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Pro SD cable BNC line question


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#1 Michael Desiderio

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Posted 21 December 2014 - 01:15 PM

Just curious, is the standard pro SD cable sufficient to provide HD-SDI if I were to axe the POWER/VID wiring?  The top stage I would wire the old video BNC solely to a 75ohm female BNC, and at the bottom I would add a 75ohm BNC as well and cut the video away from the pro 5 pin monitor out. 

 

Anyone have any luck in doing such a mod?

 

Of course I could always go the nuclear option and drill out the video pin from the lemo socket and feed a wire straight through it......but that might be a little overboard.


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#2 Jarrett P. Morgan

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Posted 21 December 2014 - 02:55 PM

As far as I know it is not. I believe there are issues with impedance and shielding in the SD wiring (that are perfectly fine for a composite signal) that will not allow it to work with HD. That being said, I have not tried it myself. I did do an HD upgrade, but ran an independent mini-coax down the barrel, connected with RP-SMA connectors. It did require a bit of mechanical modification to make the cable fit through the joints in the rig, but was fairly small and did not harm the integrity of the rig. What rig do you own?


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#3 Michael Desiderio

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Posted 21 December 2014 - 03:03 PM

As far as I know it is not. I believe there are issues with impedance and shielding in the SD wiring (that are perfectly fine for a composite signal) that will not allow it to work with HD. That being said, I have not tried it myself. I did do an HD upgrade, but ran an independent mini-coax down the barrel, connected with RP-SMA connectors. It did require a bit of mechanical modification to make the cable fit through the joints in the rig, but was fairly small and did not harm the integrity of the rig. What rig do you own?

 

It's a pro rig, with the standard 8 pin pro lemo connector.  Not sure what you mean by mechanical modifications to make the cable fit through the joints in the rig.

 

Are you saying you ran a mini-coax straight through the female lemo from one end out to the other end?  And capped it out of the coiled cable bundle and connected it to a regular coax and ran that alongside the coil bundle?


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#4 Jarrett P. Morgan

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Posted 21 December 2014 - 03:36 PM

Well, I have a MKV upper junction box, so it is slightly different in mechanics than the pro 1 or 2. I think the pro 1 rig would be easiest to do at the top since it is hard-wired in. There needed to be a hole in the upper junction box to allow the cable to pass through (and the RP-SMA connector so I can take the rig apart) and the bottom needed to be dremeled out a bit to allow the cable to pass as well. I can take some pictures and post them if you'd like (though my rig is a bit of a frankenrig, so I don't know how much you can glean from them)

 

I ran the mini-coax around the connector on both the top and bottom. I just heat-shrinked the mini-coax to the outside of the coiled cable the whole way up the post. I think normal sized coax would be too big to fit in the post. Unless you have a 2" post maybe. The cable I used wasn't perfect though. If I did it again I would go with Belden 179DT I think. It is what Alan Rencher uses for some of his mini-BNCs I bought and I really like it for size and flexibility 


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#5 Michael Desiderio

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Posted 21 December 2014 - 03:59 PM

Ah I see. I don't believe it's possible to do it this way.  Have a pro post with bayonet mount, and the upper j-box's lemo connector pretty much fills the entire space.  I thought maybe you passed a very thin gauge coax directly through the female lemo or something.


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#6 Jarrett P. Morgan

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Posted 21 December 2014 - 04:20 PM

Ah, yes. I am actually not very familiar with the Pro bayonet connectors unfortunately.

 

My top stage uses a 2B 307 connector rather than the 3B 308 connector of the pro. It is smaller and lets me get around the connector.

 

I think the only way to do that with the newer style is to switch them out to be the 3B 856 style. The issue with drilling out the video conductor is then I think you couldn't take it apart without completely disassembling the HD line.


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#7 Jarrett P. Morgan

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Posted 21 December 2014 - 04:23 PM

Unless the 3B 308 has enough room in the middle to fit the rpsma connector through it if drilled out.... That may work.


