it’s not a bad way to go for long-haul reception. But, you can’t bend it or run it next to metal objects as the line will become de-tuned and signal levels will drop. Try the mast-mounted preamp and RG-6 coax, rotate the antenna, and see what results you get this time.
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