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Hall Of Fame
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Discussion Starter · #1 ·
...that coax is the worst connection for hooking up a receiver/DVD/etc. to your tv, but yet the lines from the satellite are all coax? Wouldn't that be like running composite cable to your reciever and then running HDMI to your tv? Garbage in, garbage out.

Please school me.

(and yes, this probably should be in this sub forum, but it's the only one I check)
 

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thats an apples to oranges comparison. In a perfect scenario, RG6 (coax) can carry an analog tv signal as good as HDMI/S-Video/Composite/Component, it is also capable of carrying large amounts of data (hence why its used to carry the signal from the Satellite to the receiver, b/c at this points its just raw data, not video). when the receiver converts this data stream to actual video, its in a digital format... so mediums such as s-video/composite video (component/hdmi/dvi for HD) are recommended b/c you're carrying a 100% digital video feed, which couldn't be handled by a medium such as RG6 without converting it back to analog and in turn degrading the video quality.
 

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Discussion Starter · #3 ·
So it's going down the coax from the dish to the reciever digitally, but it can't go from the reciever to the tv through coax digitally? I'm still confused.
 

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mtnagel said:
...that coax is the worst connection for hooking up a receiver/DVD/etc. to your tv, but yet the lines from the satellite are all coax? Wouldn't that be like running composite cable to your reciever and then running HDMI to your tv? Garbage in, garbage out.

Please school me.

(and yes, this probably should be in this sub forum, but it's the only one I check)
You are confusing the function with the method of delivery. It is crazy to take an HDTV and connect to a source via Channel 3 modulated RF. Rotten resolution and picture quality. That has NOTHING to do with COAX, it is the signal going through it.

Look at component cables...what are they? COAX. Really great picture. So while these two scenarios have coax in common, the signals range from horrible/unusable to near perfect...so obviously the issue is not coax.

Now for a really silly question: just how do you propose we get the RF (radio frequency signals) from the dish to the HR20 without a transmission line. Short of another radio link, there isn't one. (Like wireless, for example).

So now it becomes our best choice of transmission lines. How to choose:

1. Loss
2. Environmental Factors
3. Availability
4. Cost

There aer two (practical) choices for RF transmission lines:

1. Balanced (twin lead/open wire line)
2. Coaxial cable

Balanced line:

a. Very hard to make balanced line the operates effectively at 2000 Mhz. (you can't make it small enough).

b. Balanced line, even it could be made effectively/practically for these frequencies has to be installed VERY carefully, no metal or conducting surfaces can come anywhere near (several inches) the line, or it loses balance and is less effective.

c. The loss in balanced line goes WAY, WAY up when the line has water on it. (or even dirt/grime), and it begins to both radiate and receive interference from outside sources.

c. Balanced line has much lower loss than coax (of practical sizes), but given items a, b, and c above it is NOT usable for a transmission line for these frequencies.

Coaxial Cable:

a. Impervious to jacket moisture issues.

b. Predictable (and unchanging) loss in a wide variety of environmental conditions.

c. Can be run over/through and upon conducting objects with NO EFFECT on it's loss or impedance characteristics.

d. It is readily available

e. It is relatively inexpensive

f. Doesn't radiate, rejects inteference.

There are other considerations, but this is a "snapshot" of the issue.

Obviously coax is the way to go.
 

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TV's are not designed to accept a digital signal via coax. (this may not be true on new units with cable cards slots). That's why the sat receiver converts to analog to ship via the coax output. Analog does not support the resolution that digital can.
 

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Discussion Starter · #6 ·
hasan said:
You are confusing the function with the method of delivery. It is crazy to take an HDTV and connect to a source via Channel 3 modulated RF. Rotten resolution and picture quality. That has NOTHING to do with COAX, it is the signal going through it.

Look at component cables...what are they? COAX. Really great picture. So while these two scenarios have coax in common, the signals range from horrible/unusable to near perfect...so obviously the issue is not coax.

Now for a really silly question: just how do you propose we get the RF (radio frequency signals) from the dish to the HR20 without a transmission line. Short of another radio link, there isn't one. (Like wireless, for example).

So now it becomes our best choice of transmission lines. How to choose:

1. Loss
2. Environmental Factors
3. Availability
4. Cost

There aer two (practical) choices for RF transmission lines:

1. Balanced (twin lead/open wire line)
2. Coaxial cable

Balanced line:

a. Very hard to make balanced line the operates effectively at 2000 Mhz. (you can't make it small enough).

b. Balanced line, even it could be made effectively/practically for these frequencies has to be installed VERY carefully, no metal or conducting surfaces can come anywhere near (several inches) the line, or it loses balance and is less effective.

c. The loss in balanced line goes WAY, WAY up when the line has water on it. (or even dirt/grime), and it begins to both radiate and receive interference from outside sources.

c. Balanced line has much lower loss than coax (of practical sizes), but given items a, b, and c above it is NOT usable for a transmission line for these frequencies.

Coaxial Cable:

a. Impervious to jacket moisture issues.

b. Predictable (and unchanging) loss in a wide variety of environmental conditions.

c. Can be run over/through and upon conducting objects with NO EFFECT on it's loss or impedance characteristics.

d. It is readily available

e. It is relatively inexpensive

f. Doesn't radiate, rejects inteference.

There are other considerations, but this is a "snapshot" of the issue.

Obviously coax is the way to go.
Thanks for all the info. I didn't realize that component cables were actually coax. So even though coax can transmit audio and video at the same time, these just separate the L/R audio and the three colors of video for a clearer picture?
 

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"TV's are not designed to accept a digital signal via coax"

What about over the air signals. I get a pretty good HD picture through coax cable.
 