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#8 Martin Stacey

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Posted 21 December 2014 - 05:59 PM

Can you post some photos of how you drilled the connections out Jarret please. I've been considering something similar for one of my old rigs.
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#9 William Demeritt

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Posted 21 December 2014 - 06:17 PM

As someone who did some modification to my UJB and LJB in attempts to do what sounds like the same thing, I'll just say this: dude, just pay for the HD upgrade and sell off the parts. I did a number of attempts at the mods, and in the end, I just did the HD upgrade anyway. 


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#10 Jens Piotrowski SOC

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Posted 21 December 2014 - 06:26 PM

or, buy yourself an Aja V2analog for $350 and be done, seriously you don't need HD (1920x1080) on a 7" steadicam monitor.....none of them are anyways....


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#11 Michael Desiderio

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Posted 21 December 2014 - 09:46 PM

As someone who did some modification to my UJB and LJB in attempts to do what sounds like the same thing, I'll just say this: dude, just pay for the HD upgrade and sell off the parts. I did a number of attempts at the mods, and in the end, I just did the HD upgrade anyway. 

 

 

Oh I can see that this is a no turning back situation if I decided to mod the analog stuff.  It's sort of a situation where I'm looking at either 30 bucks of parts and a no-turning-back modding to get *just* HD video (and, I believe, lose my camera/power combination ports in the process), or spending $1K+ on the HD upgrade.  I mean, I can't even find the part numbers for the 18/19 pin lemo upgrades (if they even exist for end user purchasing).

 

 

or, buy yourself an Aja V2analog for $350 and be done, seriously you don't need HD (1920x1080) on a 7" steadicam monitor.....none of them are anyways....

 

 

Why the HD video hate?  Can see more stuff, can pull your own focus if you have to.  There's .... literally no downside.


Edited by Michael Desiderio, 21 December 2014 - 09:47 PM.

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#12 Jarrett P. Morgan

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Posted 22 December 2014 - 01:15 AM

Michael, 

the connector is a FGG.3B.856.CLADXX (where XX is the cable size). But it is not a connector you can do yourself. The coax portions of it are crimp and you need a special tool (as far as I know).

 

I will post some pictures of it when I get back into town after the holidays. 

 

 

That all being said, I really enjoyed doing the work on my rig to upgrade it to HD. It works and I now know my rig even better. To be fair though, it is a bit of a frankenrig. 


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#13 Jens Piotrowski SOC

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Posted 22 December 2014 - 11:03 AM

Just saying, the effort (cost) needed to sent HD-SDI through your post is not always worth it. It does not improve your operating. Color helps you more than resolution.
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#14 Tommy Stork

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Posted 25 December 2014 - 02:28 PM

Hi Michael,  I do the wiring at PRO and Jarrett is correct, you cannot hack the video line and turn it into an HD line. From what I know the data packets get lost throughout the unshielded wiring and solder between the upper and lower junction box. I don't have an old junction box in front of me to know for sure, but I also don't think there is enough room between the lower junction box housing and the junction box connector to run anything like a mini BNC.  I'm kind of adventurous when it comes to this stuff so I know it'd be fun to do if you decide to do it.  Whether or not the end result will be successful is another matter.  Have you talked to David Hable (sp) at Cramped Attic yet?  He has done quite a few upgrades and may have some good information for you.

Just curious, is the standard pro SD cable sufficient to provide HD-SDI if I were to axe the POWER/VID wiring?  The top stage I would wire the old video BNC solely to a 75ohm female BNC, and at the bottom I would add a 75ohm BNC as well and cut the video away from the pro 5 pin monitor out. 

 

Anyone have any luck in doing such a mod?

If I understand what you mean, you do lose the Lemo 1S 12v only connector if you upgrade to a cinelive but you still have 2 larger Lemo 2B power connectors for camera power. 

 

and, I believe, lose my camera/power combination ports in the process), 


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#15 RonBaldwin

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Posted 25 December 2014 - 05:40 PM

I'm with Jens on this. How the hell did all those great shots get done with an SD 3" green monitor!?
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