HD-SDI cable

Buck Forester

Buck Forester

Well-known member
I have the Sony EX1 and I would like to get an HD-SDI cable. I did a search here, and Google, and I'm not finding where I can buy this cable? I looked at B&H and it came up with a 100' cable. I only need a few feet... I just want to hook it up directly to my monitor for some motion testing, and I will probably be getting the Convergent Design NanoFlash so I don't need a long cable. This is a basic and probably stoooopid question, but where do I get HD-SDI cable? Thank you.
 
Thank you, Willis. Excuse my ignorance, but is SDI cable the same as HD-SDI? Or is HD-SDI just the "port" reference on the camera? Any specific brands or type better than others? I flunked 'wiring' in college. But I make a mean hamburger.
 
You can output HD or SD over SDI... Same thing. It's like firewire. You can output multiple things over it. And it carries audio with it as well.
 
Buck, I declare open season on YOU!!! For having access to an uncompressed HD-SDI recording solution and putting us all through the ringer with this nanoflash stuff!

*POW!*
 
Worth noting that while HD-SDI, SDI, Analog Video (Composite, etc..) all travel down the same 75Ohm Coaxial cable, they have different bandwidth requirements.

Though a composite signal will work over just about any crappy coax, SDI needs better quality cable to work reliably over any distance. And again; HD-SDI needs better cable still.

HD-SDI has a signal rate of 1.5Gbps .. meaning that the cable must be able to carry a 3GHz signal. This is considered the minimum rating for "HD-SDI"

Short hops (a couple of feet) can normally survive even over lower quality cables if necessary.


- Mikko
 
PerroneFord said:
Buck, I declare open season on YOU!!! For having access to an uncompressed HD-SDI recording solution and putting us all through the ringer with this nanoflash stuff!

*POW!*
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Ha! Just because I have access to it doesn't mean I know how to use it! Yet. I figure when I finally figure out how to use all this stuff, it'll be outdated.

mikko, thanks for info. I'm printing out this thread before I head to the store... hopefully all these specs are on the packaging so I know what to get.
 
weixiang623 said:
i was just @ Coffey Sound, they got a lot for video & audio sdi cables of all lengths.
www.coffeysound.com
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Man, I'm with Buck. There's nothing out there under searches for HD-SDI. Not at coffeesound, not at B&H (which only has like two options at 100').

I don't know what to search for. BNC cable? SMPTE 292M? 3GHz? The damn Panasonic specs don't even say any more than 'HD-SDI.'

B&H has to have a 30' foot cable. I just can't seem to find it.
 
RG6 with BNC ends is what you need. Good stuff from Extron or Belden.

This isn't consumer stuff which is probably why you're having issues with it. TV studios are full of this stuff, and often the runs are LONG. You use this stuff to feed video villages on movie shoots too. And those runs are LONG also.

Bringing SDI into the consumer world is pretty cool, but there's not been any real education for the consumer guys on this stuff I don't think.
 
Thanks Perrone

Good info, and it's nice to be able to not sound like an idiot when calling around to order something.
 
the other thing I'd like to find is whether there are cable options out there which are a little more flexible than your usual, very stiff coax cable. I was looking doing web searches, and found one cable that advertised 'greater flexibility,' but lost the link. It's usually pretty stiff, I imagine.

The idea behind HD-SDI is that instead of three cables, which analog HD uses, a single cable serves as a pipeline for the torrent of data that is uncompressed HD....But all HD-SDI outputs are not created equal. At minimum, an HD-SDI signal must contain uncompressed video data. Optionally, it can also carry audio and timecode — eliminating two more cables — if these are first “embedded” in the HD-SDI data stream.
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Both the HD and SD serial interfaces provide for 16 channels of embedded audio. The two interfaces use different audio encapsulation methods--SD uses the SMPTE 272M standard, whereas HD uses the SMPTE 292M standard. In either case, an SDI signal may contain up to sixteen audio channels (8 pairs) embedded 48 kHz, 24-bit audio channels along with the video.
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Lor said:
So let me confirm this. HD-SDI cable carries both audio and video, correct?
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It CAN, but only if the camera supports such. For example, on the original Canon XLH1, the HD-SDI only carried video, it didn't have embedded audio or timecode. HD-SDI as a standard is capable of including both, but on that particular camera they didn't enable it.

On an EX1, or HPX170, or most any other pro cam, you'll get embedded audio and timecode in the HD-SDI data stream. Just be sure to check before assuming that it'll be there.
 
