HD Question- cable box vs. direct

[Neel]

My parents bought a new Sony 50" Bravia LCD TV. Charter Cable made us get a box in order to receive the HD/digital local channels (Scientific Atlanta Explorer 8300 HD). However, if I connect the coaxial cable directly to the TV, I can pick up the local HD/digital channels as well. The TV maps them into strange numbers like 87.5, 101.9, 107.3, etc... However, I don't know if it's me or what, but the digital channels seem to have more blur when I connect the cable directly to the TV versus using a cable box. It doesn't seem like it should matter either way, but I could swear the digital/HD channels seem a bit clearer with the box. Does anyone know if the box does anything to process the picture better or has anyone experienced the same thing? It's driving me crazy so I thought would ask you guys since I expect the cable company to tell me to rent their box. Thanks.

 

[w9wi]

My parents bought a new Sony 50" Bravia LCD TV. Charter Cable made us get a box in order to receive the HD/digital local channels (Scientific Atlanta Explorer 8300 HD). However, if I connect the coaxial cable directly to the TV, I can pick up the local HD/digital channels as well. The TV maps them into strange numbers like 87.5, 101.9, 107.3, etc... However, I don't know if it's me or what, but the digital channels seem to have more blur when I connect the cable directly to the TV versus using a cable box. It doesn't seem like it should matter either way, but I could swear the digital/HD channels seem a bit clearer with the box. Does anyone know if the box does anything to process the picture better or has anyone experienced the same thing? It's driving me crazy so I thought would ask you guys since I expect the cable company to tell me to rent their box. Thanks.

I'm guessing what you found with the TV connected directly to the cable are the SD digital channels.

At least here in Nashville, digital cable carries both the SD and HD versions, on different channel numbers. So WSMV appears twice, once in SD and the other place in HD.

I'd suggest you keep looking, you're likely to find each local station again on a different channel & likely, that channel will indeed be HD.

I can't think of a reason (except for really poor design!) for the cable box to deliver a sharper picture than the TV itself.

 

[Neel]

No. There are the digital versions. The SD channels still appear on channels 2,4,5,7,9 and 11. The digital versions are on channels 101.9, 107.3, etc... and when a program is in high-def, the bars on the sides go away so I know for sure it is the digital channel. I just felt there was a difference in resolution with and without the box and I don't know if it has to do with connecting the coaxial directly to the TV or going through the box and using component or HDMI cables.

 

[BRNout]

Can you get 1080p resolution directly through the coax feed? I thought that you need component cable or HDMI to do that. So, yes can be getting HD - but I don't know that you're getting as sharp of a picture as you could be.

Then again, I'd love to be educated on this.

 

[imhomerjay]

I belive your TV has a QAM tuner. I'm not an engineer so I know I will get corrcted by those smarter than me, but when I discovered the same thing with a TV of my own, I dug around to find out what was up.

The cable companies assign channels to various QAMs in their system--the numbering system doesn't follow any logical conventions to an outsider--they just have slots in the 'pipe' that carry the channels, and the cable boxes would know when you enter the channel number for your ABC HD signal to go to slot 87.10 (or whatever the number is). The local broadcast channels--even the HD ones--aren't scrambled, so your TV can pick them up by searching all of the slots.

 

[byron]

imhomerjay is probably right on this one. You can take your ZIP code and plug it into this website, and in most cases, get the ATSC off-air and digital cable placements for your general area (some including screen captures when available). The lineup numbers can vary, but in my case, what I saw on my QAM tuner matched the website almost channel for channel.

http://www.silicondust.com/hdhomerun/lineupui?Cmd=LocationProgramsWeb&Country=US&Postcode=32771

In most areas, especially Central Florida's service area (Bright House territory) the cable company will proudly claim it officially provides "no support" for Clear QAM, so what you see is what you get, and it may change week to week depending on moves made by the operator, without warrant or notice. Generally you'll see all the locals, in either HD, SD or both... and some PPV barker channels, government channels, or maybe one or two standard cable offerings depending on what your operator coincidentally has placed in the same tuning range. (Some areas have reported TNT HD in the clear!)

Byron

 

[Neel]

yes, the TV manual does say it has a QAM tuner. And yes....right now I can even get 2 HBO's and Cinemax for free when I connect the coax directly. I still can't figure out if there is a difference in resolution between direct connection from the coax and thru the box via HDMI.

