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Old March 11th, 2004, 03:06 AM   #1
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Best/Near Lossless A/V cable when running over 100+ feet

What is the best (meaning the least loss in video/audio quality) cable and connector type you can use when running a A/V signal 100+ feet. I would like to avoid using some type of signal booster if I can but if not let me know.

So what the best A/V cable for 100+ foot runs?

RCA?
S-VIDEO?
BnC?
or ???

Thanks!

-Brett Erskine
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Old March 11th, 2004, 06:41 AM   #2
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I would use a high quality coaxial cable from a manufacture like Belden. I prefer Canare connectors, ideally BNC so they don't accidentally come loose.
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Old March 11th, 2004, 04:20 PM   #3
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I've run S-Video 125 feet using the twin coax cable sold by Markertek and the crummy S-video connectors they use.

The video was a backdrop for a stage play and was in black and white but quite large. Quality looked OK but it wasn't color.

I've tried 75 feet with lots of Radio Shack S-Video cables in series through their barrel-connectors from a camera to a projector. It wasn't a pretty sight.

I'd go with a set of line drivers were I you and the event is important or you don't want to be embarassed.

That said, if I had to take color over a long distance it would definately be great coaxial cable and the Canares. I just rebuilt a complete TV studio with the Canare BNC connectors with the Canare-recommended cable and the signals are pristine. But understand we start with 800 line studio cameras and ultimately feed a pro S-VHS deck. Every bit of loss visibly hurts.
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Old March 12th, 2004, 08:36 AM   #4
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Jeff's on the mark. Get some quality coax with bnc connectors. Put some BNC to RCA adapters on the end to connect it to the camera.

With quality coax you shouldn't need a signal booster until you go over 1000 ft.


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Old March 12th, 2004, 09:34 AM   #5
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Question: Are you saying that a composite video signal run through coax is better than an Y/C (Svhs) run through a good quality cable at distances of 100-150' ?
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Old March 12th, 2004, 01:45 PM   #6
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I'm saying that you won't notice a difference.

Also, you consider an upgrade path. If you ever have to rent or purchase a full size camera then you won't find any svhs outputs on it and you'll have to go to bnc cable at that point anyway. Go really high end and your still on bnc for that distance because SDI runs down bnc coax.

So for a lot of reason's svhs should stay in an edit bay and you should use coax in production work.

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Old March 12th, 2004, 02:05 PM   #7
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Ben,

Both of my pro cameras have S-video out as do the prosumer cameras.

I'd not go BNC to RCA adapter because the RCA adapters are not 75 ohms and will cause two reflections (ghosts) in your video.

Canare makes RCA cable connectors that are true 75 Ohm and work very well.
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Old March 12th, 2004, 02:12 PM   #8
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Thanks - I have done both. I have used coax when connecting a "professional" camera to a switcher, and used S when using cameras like my xl-1 and gl-2. Do you think the composite output of these cameras is robust enough to send clean signal over coax?
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Old March 12th, 2004, 02:20 PM   #9
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Oh yes. But the limit is how much degredation of signal quality can you accept. At some point, a set of line-driver/line-receivers is going to be necessary.
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Old March 12th, 2004, 09:28 PM   #10
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I'm going to still disagree on both counts of the cable format and the line drivers Mike.

I work in network broadcast sports and we only use triax and coax. I've never made a run of svhs cable. And signals don't get boosted. We run hundreds of feet of it a week without boosters and the signals come in clean. In fact every connection at the truck is coax.

Since it's good enough for the viewers at home to enjoy a clean hd picture then I'd say that it's good enough for any local video production.

And a signal amp for a short run of a few hundered feet? That's just a waste. A humbucker could be needed if you get roll but not a signal amp on such a short run.

As for the broadcast camera's that support svhs that's questionable. Maybe a Sony 5xx or a JVC-5000xx but not a full broadcast camera. Sony 950, Ikegami full size, Phillips... They don't have svhs out.

This is really an endless debate about which cable is better etc. In the end, if your happy with how it looks then what difference does it make which cable you used?

Ben
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Old March 12th, 2004, 09:52 PM   #11
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Let me guess you don't run RG-58 coax when you run the cables from the HD cameras to the truck, Ben. That's probably what is going to be used. It is more lossy than what you use. And Brett didn't specify length, just a statement of over 100 feet.

Having designed and built a few TV studios I can tell you that at the opposite end of the spectrum from your super pro equipment, signals are not as robust and the cables generally aren't as good.

Phase shift and timing changes down inexpensive coax is apparent and is readily measurable and the less power the driver circuitry has, the worse the effect.

Ultimately only Brett can determine if plain cable at the length he has to run is acceptable.

Probably, if he is running just 100 feet and is just feeding a display, the quality will be acceptable. But it won't be the same quality the camera pumped into the source end.

And you are completely correct about happyness being relative.
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Old March 13th, 2004, 09:28 AM   #12
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One could also use the digital signal and convert at the receiving end.


A firewire repeater (electronic):
http://www.gefen.com/kvm/product.jsp?prod_id=1329


A firewire repeater (fiber optic):
http://devicebaystuff.com/opticis/m4100xx.html


The fiber optic variant is spendy, but hundreds of meters can be spanned.


I have no connection to the sellers/manufacturers of these products.
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