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  #1  
Old 10-29-2004, 10:24 PM
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korben_dallas korben_dallas is offline
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Question Coax (composite) to S-Video

Do any vendors make some kind of converter/booster/amplifier/enhancer box that will take a coax (from analog cable) and break it down into s-video or component video? Obviously, the PC tuner card will do this internally (if it has a coax input), but I was thinking along the lines of some special hardware designed specifically to separate out the video (and audio) at the highest possible quality.
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Old 10-30-2004, 12:31 AM
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mightyt mightyt is offline
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Quote:
Originally Posted by korben_dallas
Do any vendors make some kind of converter/booster/amplifier/enhancer box that will take a coax (from analog cable) and break it down into s-video or component video? Obviously, the PC tuner card will do this internally (if it has a coax input), but I was thinking along the lines of some special hardware designed specifically to separate out the video (and audio) at the highest possible quality.
Might try Radio Shack ... I bought the "RCA to S-Video Signal Converter" and it worked great. I also bought the "4-Way Video RF Modulator" for my son and it worked great as well.

http://www.radioshack.com/images/Pro...OME15-1215.pdf

http://www.radioshack.com/product.as...5Fid=15%2D1215

http://www.radioshack.com/category.a...9%5F000&Page=1

Also I bought the "1-to-4 Bi-directional Cable TV Amplifier" when I added to many splits to my cable. This did the trick as well.

http://www.radioshack.com/category.a...1%5F000&Page=1

So for me ... RS has worked out OK so far ...

Good luck ... T.
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  #3  
Old 10-30-2004, 01:46 AM
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nielm nielm is offline
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Quote:
Originally Posted by korben_dallas
Do any vendors make some kind of converter/booster/amplifier/enhancer box that will take a coax (from analog cable) and break it down into s-video or component video? Obviously, the PC tuner card will do this internally (if it has a coax input), but I was thinking along the lines of some special hardware designed specifically to separate out the video (and audio) at the highest possible quality.
The quality has already been lost when the the coax composite video signal is generated -- you cannot get extra quality back by splitting the signal back up again... (an analogy -- listening to an AM radio station on a high end Hi-Fi )
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Old 11-24-2004, 03:04 AM
bluenote bluenote is offline
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Hi Nielm

Ever seen an RF booster in operation when you've got poor PQ to begin with?
Logically what you say is true, but in my experience the subjective end result can be improved.

FWIW

Cory
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  #5  
Old 11-24-2004, 03:18 AM
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but, coax composite video is not RF and coax->Svid converters are passive devices with no amplifiers
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  #6  
Old 11-24-2004, 02:03 PM
zoundz zoundz is offline
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Let's just clarify which apples and oranges we are talking about here.There are a number of different types of signal being discussed.
-----------------------------
Analog Cable, coax - the signal coming out of a coaxial cable with an F connector on it that comes from the cable company.

If it is analog cable, it is an RF signal containing modulated carriers on many channels from 2 to 125. It is necessary to have a cable ready TV tuner or tuner card to get anything from this signal. There is no other way. The output from the tuner or tuner card can be composite video (yellow rca or single BNC), S-video (separate luminance and chrominance on s-video connector) or component video (3 rca's or 3 BNC's) at 480i. The audio information is also contained in the modulated carrier and is available separately from the video.
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Digital Cable, coax - also comes out of a coaxial cable with an F connector. It can be on the same physical cable as the analog cable.

Digital cable is closely related to the OTA digital signals that you can receive from an antenna. It requires a STB from the cable company (it is conceivable to receive it using other receivers, but you need to know the exact details of what the cable company is sending). The STB can output a modulated analog signal on channed 3 or 4, composite video (yellow RCA), S-Video (s-video connector), or component video (3 RCA).
-------------------------------

Satellite Cable - also a coax cable with an F connector on the end.

