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ok to replace coax with ribbon cable?

ok to replace coax with ribbon cable?

ok to replace coax with ribbon cable?

(OP)
I'm looking to send a baseband(I think this is the term - It is a standard NTSC security camera) video signal over a short run of about 5ft. DC power and Audio will also be running along the same length and I was looking to just use a single ribbon cable (28AWG) rather than source a composite coax / other cable.

What types of problems might I run into for a ribbon cable carrying baseband NTSC over a length of 5ft?

Thanks,

RE: ok to replace coax with ribbon cable?

1) Radiating all over the place(men in black van will come and take you away).

2) Picture that may waver and change especially when anyone moves in the near vicinity.

3)??

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: ok to replace coax with ribbon cable?

(OP)
That is pretty much what I was afraid of. Would sending the signal over twisted pair be of any help?

RE: ok to replace coax with ribbon cable?

(OP)
Hmm... I can't find the right coax composite cable, but I am able to find a 5-coax bundled cable. Would you know of any issues with running power (12V / 1A) and audio signals over the separate coax lines? As always, thanks!

RE: ok to replace coax with ribbon cable?

As long as the power isn't too noisy I would think it should work fairly well.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: ok to replace coax with ribbon cable?

The security type cameras I've got all use what looks remarkably like telephone extension cable.

Yards of it. 6 yards on the longest.

And they are all CE marked for what that's worth...

No one has come to take me away yet...

Seems to work ok, but the cameras are monochrome.

RE: ok to replace coax with ribbon cable?

Why not search for some of the specialised composite cable such as made for satellite dishes and CCTV? A quick Google found this:

http://www.hometech.com/techwire/coax.html#HT-RG59182W

- only one coax but reasonable power cores. There are lots of different types out there.

RE: ok to replace coax with ribbon cable?

(OP)
I've done a search and couldn't find a 1coax+6additional, otherwise, that would be my first choice. I did a quick test and it appears normal wires don't cause the video to degrade visibly over a short distance, even while touching / fiddling with the wires. I realize this in no way proves that it is ok to use plain wire. Also I have not looked at RF emissions yet.

RE: ok to replace coax with ribbon cable?

I have successfully fed high resolution RGB + drives + syncs down a flat ribbon cable for about six feet with perfect results. The secret is to solidly ground every alternate conductor at both ends to a ground plane. There were video components visible to 350 Mhz on my spectrum analyser. No sign of crosstalk or reflections either. If you possibly can, arrange for the driving, and especially the load impedance to be as close to 110 ohms as you can make it.

No sign of electrical interference, either incoming or outgoing. I originally approached this with much fear and apprehension, but the results were beyond my wildest hopes. It was for a highly specialised commercial computer control desk that sold for around $900K each, so poor quality pictures were just not acceptable.

The video cable driving the computer monitor you are watching right now is almost certainly just a bit of crap poorly screened multi core bundled cable, about maybe a yard long. And I bet the picture looks pretty sharp !

RE: ok to replace coax with ribbon cable?

Warp, that sure beats my 12 Mbps data that I sent down a ribbon cable successfully!  Grounding every other connector is very important.  

On a side note, what kind of SNR do you need for a decent video signal?  Before I get a lot of answers about them, I know there are limitations in phase and IMD but those don't concern me at the moment.  

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