I recently purchased a Olevia HDTV and I am using Comcast Basic Service.

After the initial scan I found a few of the Comcast channels have subchannels- example cable 3, 3.1, 3.2 and HD is displayed on the HD subchannel. Other Comcast channels simply display Cable 5, 6, etc.... on the TV. It appears (?) I am getting HD content on some of the regular channels and what I am trying to understand is:
If the comcast channel/programming is HD, will the tuner display HD when switched to that channel, or
Are HD programs broadcast only on the subchannel (remember I only have basic service)

Thanks for your help.

No cable box with basic service

When you did a channel scan you found all analog (#) and digital (#-#) channels available via unencrypted QAM. Note that channel 3-1 is not a subchannel of channel 3. The fact that both start with "3" is technically coincidental -- they're frequencies are not necessarily related to each other. A technology (PSIP) helps map the actual frequency of 3-1 (which could be actually broadcast on 89-1) to the "friendly" channel number that you'll see in program guides (3-1).

HD will, of course, only appear on digital channels. Not all digital channels are HD, however. Typically, when there are multiple sub-channels, the "-1" sub-channel is the HD channel, but that is NOT always the case. (Here in Boston, 2-1 is digital SD, while 2-2 is digital HD, for example.)

I hope I answered you question.

Thanks for your reply and now it makes sense with the PSIP protocol. QAM (I understand modulation) is analog, so does that mean all Comcast broadcasts are analog under basic service? that would mean an HD carrier is converted and delivered via cable and then reconverted by the TV? In a pure digital world, one would use a PSK type of modualtion scheme. I'm trying to make some sense (no cable background) of how both digital and analog signals are managed bythe carrier and how the TV tuner manages the signals. Please- not to go off on a heavy tech discussion but I guess i need to read up on the technologies. Thanks again

QAM (I understand modulation) is analogQAM can support either analog or digital. In this case, we're talking about digital, not analog.

QAM stands for "quadrature AMPLITUDE modulation", not "quadrature analog modulation"! The only use I know about of QAM modulation for analog is AM stereo radio (does anyone even know that it exists? It just barely exists, but it does exist!".

I recently purchased a Olevia HDTV and I am using Comcast Basic Service.

After the initial scan I found a few of the Comcast channels have subchannels- example cable 3, 3.1, 3.2 and HD is displayed on the HD subchannel. Other Comcast channels simply display Cable 5, 6, etc.... on the TV. It appears (?) I am getting HD content on some of the regular channels and what I am trying to understand is:
If the comcast channel/programming is HD, will the tuner display HD when switched to that channel, or
Are HD programs broadcast only on the subchannel (remember I only have basic service)

Thanks for your help.



Remember you are only getting HD channels that are being broadcast over the air (OTA) not from you cable. Those HD programming over the cable are encrypted and you definitely need the cable box to receive them in your TV.

Thanks for your reply and now it makes sense with the PSIP protocol. QAM (I understand modulation) is analog, so does that mean all Comcast broadcasts are analog under basic service? that would mean an HD carrier is converted and delivered via cable and then reconverted by the TV? In a pure digital world, one would use a PSK type of modualtion scheme. I'm trying to make some sense (no cable background) of how both digital and analog signals are managed bythe carrier and how the TV tuner manages the signals. Please- not to go off on a heavy tech discussion but I guess i need to read up on the technologies. Thanks again

Since you have an understanding of modulation, the Qam modulated channel is digital, this is simply the method to get the signal from point A to point B,what it carries (signals) can be digital or analog, your TV or STB will demodulate the channel (TV will only demodulate unencrypted QAM channels).

Since you only subscribe to analog cable unless there is a physical filter in line the digital channels are also there, your TV is capable of demodulating some of those channels.

Local affiliates of broadcasters are carried in HD on Cable unencrypted. So you can get say fox HD for free with basic service.

He can get all local channels that are broadcasting in HD free over the air (OTA), so he does not need basic cable for that .

I'm sorry to necro this old post, but I've been searching for info on getting HD on ComCast basic and this thread popped up. No no sense in starting a new thread when this one is already here.

Here's my (very newb) question. I have ComCast Basic cable. They gave me a non-HD set top box. They're telling me that if I want HD channels, I'll need an HD set top box and pay an additional $20 / mth. That sure seems like a rip off to me since I *should* be able to get local HD channels for free. The question is, can I get those local HD channels for free while using a non-HD set top box?

My TV is a Samsung LN-4671F, so it has multiple inputs. Would it be possible to split out the input and run one input into the back of the set top box and another into a different input on the back of the TV?

I know, I know... these are probably very newb questions... but hey, I'm not ashamed to admit I'm a newb.

Thanks for any input,
Max.

You can get HD local broadcast channels using your own QAM tuner, such as the one in your Samsung television. All the outputs on the TiVo are active simultaneously.

Max,

You will quite likely have several HD feeds available to your Samsung tuner! Just put a splitter to the wall with a feed to "cable" RF on the TV and feed the Comcast "set top" to another input on the set. You can then just do a "channel scan" and you will end up with probably 100+ detected and on a Samsung I think you need to go back through them and select the ones that display an image. You will be pleased I'm sure with your results!

Do a search here for your zip code and you'll get a pretty good idea of what to expect!

http://www.silicondust.com/hdhomerun/channels

Wow! It says there are 90 digital cable channels in my zip code! I can't wait to try this out. Sure looks better than paying an extra $20 / mth for something I'll use very little.

Thanks for the reply. I'll get back to you with the results soon.

Max.

OK, reporting back. I got a splitter and ran 1 cable directly into the "Cable" input on the back of the Samsung TV and then did a channel search. It found several digital channels, but there are only 2 that are true HD... 2-1 and 80-2.

When I put in my zip code (77024) in the link above to see what channels *should* be available, I see multiple HD channels in the range of 86-1 to 89-3. The problem is, even when I go to my TV's menu and tell it to list ALL channels, not just those found by the scan, there are no channels in that range. It skips from 81-3 to 90-1... and neither of those are working channels.

How do I tell my TV to watch the channels in the range from 86-1 to 89-3?

On a separate note, I also have an Akai 720p TV in the bedroom with no cable box. It has an ATV input and a DTV input, but when I run a cable into the DTV input and tell it to scan, it doesn't find anything. It's strange, though, because it only goes up to channel 69 and then says it's 100% complete. Does that make any sense? Maybe it doesn't have the right kind of tuner?

Thanks for all the help so far.

Max.

I believe for the Samsung to "scan" properly" the cable from the splitter needs to go to ANT 2 on the TV. I've used a Samsung "tuner" but don't have a similar TV to yours. I've since sold my tuner and use TiVo's as "set tops"! I recall though that there was something "unusual" regarding the connections. You use what from your cable "set top" to the TV?

See pages 15 and 38 in your owners brochure!!!!

Just had a wholly unuseful chat session with a Comcast 'rep' - my belief that they get NO training has been upheld!! So... we have the Comcast HD-DVR and record shows on both tuners at times (like Mondays)... before we got the Samsung, we'd watch football on the analog channel and record on the HD-DVR and all was well. When I got the Samsung, I did an auto-scan and was pleased to discover that it 'found' several HD channels. Here are my issues/questions:
1) Some of the HD channels are perfectly clear and come in great - others are digitally garbled and impossible to watch...not as bad as trying to watch scrambled porn back in the days of the sliding cable channel selector, but bad enough... what gives?
2) I went to the link in this thread and typed in my zip code - looks like there are 103 digital channels in my market - cool... but almost none of the 'mapping' matches what my Samsung 'found' in the auto setup... what gives here?

Thanks in advance for your help.
Mike