The signal on this cable is downconverted by the LNB on the dish to an L-Band frequency between 950 and 2150 Mhz from the original satellite signal. A satellite receiver STB is necessary to get anything out of this cable. There may be encryption and the signal can be in any one of a number of formats, each of which requires a specific receiver. The output from the receiver, when tuned appropriately can be a modulated analog signal on channel 3 or 4, composite video, S-Video, or component video, depending on the receiver. The audio is available in any one of a number of ways, again depending on the receiver.
-----------------------------------
Composite Video

Composite video consists of a single video picture signal which is distributed on coax cable, usually with a yellow RCA connector or a BNC connector. The signal is a 1 volt P-P signal that contains both the luminance and the chrominance information for the picture. The color is modulated onto the luminance using 3.58 MHz carrier. This signal expects to be fed into an input that is terminated at 75 ohms. It can be distributed to multiple places by either daisy chaining (loop thru with a termination only at the end) or by using a distribution amplifier that will feed multiple terminations. This signal can be converted to S-Video using a passive device that is readily available at RS and other places. This device merely separates the modulated chroma information from the luminance. There may be some degradation of the PQ or not.
-----------------------------------

S-Video

S-Video is closely related to composite video. There is no additional signal information. S-Video is distributed on 2 coax cables (usually in one jacket) with an S-Video connector on the end. The luminance information is sent down one cable and the chrominance down the other. Both signals expect to be terminated at 75 ohms. The distribution rules are the same as composite video only you need 2 distribution amplifiers (usually one box) to replicate the signal. The same passive device that separates composite video into S-Video can be used to combine S-Video into composite. Just turn it around (not kidding).
-------------------------------------

Component video

Component video consists of either 3 or 5 separate signals. Three of them are the picture information and can be either RGB (equal red, green, and blue signals), YUV, YCrCb, YPbPr (a luminance signal (Y) and 2 color difference signals (one red, one blue - the details aren't necessary)). Most component video is distributed on just these 3 signals, in which case the sync information is superimposed on the Y signal or the G signal (sync on green). In the case of computer monitors (VGA connector) the signal is usually RGBHV, in which case H and V are the horizontal and vertical sync signals. Component video can not easily be converted into either composite video or S-Video. Significant electronics are involved in encoding component into composite. Likewise, a decoder is required to convert composite or S-Video into component.
-----------------------------

All composite and S-Video that are readily available will be 480i. No progressive, no HD.

Component video can be any of 480i, 480p. 720p, 1080i, or 1080p depending on whether it is SD or HD, interlaced or progressive. Different monitors can deal with whatever different formats they are designed for. Most HD monitors, but not all, can handle all but 1080p. Some can handle that as well.



Hopefully this clarifies some of this information.
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  #7  
Old 11-24-2004, 02:38 PM
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Cnovak,

Do you have an RF booster?

Right now I'm just using a passive splitter I got from the cable guy. It seems to work fine, but I was wondering if they made something that could boost the signal and potentially clean it up a bit.
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  #8  
Old 11-24-2004, 04:21 PM
bluenote bluenote is offline
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Hi korben

Yes I do have an RF booster, and I've found that they do work. I don't think they will solve every problem you can have, but they do what they are designed to do and is definitely worth a try if you notice degradation after splitting, or if you have poor signal in the first place. I note that I don't actually have mine hooked up to my PVR at the moment but they are pretty cheap and I doubt it would hurt.

You don't happen to be doing digital cable STB to PVR are you korben? Im trying to figure out how to cable mine so that the STB is not dedicated feeding the PVR. (ie: only use the STB for digital channels or premium content). If you are I'd appreciate hearing about your setup.

Zoundz, thank you for that great explanation. I've read some descriptions of the various input/outputs, but that was a really great summary and made things much clearer for me. thanks

Cory
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  #9  
Old 11-24-2004, 04:58 PM
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I do have digital cable, but not in my room where my pc/pvr is. Actually, as well as Sage has been working with my analog cable, I am starting to prefer it over the room with the digital cable STB.

I looked into using Sage with the digital cable STB, but it appears the whole IR transmitter setup and channel delay issue is a bit too much for the lazy act of watching tv

The biggest problem with the digital cable STB is that no matter what output type you are using, you only get one channel at a time. So SAGE would need the ability to change the channel on your STB in order to actually watch live TV or schedule recordings. This is no different than using a VCR on an STB.

I'm actually considering dumping the STB's that I have and using Sage + analog cable in every room, assuming I can come up with the PC hardware :O
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