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Is an SDI cable the same as a Composite cable if they both have BNC?
Hello,
Thanks in advance for reading this!
Can you tell me if a standard composite BNC cable can be used instead of an SDI cable (also with BNC) to connect a digibeta deck to other systems that accept SDI?
I really appreciate any help!
Kirk
Arthouse Films -
5 Replies
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it will likely pass signal but NOT RECOMMENDED!
you need to get SDI rated cables. -
Cool. Thanks so much for the clarification!
Kirk
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Personally I’ve never had a problem using bog-standard “standard-def” professional BNC cables. SDI is digital and with inferior cables you would see sync or picture breakup (pixelisation) problems if you had a dodge cable. I’d say save your money and get good standard BNC cables. Markertek in the US sell an excellent range of high-quality cables.
Peter
Peter Corbett
Powerhouse Productions
http://www.php.com.au -
no one appreciates cables until they start having problems. Cable is rated for bandwidth, not HD or SD, and hi def signals (like 720p and 1080i) run at a certain bandwidth or frequency. Newer technology like 2k and 4k run at even higher bandwidths. All digital signals (SD and HD) are square waves, and these square waves start to break down and become unusable, if not transmitted properly. This is why you see “eye pattern” functions on SD and HD waveform monitors – to see how screwed up your digital video signal is.
With this said, if you use crap cable, your square waves become noisy – particularly after long distances, and when you use cheap cable – you don’t even get an image (the signal is too noisy, and the equipment can’t decipher the square wave digital signal). This even applies to super hi quality video cable, after long distances. I never appreciated any of this, until I had to run HD signals back and forth between an edit room and a machine room. After 200′ of cable (cheap cable) – there was no picture – I thought I had a problem with the connectors, but the square waves just broke up ! Using better quality cable solved the problem.
If you use cable made from Belden 1505A, Belden 1694, or Gepco VPM-2000, you will have no problems, for up to 300′. For short distances (like 10 – 20′), cheap crap cable will work just fine, even for HD signals (and I mean cheap crap coax RG-59 type cable – not Radio Shack RCA audio cable with BNC adaptors on it !).
Markertek in the US is an excellent source for all this stuff.
bob Zelin
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Thanks for the details, Bob. I was looking for this info just the other day.
Very useful.
Craig
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