Maximum Cable Length

Published : 26th January 2004

Is there any recommended maximum cable length for a S-Video (Y/C) cable?

I want to run a 40m cable. Should I use an signal amplificator, or will it introduce more noise than just the long cable would pick up?

Thanks in advance,

Andre Moura
Tech. Support
Audio & Video
Ass. Torre de Vigia
SP - Brazil

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40 meters is quite a long run. I'd use a DA. But if you use only a cable, I'd recommend using a true RG59 gauge cable for each signal, just as you would for a RY-BY-Y cable run.

Steven Bradford
Lost without my crimper
Seattle

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I’d say maximum lengths using the best quality s-video cable is 60 feet (18m), after that you will notice some picture degradation.

Here is a chart of loss of signal based on frequencies per hundred feet.

Mhz db/hundred feet
1 .6
3.6 1.2
5 1.4
7 1.7
9 2.0
0 2.1
30 3.8
50 5.1
100 7.6

For longer lengths I would suggest running coaxial cable (RG-6) and purchase adapters to convert the coax cable's F-type ends to S-video. You can get 100 feet or so (30m) with this method. Longer than that I would suggest a distribution amplifier. I use them in industrial video applications and find no problem with doing so.


Walter Graff
Producer, Director, Creative Director, Cinematographer
HellGate Pictures, Inc.
BlueSky, LLC
www.film-and-video.com

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Walter Graff wrote:

>I¹d say maximum lengths using the best quality s-video cable is 60 feet >(18m), after that you will notice some picture degradation...

What type cables are you basing that on? Elite Video sells (or did sell, haven't checked lately) S-Video cables that were 18 gauge, 100 feet long. I've been using them for several years with good results (but haven't measured the signal loss, if any.)

Wade K. Ramsey, DP
Dept. of Cinema & Video Production
Bob Jones University
Greenville, SC 29614

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>What type cables are you basing that on? Elite Video sells (or did sell, >haven't checked lately) S-Video cables that were 18 gauge, 100 feet >long.

High quality ultra-low capacitance designed cables may offer you more length but there is no such thing as a cable that does not have signal loss. You may still see a picture but you are losing something in lengths that long. I posted measurements of loss for good quality cables at various frequencies in my previous post.

I have seen S-Video cables in lengths up to 150 feet. I understand you can get a signal with a s-video cable up to 1000 feet long. The high end 100+ foot cables usually contain individually shielded low-loss silver-coated oxygen-free copper wire with ferrites and three layers of shielding including individual y/c stranded shielding, and overall shielding and cost up to 200 dollars. Some of the real high end short ones are nitrogen gas injected. The stated maximum suggested by the respected cable manufacturers is 35'. My videophile friends wouldn't think of running a s-video cable more than 8 feet without an amp but then again it's all about what you don't mind. One guy I know uses s-video baluns connected to cat5 and has probably over a 1500 feet of cable in the entire system which connects between two buildings on his property.

Walter Graff
Producer, Director, Creative Director, Cinematographer
HellGate Pictures, Inc.

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