HD cable question

[1tribeca]

I realize that the only way to receive true HD thru your TV is to have it connected either thru HDMI or component...coax will not deliver HD into your panel. I spent the afternoon running cable across my house from basement up three floors behind walls to the kitchen ( I have a reallly good electrician who's awesome at pulling cable!!)

Anyway, my question is...

Isn't the cable coming into your box from outside coaxial? How come HD comes that far, but won't get transmitted thru coax right to your TV? Perhaps I'm WAY off here...any help?

 

[Hi Ho]

You can get HD through the coaxial cable if you use the digital tuner in your TV. The tuner will decode the signals and give you an HD picture.

The the case of a set top cable box, the box is decoding the signal. Once it's decoded it must go through component video or HDMI in order to get an HD picture. The RF output on the box is modulated to channel 3 at standard definition so you can connect it to a VCR or old TV.

 

[MDS]

What Hi Ho said, but note that coax is a type of cable. Composite video, s-video, component video, analog audio, digital audio, etc cables are all coax as is the cable from the cable company.

To be more specific the signal from the cable company is RF and is carried over the coax cable with an F-pin connector. That can be hooked up directly to the TV if it has a tuner but you should also be able to go from the wall to the cable box and from the cable box RF out to the TV.

What cannot carry an HD signal is composite or s-video cables from the cable box.

 

[Hi Ho]

That can be hooked up directly to the TV if it has a tuner but you should also be able to go from the wall to the cable box and from the cable box RF out to the TV.

You can do that but you won't get HD. The cable box modulates the signal to channel 3 just like a VCR and it's anything but an HD picture.

I used quad shield RG-6 for all of the RCA connector cables in my system. It's cheap and as good if not better than virtually all of the premade component or composite cables plus they are totally custom length.

 

[OttoMatic]

Anyway, my question is...

Isn't the cable coming into your box from outside coaxial? How come HD comes that far, but won't get transmitted thru coax right to your TV? Perhaps I'm WAY off here...any help?

The difference is in the modulation scheme.

Although the cables themselves are very similar (with the exception of the HDMI), the actual electrical signals on those lines are different.

The HD signal that's coming from the cable company or satellite has modulated, using lots of digital tricks and compression, all the channels that you are able to watch on your system. So you're thinking -- if they can get all those channels down this RG-59 coax or RG-6 (or whatever it is), why can't we send that same signal throughout the house using the existing wiring that we already have in place?!?!?

In theory, you could. However, the problem is that the TV itself if designed to demodulate an analog TV signal -- old school style. It just doesn't know how to demodulate that HDMI signal. Now, a new TV with and HD tuner built in can demod an HD signal, but it's looking for whatever's coming over the air. You would have to have some means to remodulate the signal from the cable box and send it down the RG-59 cable in your house to the TV that you are intending to watch.

My Dish box does something similar, but not in HD. Although the Dish 622 ViP HD receiver is indeed an HD box, it only does HD to the TV that's directly connected to it (via component or HDMI cable). However, in order to offer flexibility to the consumer (me) they allow you to be able to watch other TVs at the same time, with programming different than what another person might be watching on the HD set. It demods a channel and then remodulates it to a regular old analog TV channel, and then filters it and sends it back down the RG-59 that's in my house (no extra, special or different cabling is necessary). Through the Dish box, I can dictate what channel it will appear on when using the other TVs (in my case, there's one in the bedroom and one in the basement, and they will both show the same programming at the same time, since they are tied to the same output on the Dish box).

Anyway, that's what you want to do, but in HD. I, too, may be looking for a similar solution. What needs to happen is a remodulation of the HD signal (in my case, I would use the component outputs of my HD box, as I'm using the HDMI to go to my "big" TV). Remodulate the HD signal and send it down the coax (we may need to use independent cabling here, may not be able to use the existing stuff due to bandwith or spectrum conflicts). At the other end of the coax (at the "other" TV), we will need to demodulate that signal back into an HD signal (most likely component). Plug that into the TV, and you're done. The reason to do this, of course, is to be able to watch HD in the bedroom or the basement. I currently don't care much about doing this, but as flat screen prices continue to drop, I continue to think about it.

Anyway, hope that helps.

 

[jcPanny]

Antenna Input

FYI,
An Over the Air Antenna uses a single coax connections and can pick up the local stations in HD. I good broadcast that uses HD cameras and equipment like the world series has a better picture on my set than other source including upscalled DVDs.

 

[1tribeca]

Now I'm completely screwed up!!! However, the info you folks gave is awesome. So, if I'm running another TV in my kitchen, can I somehow send the HD signal to that set thru the coax? I think that was part of what was described no? if so, what do I need to purchase for hook-up?