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jbird said:
"TV's are not designed to accept a digital signal via coax"

What about over the air signals. I get a pretty good HD picture through coax cable.
You missed this part: "(this may not be true on new units with cable cards slots)."

Which is actually a little incomplete. What he should have said was "This is not true of new units with ATSC tuners designed to accept digital signals over coax."
 

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Which begs a different question: why didn't they just continue the well-established custom of modulating a signal to channel 3 or 4 (only this time, sending a HD signal via ATSC)? Sure seems simpler than the whole HDMI fiasco.
 

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walters said:
Which begs a different question: why didn't they just continue the well-established custom of modulating a signal to channel 3 or 4 (only this time, sending a HD signal via ATSC)? Sure seems simpler than the whole HDMI fiasco.
Well, for that matter, sticking with component, which though analog, results in a pristine picture all the way up to 1080p for many folks? I'll give you a one-word answer: paranoia. Content providers shoved HDMI (HDCP along with it) down hardware makers' throats for fear of pirated copies of HD content leaking out all over the 'net.
 

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mtnagel said:
Thanks for all the info. I didn't realize that component cables were actually coax. So even though coax can transmit audio and video at the same time, these just separate the L/R audio and the three colors of video for a clearer picture?
Without a bunch of complicated technical explanations, yes. The "coax" you keep referring to is just an RF modulated TV signal that has embedded in it both audio and video ...it is the poorest way to send a signal to an HDTV, to be sure.

Stop thinking about "coax", and start thinking about "video sources", or signals.

RF Modulated (what you call coax): lousy source, poor PQ, NOT Hi-Def

Component: (still a coaxial connection, just 3 of them) excellent source, very good PQ, Hi-Def

HDMI: (non-coaxial), DIGITAL, superb source, best potential PQ, Hi-Def

Composite: (coaxial) often called base-band video, better than RF modulated, not as good as S-Video, Component or HDMI. NOT Hi-Def

In order of video quality (lowest to highest) S-Video and below is not Hi-Def)

1. RF Modulated
2. Composite (base band)
3. S-Video
4. Component
5. HDMI

How audio is handled is a totally unrelated issue to video. My post is already too long to go into that part, but suffice it to say, you have embedded audio with Rf Modulated sources. All the others have distinct audio connections (either fibre optic digital, coaxial digital, or HDMI digital, or simple Left and Right, or even Monaural on some composite systems)
 

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walters said:
Which begs a different question: why didn't they just continue the well-established custom of modulating a signal to channel 3 or 4 (only this time, sending a HD signal via ATSC)? Sure seems simpler than the whole HDMI fiasco.
ATSC encoders are very expensive.
 

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Jeremy W said:
ATSC encoders are very expensive.
Not really, Dish use to sell one for their model 5000

http://www.coolstf.com/mpeg/HDTV/index.html#dn-atsc

The issue is copy protection, that is why they don't provide ATSC outputs.

This is how many people time shifted HD content for a long time, you could just slap in a ASTC tuner in a HTPC and make a copy of any movie and there was no DRM.

IMO ASTC output or HD-SDI would be the most consumer friendly interfaces. Under both you could use your old existing coax even rg/59 infrastructure for video distribution.
 

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btmoore said:
Not really, Dish use to sell one for their model 5000
And that article says it costed $300. Compared to the cost of including an NTSC modulator, which is pennies these days, the cost of an ATSC encoder by itself would be enough to make the receiver significantly more expensive. And there's really no reason to do it, considering the fact that an HDTV that doesn't have component and/or DVI/HDMI inputs doesn't exist. So why make the box more expensive?
 

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Jeremy W said:
And that article says it costed $300. Compared to the cost of including an NTSC modulator, which is pennies these days, the cost of an ATSC encoder by itself would be enough to make the receiver significantly more expensive. And there's really no reason to do it, considering the fact that an HDTV that doesn't have component and/or DVI/HDMI inputs doesn't exist. So why make the box more expensive?
It was a plug in option for the 5000. You could purchace a 5000 and use it with out this option.

That price was 7 or 8 years ago

The chip designs exist so to be produced in mass it would cost about the same as a NSTC and perhaps even cheaper as it is just a transport for a MPEG2 stream. You would have to convert MEPG4 to MPEG2 but that is a different issue and a lot easier than mpeg2 to mpeg4.

As I said, the big reason is copy protection, you can't copy protect an ASTC output, but it would be nice at least as an option.
 

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Jeremy W said:
Why? That's my biggest question that still hasn't been answered. What's the point?
Here is one, my entire house is wired for component video and digital audio distribution. This means I have 4 lines of coax going to 4 rooms and I have a matrix switch so I can switch multiple sources all so I can support a centralized distribution of HD video content. If there was a ATSC output, I could plug into a RF distribution amp and feed all 4 rooms with one coax line. I could even mix NTSC and ATSC on the same coax and run multiple ATSC and NTSC feeds on the same lines at the same time, all I would need is a tuner in each room and now ATSC tuners are cheap and typically standard on most displays.

In a simple scenario, if you had a HD tv in your bedroom and you had one in the living room and your house was wired for RF coax, you would only need 1 HD DVR or STB.
 

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Jeremy W said:
Why? That's my biggest question that still hasn't been answered. What's the point?
The difference is from the dish to your reciever the signal is compressed. Your reciever is uncompresses the signal then sends the raw uncompressed data over your component or hdmi cable.
 

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66stang351 said:
The difference is from the dish to your reciever the signal is compressed. Your reciever is uncompresses the signal then sends the raw uncompressed data over your component or hdmi cable.
I was talking about something totally different. Believe me, I don't need a lesson in Satellite TV 101. I know this stuff pretty well.
 
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