Coaxial for best quality?

[Caple]

Hello everyone.
I read once, can't remember where, that if I'm not using anything like a STB or a VCR to tune the channels I can connect the coaxial cable straight to my capture card and I'll have the best quality possible.
S-video would be better and make a good difference only if I'm tunning channels on other devices.
Is it true?
My VCR was sent to repair and I can only connect the coaxial straight to my Hauppauge card. I have to say I didn't notice any big difference on the image quality (before = svideo, now = straight coaxial). Maybe because my source is not really good. Who knows.
Does anyone agree with that statement?

[sanlyn]

Are we to assume you mean you're using your captue card as a tuner, instead of plugging your coax into another device, using that device as a tuner, and then feeding from tuner to capture card with s-video, composite, etc.?

Look at it this way. Regardless of how you're tuning or how you transmit what you've tuned, the coax is the source. The cable source will display whatever noise it brings to the table, and coax wire itself is a noise generator, not to mention all the transmission amplifiers, bridging and splitting circuits, etc., etc., along the way, before the cable signal gets to your location.

Between that source and your capture card, every added piece of wire and electronic gear will change that incoming coax signal, to some degree, before it reaches your PC. Even if you tune with components that have noise filters, etc. (most better VCR's and well-built tuner boxes have these filters), every added component, piece of wire, and connecting plug will cause some change in that source. The more connections, the more chance for either majhor clean-up or more gunk in the image.

So, figure that whatever you use for a tuner, it's working with the source the cable people feed into whatever you're using. The more you process it (considering you're using the standard gear that everyone else uses, not $750,000 worth of recovery equipment), the more the original source will be changed, for better or worse.

The more you do to your source before you use it, the more it will be altered by the time it gets where it's going. Anything you place in the path of that source can do harm or good. More than likely, the first thing the cable encounters as it enters your premise is a splitter, or an amplified splitter. Unless you're using some really pricey splitter device with all sorts of sophisticated compensation circuitry, your splitter has already made a major change to your source. If it's like the average splitter, it's added low-frequency grain and chopped off some high-frequency detail, not to mention cutting the signal strength in half. The average splitter also introduces a layer of video noise in the form of FM or RF temporal streaking and flickering. I used a splitter a few years back that even changed the color balance (sucked too much blue out of it). So you can imagine what tuners, inpiut-output circuits, more wire and plugs, etc., can do to your original source.

I note when I record directly to my ATi card that the picture is sharper, but more grainy, and seems to have high contrast. But after it comes out of my digital cable box, the image has lost some visible detail and doesn't seem as solid or snappy. Not bad, really, but it sure as heck is obvious that something has happened between the source arriving in my home and it's stopping point in my DVD recoder's Line-In.

[Caple]

I asked that because I didn't see much difference between the two circumstances stated in my case.
I knew everything you wrote about what happens every step, I just wanted to know, in general, if people think using the card as a tuner, without any device between the cable and the card, is as good as using a external tunner (in my case).
When I purchased my LG DVD/VHS Recorder combo and started using svideo... man, it was like night and day. I realized my old VCR, using composite cables, gave me a terrible image, compared to my LG.
As I have never used the cable straight to the card tuner and had read all that I explained above, I wanted to know what people thought about it, in general way.
Thanx for replying.

[edDV]

...

As I have never used the cable straight to the card tuner and had read all that I explained above, I wanted to know what people thought about it, in general way.
Thanx for replying.

Analog tuners vary in quality. This used to be more true in the past where simple VCR's had simple tuners. Premium TV sets and S-VHS VCR's had better tuners with expensive analog comb filter NTSC or PAL decoders. Usually a premium TV had a much better tuner than a typcal cable box. You could get a superior picture for the analog channels by plugging the cable directly into the good TV.

In recent years cheap tuner "cans" have improved and NTSC decoders with comb filters are implemented in cheaper chips. The same types of parts are found in cable boxes, DVD recorders and capture cards. The cheapest TV sets, capture cards and VCRs still ship with crappy tuners. But DVD recorders, "HD" generation cable boxes, mid range capture cards and mid range TV sets have similar analog sections. You need to test them with your eyes to see which is best.

Just as they are all getting to be good to very good, analog broadcasting is due to be shut down in Feb 2009. Analog NTSC will continue on the lower cable channels for a while but get ready for the new digital ATSC tuners that will be required for any over the air reception.

[Caple]

Brazil choose the japanese digital TV system, ISDB-T, some months ago, to be the base of our digital system. With transmissions starting this year, about June or August, in São Paulo and Rio de Janeiro, and in 7 years for all the country. In 10 years the analog system will be shut down.
It will take a long time to get here on my city, so I still have a long time to read and learn more about it, and keep playing with analog as I wait for it.
As ISDB-T is based on DVB-T system, maybe DVB-T cards can receive and capture ISDB-T streams. At least I hope so. Need to research about it.

And edDV, let me ask you something. I see you have a Canopus ADVC 100. I tried to buy one last year, but reading some reviews and posts here seems like the ADS Pyro is almost the same, for half the price. Have you ever tried the ADS unit? If it's really as good as Canopus, I'm interested.
Thanx.

[edDV]

...

And edDV, let me ask you something. I see you have a Canopus ADVC 100. I tried to buy one last year, but reading some reviews and posts here seems like the ADS Pyro is almost the same, for half the price. Have you ever tried the ADS unit? If it's really as good as Canopus, I'm interested.
Thanx.

Ahh, I missed you were in Brazil. You have more time with analog tuners.

I haven't used the ADS Pyro yet. Others say they are similar in the basic modes. If your area uses PAL-M, you should look for specific feedback that PAL-M is supported by the Canopus or ADS units. I've used the Canopus ADVC for NTSC and Euro PAL but not yet PAL-M (3.58MHz subcarrier).

[Caple]

The TV system would not be an issue. My DVD recorder outputs NTSC (at least I had to change my WinTV2000 software from PAL-M to NTSC to work correctly).