 

[OttoMatic]

Nope, you won't generally be able to do that. You'd need a modulator at the cable box, and a demodulator at the TV. You'd also have to properly filter the signals. I'm sure it's technically possible, but I'm not sure that those devices exist. Maybe poke around on Google and see if you can find an HD modulator and demodulator.

So, yeah, it's possible if the hardware exists, but you won't be able to do it with a normal cable box and a normal TV.

 

[mtrycrafts]

Now I'm completely screwed up!!! However, the info you folks gave is awesome. So, if I'm running another TV in my kitchen, can I somehow send the HD signal to that set thru the coax? I think that was part of what was described no? if so, what do I need to purchase for hook-up?

That depends on the TV and how you wired the house from the point of entry of the cable TV and, if you have a cable box, where that is connected.
If your TV has built in tuners, NTSC and one for the HD channels, then you could send a coax to it but that needs to come from the entry point through a splitter, before the cable box. Then, your kitchen TV will do all the channel tuning independent of the cable box.

 

[stealth1]

Totally lost

Wow... sounds good but I lost this link the minute you got too techie. ha! So.... here is my problem. I want to put a small tv in my new kitchen. I have a cable outlet right beside the tv that works but the picture doesn't fill up the screen as i presume it is not a hd signal. I have 2 pvr's in the house and one normal cable box. I was hoping not to have to get an hd box as I don't have anywhere to put it in the new kitchen. I presume this box must be placed in a location where I can see it to switch the channels. That unfortunately is impossible. I don't want all the movie channels and stuff I just want to sit down and watch decent picture while i eat breakfast. Any easy suggestions? thanks... i love this site!! Paul

 

[markw]

you're gonna have to get aq bit tecchie to solve your problem. Simply put...

Wow... sounds good but I lost this link the minute you got too techie. ha! So.... here is my problem. I want to put a small tv in my new kitchen. I have a cable outlet right beside the tv that works but the picture doesn't fill up the screen as i presume it is not a hd signal. I have 2 pvr's in the house and one normal cable box. I was hoping not to have to get an hd box as I don't have anywhere to put it in the new kitchen. I presume this box must be placed in a location where I can see it to switch the channels. That unfortunately is impossible. I don't want all the movie channels and stuff I just want to sit down and watch decent picture while i eat breakfast. Any easy suggestions? thanks... i love this site!! Paul

Hi Ho gave you the answer in a nutshell in post 2 of this thread.

Unless that "cable outlet" passes unencrypted HD signal AND the TV in question has a built-in HD television receiver, you're gonna need a cable box and feed it's output to your TV's component (red,green,blue) inputs. ...and the corresponding audio inputs.

Somehow, I think all the advice offered here simply went unheeded. You may want to re-read the thread until it makes more sense. Not everything posted here is that technical. You should be able to garner the gist of it if you try.

 

[BMXTRIX]

It can be really confusing, but the bottom line is the same.

If you want all your channels and you want HD, then you need a cable box and then a component video or HDMI connection to your TV.

If you want to use the tuner built into the TV, then you will ONLY get the channels which are not encrypted. These are sometimes called 'free and clear' or 'clear QAM' channels because you can use a normal digital tuner (built into your TV) to tune those digital channels.

What you can't do: Output HD over a single coaxial cable from the cable box.

Why?

Because the signal going into the cable box is a mix of compressed signals.

The signal coming OUT of the box on the same type of cable, is no longer compressed, but is a full video signal modulated onto a channel your TV can see. Typically, channel 3.

Channel 3 is not a HD channel.

There ARE HD video modulators available.

Real time, HD video encoding for modulation?

About $5,000 to do it this way. At least, that's how it's done in the broadcast environment.

You can do wireless HDMI using extenders from Gefen or you can extend it over CAT-5/6 if you need to.

In fact, that's my gold standard now. Pull a couple of pieces of coax and pull at LEAST 3 pieces of cat-6 to any potential TV location. It gives you your home network, and allows for a HDMI source to be remote located as necessary.

If your ONLY connection point is a single pieces of COAX, then the answer is a cable box, or to plug the coax directly into your TV. Your limitations will be that the TV can't tune any digital channels which aren't a Clear QAM broadcast - which is a lot of them.

Obviously, there is the option of using the coax out of your cable tuner and putting your TV on channel 3. You've already seen the issue with this. You don't get HD, not even close. In fact, modulated channels are typically the worst possible way to connect a TV for image quality. So, not even as good as a standard composite video feed.