I just purchased a new Vizio HDTV (VS370E) and cannot seem to find straight answers anywhere about how to receive the HD signals. I’m in Southeast TN and have Comcast Cable. My new TV does pick up analog and digital channels, but I’m not positive the set is decoding the digital signal. The set does have a built in converter.
Anyone know? Or, does anyone know a site with straight answers?
I had a look at the specs. Your TV has an ATSC tner, so should get any digital channels that are on yor cable.
Run the auto-program function and see what it finds…
I would go to the website of your local TV stations and see if they are broadcasting in HDTV and/or what channel they are broadcast on (note: this may not match their advertised number)
Comcast (and all other cable plants I know) use QAM modulation which can’t be decoded by an ATSC tuner. You need to contact Comcast and get an HD-capable set top box and HD service. The box will also decrypt any encrypted channels which you are entitled to receive.
FYI, the connection between the HD set top and the TV can be either HDMI or component video. I recommend component video – the current generation of HD boxes don’t always implement HDMI well.
Yeah, this is about right. Comcast blows and I hate this shit.
My new TV (Sony XBR6) can find all the channels on its own and has a built in TV Guide thing that is really quite slick. It can pick out the HD channels under 13 straight out of the wall (so, news, basically), but above that it’s actively tampered with by Comcast and the TV can’t find the signal.
It’s irritating as hell to have to use the Comcast box with its horrible low resolution interface just to get CNN HD, when I know it’s something my TV could get just fine without Comcast’s interference. I keep the box around simply for occasional On Demand usage, but I don’t bother with it otherwise.
If your HDTV has a CableCARD slot, you might be able to use a CableCARD instead of the set-top box to decrypt encrypted digital channels.
Thanks for the reply.
Is it true that the cable companies have to turn the digital signal into analog to transmit it through the cable network? I was told this, but it sounds @$$ backward.
If that is true, does the ATSC Tuner decode it, back into a digital signal for DTV? Edit: Nevermind, I found my answer in a previous post above. 
I looked up the specs, too. That model number shows as having a built-in QAM tuner.
Southwest TN and Comcast here.
When I got my digital tuner equipped HDTV, there were a few digital signals that the TV seemed to suss out with its tuner. On close examination, it appeared that those were the digital signals being broadcast in the Memphis area by one or two of the local stations, anyway.
I had to spring for HD service and the HD settop box to get the full HD experience. It’s worth it for me (I’ve heard the horror stories about Comcast but they’ve not abused me enough (yet) to force me to consider moving to satellite TV), but mostly because they’re also my broadband internet provider. Basically my broadband 'net access is the one critical service I “need”; the rest is parasitic to that.
Right now, it’s mostly inertia keeping me with Comcast. I suppose I ought to research my other broadband 'net options and see if there’s not a better/faster/more reliable/more reasonably priced provider for my TV/internet services, but there’s so much to do and so little time…
Cheers,
bcg
It’s not the Comcast box that’s tampering with the HD signal, it’s the Comcast head end. They (according to rumor) do some down conversion on the HD signals provided by the networks to cut down on required bandwidth. So even if they transmitted that signal unencrypted, you’d still get their 75% signal.
No, they don’t. They may do some down conversion to save on bandwidth, but the HD signal is all digital.
You did sign up for HD service instead of regular cable, right?
Yes. I admit my concern is subjective. And, I do feel stupid running from TV to TV to compare picture quality.
Regarding the HD service, will Comcast still be able to offer it once the digital switch takes place? Will not every signal be digital?
Yes, I should have mentioned that even with QAM, you’ll only receive what’s called clear-QAM, that is, the unencrypted digital channels, which are not necessarily high-def, but are subject to having better clarity due to being digital. I think it’s a federal requirement that local broadcost channels with digital transmissions are offered in clear QAM; I certainly receive them. If I go through the lengthy scanning process, I’ll also find many, many temporary channels in clear QAM, including channels that aren’t even offered in my area! Really, Univision will pop up amongst the clear channels. If I could actually get the Spanish channels, I’d drop DirectTV and pay for additional cable (I get the $7 cable with my internet package, which would otherwise be $10 more expensive).
The thing is, even though the channels are clear QAM, they’re temporary. I’d need a CableCard or a Comcast box (and digital service) to have predictible access to them, because the cable box (or card) would virtualize the channels. That is, 101-3 may be FoodTV digital today, and 145-4 tomorrow, but would always appear as 60-1 on the cable box, regardless of where it “really” was.
Personally, I don’t worry about the digital, as the quality just doesn’t really matter to me for my limited living room viewing (the good TV), and there’s no point for my bedroom TV (analogue-only, ancient thing from 1992!).