 

[byron]

See... that just irks me. Why can't Bright House let that HBO and Cinemax slip through?

I'd imagine your HDMI from the box would be better, because the box is receiving more the programming digitally vs. what the Clear QAM is only capable of picking up on these few open channels. Better in terms of overall digital quality however, and not necessarily better on picture quality. The box is pretty much decoding in the same manner as the Clear QAM tuner is, if I'm not mistaken, but obviously the settop box is going to be able to decipher more of the programming coming to you from the cable plant vs. that Clear QAM tuner. Just my opinion.

Byron

 

[KML0224]

It shouldn't be any different. Here in New Britain, CT (near Hartford), Comcast carries WFSB-DT (CBS) channel "3-1" on cable channel 233. My Sanyo 26" LCD HDTV (Model DP26746) has a QAM tuner. It gets WFSB-DT "3-1" on channel 89-1. The picture with my friend's cable converter (hooked with a progressive cable) and on my TV (with the coaxial cable connected to the "Digital Antenna In" 75 ohm input) were identical. Anyways, here's what my QAM tuner gets right now:

82-1 = WTXX-DT 20-1 Waterbury (CW)
82-2 = WEDH-DT 24-1 Hartford (PBS) [PBS-HD at night]CABLE ONLY
88-1 = WVIT-DT 30-1 New Britain (NBC)
88-2 = WTNH-DT 8-1 New Haven (ABC)
88-3 = WVIT-DT 30-2 New Britain (NBC Weather Plus)
89-1 = WFSB-DT 3-1 Hartford (CBS)
89-2 = WTIC-DT 61-1 Hartford (FOX)
89-3 = WFSB-DT 3-3 Hartford (Eyewitness News Now)

 

[kenglish]

Many Cable systems are gearing up for "ADS (All-Digital Simulcast)", so they will carry an analog NTSC signal, a digital SDTV signal, and (if available) a digital HDTV signal, from each local station.

Like was mentioned above, you might be seeing the digital SD signal. Here in SLC, the HD channels are sent out on the 100+ channels, and some clear-QAM tuners won't find them on a normal scan. You have to manually enter the channel number, one at a time, to let it "explore" that RF channel for the content....then, it "learns" what is there and stores it.

Cable moves the digitals around a lot, not to frustrate you, but to optimize the bandwidth. It's possible for stations to send a "Cable Virtual Channel Table" with their fiber-optic feed to the Cable Headend, allowing the clear-QAM sets to associate the physical and virtual channel numbers, so they "make sense".

 

[w9wi]

No. There are the digital versions. The SD channels still appear on channels 2,4,5,7,9 and 11. The digital versions are on channels 101.9, 107.3, etc... and when a program is in high-def, the bars on the sides go away so I know for sure it is the digital channel. I just felt there was a difference in resolution with and without the box and I don't know if it has to do with connecting the coaxial directly to the TV or going through the box and using component or HDMI cables.

What I was getting at is that there are probably two digital versions.

What you're seeing on channel 2/4/5/etc. are the analog SD versions, still being carried by the cable for the benefit of subscribers who don't have digital cable.

Systems also carry a digital version of the analog SD signal, for subscribers who have digital cable but not HD. Presumably this is the station's analog signal, received at the cable company and converted to digital there.

Finally, there's the digital HD channel, delivered to subscribers who have both digital and HD.
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However, your comment about the side bars going away when a program is HD would seem to contradict that idea. So, on a specific channel, the side bars are there sometimes but go away during HD programs?

Can you receive any HD stations OTA at that location? Try connecting an antenna, switching from cable mode to air mode, and rescanning. If you're close enough to the towers, a few inches of wire might do. (within 2-4 miles of the towers, you might be able to leave the cable connected!)

If you can get any HD stations OTA, do they come in as sharply as the HD signals through the cable box?

It is possible the TV has a HD display but the built-in tuner only delivers SD. It seems VERY unlikely - there is little if any difference in cost between a SD digital tuner and a HD unit - but it is technically possible.

(it is even remotely possible that the tuner can receive HD OTA but not via cable. But I find it *impossible* to believe anyone would make a TV that would do that.)

 

[Neel]

Unfortunately, you can not get any OTA digital channels with an antenna. That is what I tried for initially, but was unsucessful. I think it is digital/HD that i'm receiving through the cable. I wish I could do a side by side comparison. I've noticed that when a program is in HD, it is almost always sharp, but it is in digital where lot of times I see blurriness and I think having the cable box makes a slight difference. Oh well.

