Rack Building BNC Cables

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Rack Building BNC Cables

Hi,

I am rebuilding my Video Rack / PPU and can't face re-using the majority of the coaxal cabling from the existing rack.

Can anyone recommend a good cable for SDI links inside the rack - Ie thin, flexable, and easily to crimp?

Thanks,

Tim

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West Michigan
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Belden 1855a

Belden 1855 A  is what i use in rack and for anything less that 20' or approx 4 meters. Have used it for years and never had any issue.  purchase the proper crimp tool and you are good to go.

 

https://www.markertek.com/product/pal-1366/greenlee-pa1366-crimp-tool-fo...

 

 

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Molde
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Just remember that you need a

Just remember that you need a good quality, larger diameter cable from your patch panels to your mixer / router - as this will otherwise seriously limit your available cable length outside the rack (Got burned by this when I was starting out).

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Thanks,  Does good quality

Thanks, 

Does good quality always have to mean large diameter?

Tim

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cables

Well not always.. I boughed 12G sdi capable cabling for my OBV and some test runs.. 

 

But at my Phabrix some 10 year old Belden Briliance 1855 cable which is thinner, does not have 12G connectors and just rated for 3G does a better job of keeping eye opening on 12G sdi video while the special 12G cabling doesn't.. 

So i was amazed with the results produced by this Belden 1855 ENH 0.6/2.8

 

Offcoarse long runs it won't be that good.. But for short patch inside racks i like it now.

Daniel Wittenaar

Xtreemtec Media Productions

The Willows Developments

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Nice one. The Belden 1855 ENH

Nice one.

The Belden 1855 ENH does look like a good balance between O.D and distance going by this Canford chart:

https://www.canford.co.uk/Technical/Article/MaximumTransmissionDistances?portable=true

 

Tim

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Another vote for Belden 1855

Another vote for Belden 1855 ENH here. I'd also recommend Neutrik rear twist BNC ends to go with it as they make it far easier to patch into Blackmagic's high density BNCs and the ends are just far more pleasant to use than any of the "standard" BNC types. You don't need the Neutrik crimp tool, but I'd recommend investing in their crimp tool anyway as its very well made and easier to use than other types which don't have the parallel jaws action (I far prefer my neutrik crimper over my Paladin 8000). If you have any number of cables to make than i'd also recommend getting a Neutrik Coax Stripper as it ensures your ends are correctly prepped whilst being a whole load faster than trying to manually measure and strip them. 

These ends and tools are not the cheapest, but the ease of use and long term reliability makes them well worth the small premium on the inital outlay. 

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Great, I ordered a roll and a

Great, I ordered a roll and a load of Rear Twist earlier today.

I discovered the rear twist a couple of years ago and they are great!

I do have a Paladin tool and cable stripper which work ok but probably worth investing in the Neutrik kit for this amount of connections.

Tim

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Molde
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Re: Cable
Tim Gregory wrote:

Thanks, 

Does good quality always have to mean large diameter?

Tim

 

Not necessarily - but most of the time. And it also depends on what you mean by large :) 

The 1855a recommended here has a loss characteristic of 9.31dB / 100ft @ 750 MHz (half the bandwidth of HD-SDI). According to SDI specifications, 20dB is maximum guaranteed loss characterics a device should be able to recover a signal from, although most newer devices have a better frontend and can do more. This means that your signal can travel 220-ish ft (70-something meters) without being amplfiied or reclocked on this type of cable. Since you only have a small part of the cable in this quality, you probably won't be this limited, but it WILL affect your signal quality (not image quality), and the higher bandwidth you go, the more distance you lose.

 

Of course, most Belden cable can pass even up to 12G-SDI as it is good quality cable, but at that bandwidth, 1855a would probably drop out after less than 20 meters ( loss at 6GHz = 28dB / 100ft => 20dB @ ~60ft = ~20m). When TI and most other SDI chip vendors rate their receivers for cable length, they use Belden 1694a in the entire signal chain.

Also, in Belden-speak, a coax cable with the suffix -A is generally meant for install etc and is quite stiff, while -F is more flexible and is designed for use to cameras, in racks etc in my experience.

 

All tech data fetched from the datasheet: https://catalog.belden.com/techdata/EN/1855A_techdata.pdf

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The Belden 1855 ENH is the

The Belden 1855 ENH is the sort of OD I was looking for - around 4.5mm.
The flexability on the roll that I have is fine for inside the rack, I am not sure I would want to use it for general cabling. 

I decided to rebuild my video rack and cut down from a 26U to 16U - Making good progress but regretting not getting a case with a bit more depth! 

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nice looking rack Tim. is

nice looking rack Tim. is that a router panel above the hyperdecks? i don't recognize the brand if it is...

 

for the rest of the group, we too use belden 1855a almost exclusively for rack wiring. we have a 12U rack with a 2M/E and a 72x72 videohub and 72 BNC I/O panel. i can't even imaging trying to stuff large diameter coax in that (little) space.

Greg Bellotte
owner - MambaFiber.com
FaceBook.com/MambaFiber

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Thanks. I used a standard

Thanks.
I used a standard rack case and hacked the lid into it...

The router is a Codan NK series 16X16.
A friend of mine works on IT support and installation and they pulled it out of a client's rack when replacing with new conferencing kit. He sent me some pics and asked if I was interested in having it.
Codan was brought by by Ross in 2010 so it must be fairly old, but looks brand new and is beautifully constructed.
There is an additional networking interface so 3 X 1u units in total.

Tim