How does Comcast rationalize requiring paid subscribers to pay more for something that IMHO shouldn’t be necessary? Granted, I’m unaware of technological restrictions, but if everything is going digital, why the cable box? Is it legitimate of Comcast to say a cable box is required or have they manipulated the technology to create a revenue stream??
My HDTV has a built-in QAM tuner. To receive digital cable, I have to tell it to search for cable, not digital ATSC.
If he has an NTSC tuner also, perhaps the OP could receive his cable through that, and get an antenna for (higher definition than cable) HDTV over the air. That’s how I have my TV set up.
My HDTV can receive digital channels without a box; it found them during it’s automatic setup. I didn’t even know they were there.
The only problem is that they have weird channels like 98.804 or 108.10. Yes, there is a decimal point in there (and the TV remote has a . on it too). It’s a bit of a pain to tune to them and I’ve never found anything to tell me what is where without looking at the channel to figure out what it is, but they are there and accessible.
Is it SUPPOSED to be that way? I get annoyed with my local channels moving around on me like that.
-Joe
My TV does something similar, but it’s not quite that stupid. I’ve got SD on channel 5, HD on channel 5.1, for example. It’s also got a neat feature where you can reassign channel numbers to whatever you want, so I could eliminate SD channel 5 entirely and put HD 5 on 382 if I felt like it.
I’d expect you’re not stuck with 98.804 (which would be really lame, I agree). Do you not have any way to change them?
Comcast is no different in these aspects than most any other cable company in the US.
HDTV and digital TV (or digital cable) are not the same thing. You can have SDTV transmitted digitally. The “digital transition” will not necessarily impact how cable TV signals are delivered at all - only over the air broadcast TV is necessarily impacted.
Your TV’s ATSC tuner capability is useful for picking up digital broadcast TV (with an antenna), both SD and HD. The NTSC tuner capability is useful (for a short time only) for picking up analog broadcast TV (no HD), and also for tuning analog cable signals (even on a digital cable service - channels below about channel 80 are normally transmitted in analog by the cable company). The QAM tuner capability is useful for picking up digital cable that is transmitted without encryption. Cablecard enables QAM tuning with decryption as well.
Not all HD is the same. Not only are there two major competing broadcast TV formats, 1080i and 720p, the signals can also be compressed (by the local broadcast station, or the local cable company).
Some/most HD channels on digital cable are generally encrypted. Cablecos and the content owners are trying to minimize piracy (unencrypted, it is trivial to record HDTV onto a harddrive). The Cablecos are also trying to minimize competition from standalone “time-shifter” boxes (TIVO without the fee), and to maintain the benefits of of their own HDTV DVR offers.
Some channels are offered without encryption, most notably local broadcast channels, not because the Cablecos are nice, but because they are required by the FCC to do so. Further, Cablecards are also offered only because the FCC mandates that they do so (in a poor attempt to force competitive alternatives to things like TIVO and Cableco DVRs). Unfortunately, the cable industry had their hand in writing the FCC requirements, so the Cablecard benefits are far from clear to date.
In my experience with Comcast, their unencrypted QAM is significantly compressed. I get the best HD picture by using the ATSC tuner with an antenna (for some channels, this antenna can be a decades old pair of VHF rabbit ears).
So, if you are in the broadcast range of Chattanooga, or Knoxville, try disconnecting your cable altogether for a moment and plug in an antenna (even old rabbit ears, though there are benefits to the new “digital TV” antennas - see antennaweb.org for more information).
Any clear HD signals you get from that setup are likely to be better than anything you can pull off of Comcast. Without any cable box, and the basic cable option, you should be able to get the basic cable (analog) channels AND the clear-QAM local broadcast channels (even HD). To get the “premium HD” channels (like ESPN-HD, Discovery-HD, HBO-HD), you will need a Comcast HDTV cablebox (or Cablecard). To get digital cable channels (channel 80 and up), without premium HD, you will need a standard cablebox (and an enhanced channel package service).
Hope that helps.
Yup, it’s supposed to be like that, because you’re not supposed to receive your digital channels that way. Cable companies want you to rent a box or CableCard, which would keep the channels where they’re supposed to be in the lineup. In a way, it’s cheap security, since you can’t count on the channels always being there, and they don’t have to waste resources with encryption. There were reports of people receiving their neighbors’ pay-per-view programming via this method (only temporarily, though, until the stream changed). A box or CableCard would have been smart enough not to tune the channel.
You’ll note, though, that the “required” digital channels stay where they’re supposed to be.