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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Will a regular BNC cable carry an HD-SDI signal?

Thor Wixom

Thor Wixom

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I just bought a BNC cable from a salesman who assured me that it would carry an HD-SDI signal.

I'm trying to capture footage from my Red through the HD-SDI port(s), and/or the preview port, to a Matrox Axio.

I'm not having any luck with it. I'm trying to find the missing link, and I suspect it may be the cable.

-Thor
 
Thor Wixom said:
I just bought a BNC cable from a salesman who assured me that it would carry an HD-SDI signal.

I'm trying to capture footage from my Red through the HD-SDI port(s), and/or the preview port, to a Matrox Axio.

I'm not having any luck with it. I'm trying to find the missing link, and I suspect it may be the cable.

-Thor
Click to expand...
It does, a simple a BNC cable does transmit HD-SDI but if you want 444
you might need two of them.
 
Stuart English said:
What signal are you trying to capture - 720p or 1080p ?
Click to expand...

1080p.

The 720p mode on the Axio LE does not allow you to capture through HD-SDI. I think it was designed to only interface with .MXF files or with firewire in 720p, which would not require HD-SDI capture.

-Thor
 
How long is the cable? It should be fine except on very long runs. Have you checked the cable works with other video (even SD video to a monitor) to prove continuity? Either that or buzz it out with a continuity meter.
 
Try using RG6 insted RG59 (the normal one for video BNC), RG6 have double shield and it´s better for long runs. 75 OHMS too.

5204_1215774661.jpg
 
Thor,

I hope you are well. All cable is not created equally.

Check out Gepco, or Joseph's electronics, they have a wide selection of HD & SD cable. Conductor size and insulation are the main factors when choosing cables for HD and distance.

Best Regards
David Birdy
 
1080p Output

1080p Output

O.K if 1080p - here is a checklist.

1. 1080p is only available in playback, at other times the HD-SDI outputs are 10 bit 4:2:2 720p.

2. Set SYSTEM / SETUP / PREFERENCES / PLAYBACK to 1080p

3. The " PVW " output is 10 bit 1080p 4:2:2 but the two connectors labeled " HD-SDI " provide a 10 bit 1080p RGB 4:4:4 signal. Therefore you probably want to be connected to the PVW output.

4. The signal format on the HD-SDI outputs is Progressive, not Progressive Segmented Frame (PsF)
 
Stuart: I'm sure this has been asked and answered before but seems like your online now so is the playback 1080P coming out of the HDMI as well and is it likely to play on a 1080P TV bought in the last six months - or do I need to hook it up to a computer monitor HDMI to DVI? (I don't have an hd-sdi monitor)

Also FYI, we ran the live output 150 feet over some fairly standard RG-6 to an HD-SDI monitor on an underwater shoot a few weeks ago.
 
HDMI output

HDMI output

is the playback 1080P coming out of the HDMI as well and is it likely to play on a 1080P TV bought in the last six months
Click to expand...

Yes, HDMI on 1080p playback is now enabled in Build 16 Beta builds, so give it a try.
 
Stuart English said:
O.K if 1080p - here is a checklist.

1. 1080p is only available in playback, at other times the HD-SDI outputs are 10 bit 4:2:2 720p.

2. Set SYSTEM / SETUP / PREFERENCES / PLAYBACK to 1080p

3. The " PVW " output is 10 bit 1080p 4:2:2 but the two connectors labeled " HD-SDI " provide a 10 bit 1080p RGB 4:4:4 signal. Therefore you probably want to be connected to the PVW output.

4. The signal format on the HD-SDI outputs is Progressive, not Progressive Segmented Frame (PsF)
Click to expand...

Stuart,

I set the camera to your recommendations.

The Axio only has one HD-SDI in, so it's obviously set up to only do 4:2:2.

The progressive vs. PsF issue may be the problem.

We've looked into this far enough. Thank you for your time. You don't need to worry about following up any further.

-Thor
 
Thor Wixom said:
The cable is a TecNec RG-59/U. I went to their website and they didn't list the ohm rating. It's 50 feet.

Here is the link:

http://www.tecnec.com/SearchProduct.asp?item=RG59-100&off=0&sort=prod

-Thor
Click to expand...

Pretty sure RG59 is always 75ohm, which is what you want:
http://www.bluejeanscable.co.uk/articles/rg6.htm

50 feet is well within typical lengths for RG59 HD-SDI too:
http://broadcastengineering.com/mag/broadcasting_highbandwidth_coaxial_cable/

According to SMPTE 292M specifications RG 59, RG 6, RG 7 and RG 11 are all suitable for HD-SDI interfaces running at 1.458 Gbs (Gigabits per second).
 
Impedence isn't the issue; Mhz is. The cable should be rated for at least 3.5Mhz. It will say so directly on the jacket of the cable. If it does not then it should not be used for HD-SDI.
 
Thanks, Mitch. Very helpful.

-Thor
 
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