I think most users of this board have a good deal of experience. But for those just getting into DV filmmaking, there's a lot of good info to be found / shared here, and in that regard, I'm just sharing here.

After a bit of research, I've found the following, but the more pro you get, the more vague the info seems to be:

-The standard subset of HD-SDI is a SMPTE standard, specifically: SMPTE 292M HD-SDI 1.485 Gbit/s, and 1.485/1.001 Gbit/s 720p, 1080i
-It's apparently only good for 1080i, or 720p.
-If you want to output 1080p, you need to go to different standard, which can need two cables and is called: SMPTE 372M Dual Link HD-SDI 2.970 Gbit/s, and 2.970/1.001 Gbit/s 1080p
-So I don't know if the HPX170 can output 1080p through one cable. Any of the pros know?

-My research was about a cable run of 25ft, and I was told that most RG6 and RG59 would work fine for my need.
-RG59 is thinner, and has some options for being more flexible.
-As previously stated, when doing this research, you'll often be looking at a cable category called 'BNC to BNC' for the ends of a single cable.
-I found this flexible RG59 cable that will pass a SMPTE 292M signal after some difficulty at B+H: http://www.bhphotovideo.com/c/product/351526-REG/Canare_DBB59_DBB59_25B_BNC_to_BNC_SDI_.html#features
-A heavier (probably better) RG6 option at Extron (who were helpful over the phone), but I'd need to find a reseller:
http://www.extron.com/product/product.aspx?id=singlecondrg6hrbmbmc&search=26-383-04

And be aware of this:
The origin of the RG designations is in old, long-obsolete military specs; RG stands for "Radio Guide," and the RG numbers are completely arbitrary. Most cables today are referred to as RG-# "type," meaning that they don't strictly conform to the original Radio Guide specifications. The result is that the RG designations are so non-specific that it's not really possible to say how a cable will perform just from knowing its RG number. We see a lot of discussions on message boards and the like where it's asserted that "RG-59 has lower bandwidth than RG-6" or "RG-59 is not as well shielded as RG-6"; statements like that are never really strictly correct. They may be correct as between one particular RG-6 and one particular RG-59, but not between others.

Take RG-6, for example. The only thing one can say generally about RG-6 type coaxes is that they have an 18 AWG center conductor. An RG-6 might be a cheap generic CATV coax, designed strictly for economy, with a thin aluminum braid and a copper-coated steel center conductor; it might be a better-grade CATV coax, with an aluminum "quad shield" arrangement; or it might be a precision serial digital video coax like Belden 1694A, with a dense copper braid and double-foil shield, solid copper center conductor, nitrogen-injected PE foam dielectric, and extremely broad bandwidth and tight impedance tolerance. When people ask, "can I just use RG-6 for this application," the only correct answer is a question: what do you mean by "RG-6"? High-bandwidth serial digital video and cable TV distribution may both use RG-6 type cable, but that doesn't mean that the cable for one is necessarily suitable for the other.
http://www.bluejeanscable.com/articles/rg6.htm
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Just out of curiosity (and almost zero electronic knowledge) - is this realy digital data that gets transmited by the SDI?

I mean - it´s a copper cable not a fiber optic thingy. Can you transmit digital on copper or do you only use a discription (sine wave) of a digital (square wave) signal. Can current live in a square wave at all?

Sorry for the bizarre questions, maybe I´m totaly off.

Frank
 
Postmaster said:
Just out of curiosity (and almost zero electronic knowledge) - is this realy digital data that gets transmited by the SDI?
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Yes.

Postmaster said:
I mean - it´s a copper cable not a fiber optic thingy. Can you transmit digital on copper or do you only use a discription (sine wave) of a digital (square wave) signal. Can current live in a square wave at all?
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I'd say a true sine wave would be MUCH harder to produce than a square wave. Pulse on / Pulse off is trivial to do. Isn't Firewire a digital signal over copper?

And just to throw fun at this, SDI cable is also available in fiber-optic for those that need the length and signal quality.
 
I would advise everyone to buy their SDI cables at www.markertek.com I have used them for years and they have all kinds of stock SDI cables and lengths and they have a cable shop and will make any weird, bizarre cable from scratch that you can think of.

Oh yeah, main office is in NY but they have a warehouse in Las Vegas so it is easy to get overnight to west coast, not have to pay sales tax (unless you are honest enough to pay sales tax on all of your internet purchases like I am sure all of us do at the end of the year, right? ;-)

Highly recommended.

Dan
 
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