HDTV Forum

So, if I understand this correctly, my TV has a tuner in it that will decode HD provided via coax. A cable box also has a tuner in it that will decode HD but relays that signal to the TV via component or HDMI cables only...all other outputs on the cable box are SD...

So, technically, coax can "handle" HD signals...it just isn't wired that way??? I would assume this is due to signal loss from combining all information on one wire???

There is RF DTV which can carry HD content. That is no different than RF NTSC, what you have watched your whole life, but NTSC is SD only. Either one requires a different tuner to receive and decode the signal into...

RGBHV, Component video or digital video via HDMI/DVI for HD or composite video for SD.

If the tuner is built into your TV you won't know that but that is what had to happen for you to watch it.

External HD sources output component video or digital video.

Cable and Satellite HD receivers retain RF and video SD connections for SD users. If you have an HD display then you must use the component video or digital video outputs to get HD.

While it is certainly possible to output HD as an RF signal and have your tuner receive and decode that just like your old TV that would cost more money and is of questionable benefit.

Let me try the novice explanation. Sorry, Richard, but yours gave me a headache!

Coax carries a RF signal. That RF signal contains one or more UHF or VHF channel. Each UHF or VHF channel can be NTSC (analog cable or antenna) or ATSC (OTA Digital TV). Only ATSC supports HD resolutions. NTSC is always SD.

If your TV has a HD tuner then it can accept the ATSC signals and decode them into HDTV channels. Otherwise the coax input only decodes NTSC (SD).

What the cable box is doing is broadcasting a NTSC channel (usually on channel 3 or 4) over the coax. This was done back when TVs only had a coax input (cable ready) and not A/V type inputs. It's not the cable - it's what is being put on the cable that determines whether it's HD or SD. And in the case of a VCR or cable box or even a DVD player or DVR, using the coax restricts you to NTSC which means SD only. And it's usually the worst quality SD at that.

I might be oversimplifying it but I think that's how it works.

Dave,

I read your chain from Dec/Jan on picture quaity. I have a similar issue. I have a new 5053 Samsung Plasma and had HD service installed yesterday by Charter. I have a Motorola box with the 5 cables and NO HDMI conections. The cable technician even thought the HD channels did not look good. He said the signal strenght was right in the middle but I could get a booster to get better picture. Do I need that or is there another recommendation you might have?

Thanks!

rwadejr wrote:Dave,

I read your chain from Dec/Jan on picture quaity. I have a similar issue. I have a new 5053 Samsung Plasma and had HD service installed yesterday by Charter. I have a Motorola box with the 5 cables and NO HDMI conections. The cable technician even thought the HD channels did not look good. He said the signal strenght was right in the middle but I could get a booster to get better picture. Do I need that or is there another recommendation you might have?

Thanks!

If you have enough signal to get a digital picture without pixellation or dropouts then increasing the signal won't help it. Make sure the Charter box is outputting HD resolution and matches the TV's native resolution as closely as possible. Then use DVE or Avia to set your user controls correctly.

Thanks for the reply. How do i check the Charter box's output and what is DVE/Avia? Thanks!

Hi-

At the risk of "upsetting" some of our other readers, I have experienced the solution to our problems by getting the ONLY cable box from COX which does have a "HDMI cable" to the TV set, rather than those "composites" - it had to be the recorder version, at $10 month extra but that solved the issues!!!

You might try to exchange your new cable box/remote
for their HD Recorder Box / Remote.

Why would your statement upset readers? Because you found HDMI superior to component? There are plenty of reason for that revolving around proper circuit design for those connections.

Hi -
We solved some wierd "HD Issues" by exchanging the initial HD Cable Box/Remote for the ONLY one our
company had that used "HDMI" from it to the HDTV.
(A Recorder)---Costs $10/Mo. more but FIXED our issues, for live or recorded shows!!! Since your TV has (2) HDMI ports, worth a try !!! We were told that this was ONLY way for All Digital "2-Way" hook-up between TV & HD Cable Box.

"DAVE" would know for sure !!!!

eliwhitney