 

[ShawnHill1]

I've mentioned this before, but I have the same type of setup as many of you. I have both Time Warner Cable (the primary cable operator in my area) and DirecTV in our home, and the SD versions of the local stations on TWC show up much better than on those on DirecTV. I have one of the signal ampfilier boosters from RadioShack, and it helps the reception a great deal, especially on the analog side.

Here's the list of channels I receive (digital) through the QAM tuner for free...

31-1 QVC Network (also on 87-4)
31-2 Los Angeles CityView 35 (city government channel)
31-3 LA36 (community access channel)
62-1 Video on Demand Barker channel
62-2 KTLA HD (The CW)
79-1 KABC SD
79-2 KAZA SD (Azteca America)
79-3 KCET SD (PBS)
79-4 KCOP SD (My Network)
79-5 KDOC SD
79-6 KTTV SD (Fox)
79-7 KMEX SD (Univision)
79-8 KWHY SD
79-9 KTLA SD (The CW)
79-10 KJLA SD
79-11 KFTR SD (Telefutura)
79-12 KXLA SD
80-1 KBEH SD (MTV Tres)
80-2 KCBS SD
80-3 KCAL SD
80-4 KNBC SD
80-5 KPXN SD (Ion)
80-6 KTBN SD
80-7 KLCS SD (PBS)
80-8 KSCI SD
80-9 KVEA SD (Telemundo)
80-10 C-SPAN
80-11 Home Shopping Network
81-1 to 81-11, 82-1 to 82-11, 106-1 to 106-3, 107-1 to 107-3 Video On Demand (movies and specials spontaneously from various networks)
86-8 Time Warner Cable barker channel
87-5 Superstation WGN
87-6 KOCE SD (PBS)
91-1 Pay Per View Barker channel
92-11 V-Me (KCET Digital)
93-1 KCBS HD
93-2 KNBC HD
93-3 KNBC News Raw (KNBC-DT4)
94-1 KABC HD
94-2 KTTV HD
94-3 KCET HD
96-2 KOCE HD (programming differs from main KOCE signal)
99-1 Los Angeles Public Access
99-2 Eudcation Access (no educational programming at all; just informericals)
99-3 Local Origination Channel
99-4 TV Guide Network (Los Angeles listings)
99-5 TV Guide Network (Inglewood listings)
99-6 Inglewood Public Access
99-7 The Weather Channel
100-1 Fox Sports Net HD
104-3 KCAL HD
105-9 to 105-56 Music Choice (I won't list all 48 channels here)
108-2 NHL Centre Ice stats channel
110-11 NBA League Pass barker channel
116-1 C-SPAN 2
116-2 C-SPAN 3
116-3 NBC Weather Plus (KNBC-DT2)
116-4 ABC 7 Plus (KABC-DT2)
116-5 ABC 7 Weather Now (KABC-DT3)

 

[anotherguyTN]

I tried to enter different zip codes for the Jackson and Dyersburg, TN areas at the Silicon Dust Website, but it only showed listings for Memphis. Does this only work for larger cities?

 

[FloydB]

Unfortunately, you can not get any OTA digital channels with an antenna. That is what I tried for initially, but was unsucessful. I think it is digital/HD that i'm receiving through the cable. I wish I could do a side by side comparison. I've noticed that when a program is in HD, it is almost always sharp, but it is in digital where lot of times I see blurriness and I think having the cable box makes a slight difference. Oh well.

Ah, I have your answer! The SD 4x3 programs are being upconverted on the HD signal, therefore look like crap. I worked for a station that obviously had the monitors for the SD and HD signals. And, every time we played a syndicated SD show, the HD looked like crap. More than likely your format is 1080i instead of 720p (which is what this station is) so your SD stuff is going to look like crap. I'm pretty sure the box filters some of the signal to clear it up with the HDMI connection. If you went straight coax from the box (if it's possible), then you'll probably see almost the same thing.

 

[byron]

I tried to enter different zip codes for the Jackson and Dyersburg, TN areas at the Silicon Dust Website, but it only showed listings for Memphis. Does this only work for larger cities?

I'm thinking the answer is yes. I've entered some for my area, and it's either off by a few or totally wrong for OTA signals you could expect to see in the market by distance/location of the ZIP code tried.

Byron