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Maniaxx

Long-range S-Video (Y/C) connection?

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Hi,

is it possible to get a stable long-range s-video connection (50-80m)? I have a s-video camera and if possible i would use that output instead of composite/BNC.

 

There are up to 20m retail cables (75ohm) available (for home cinema) but its not recommended to use cables longer than 10m (by wikipedia-de). They say luma and chroma will interfere and negative impact on signal runtime will occur or sth...

 

Whatsoever... is there maybe a trick to achieve larger distances? Twisted-pair or something?

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Yes you can use baluns but I don't know if it's worth the $. Composite to SVHS doesn't make much difference in cameras, SVHS has in the past carried 800x600 @60hz without issue. Unless the camera really has the added capacity I doubt it's really worth it. Especilly since the good ones all have stereo audio as well which just jacks the price up more.

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Y/C has slightly higher bandwidth for luminance and removes the typical 'dot crawl' effect of composite signal. The camera has OSD. The difference should be visible there. Maybe even only there... I can post some screenshots once the camera arrives.

 

I just know little about baluns. Full name is Balancer/Unbalancer and there are active and passive ones.

 

My current understanding of baluns is... one signal (line) will be adapted to twisted-pair (2 lines) via balancer and adapted back at the end with the unbalancer. Is this correct?

 

What is the approx. price for such baluns? And which ones do i exactly need? I found so many different ones, labeled 1:1 or 1:9 for examples. Not sure if this are even the right ones...

 

RG59 cable correct?

 

Y/C has 4pins... luma, chroma and 2*gnd. Do i have to "pair" all lines with baluns so i need 8 cables and 8 baluns?

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The way I have extended a 'S' video cable is NOT to use a 'S' video cable.

 

I will 'cut' a 6' S cable, separate the two inner cables, solder a RCA fitting on each cable (four in all, two for each end) and use RG-59 with the matting connector to extend the run. The pair of cables (one for 'Y' and the other for 'C') has to be the same cable (off the same spool) and the same length.

 

As much as I liked and used the S-VHS format, JVCs' choice for the connector and what I find within that 'S' cable just plan sucks. It's usually only 26 guage which is very fragile and tough to work with since it will break very easily.

 

Where the very small inner coxial cable meets the connector (RCA or BNC) you need to be careful of stress., I put a couple of layers of 'Scotch 33' electrical tape (the only stuff I use) and then use heat shrink tubing to seal theat end.

 

There are break out cables available if you can find them and don't mind paying the difference.

 

Maniaxx is right on with his description of S video. Actually Y/C is the correct term. When S-VHS came out 18 or so years ago, I ran some tests between the same feed from composiet and then the S-video. As far as bandwidth, it was only measurable on a scope with a multiburts pattern, but the dot crawl was vey noticeable on the TV.

 

BUT, that only depended on how good or bad the comb filter was in the set. better filters reduced the difference (composite looked better) which meant there was less of a improvement over composite when the Y/C path was used.

 

I'm sure if you compared a 3 chip CCTV cameras composite vs Y/C out (if there is a camera that has both) the difference would be greater.

 

AFAIK, JVC shot themselves in the arm with all their talk about S-video and having a TV with that input. I feel most thought, if you didn't have that type of set, you wouldn't gain anything. Hence, why S-VHS didn't sell as it should of. It was their 'Sony' mistake of the 90's.

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I tried cat5 (awg26) but somehow the picture is heavily skewed and too dark. You can't notice anything but differences in brightness if you point the camera to dark or bright places. Cablelenght is about 5m (16ft.).

 

I had to assemble the cable myself since it is a custom 8pin > 4pin mini-din connection. Does it need some extras termination or something?

 

Anything wrong with awg26?

 

Edit:

Ok.. forget it. Luma and chroma was swapped due to horrible article at wikipedia. Talk about male jacks and show female schematics.

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