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Making Stiff Cables Softer


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#1 Michael Nelson

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Posted 05 December 2009 - 11:20 PM

I bought some SDI cables to carry with me as a "just-in-case". The problem is that they are very new and hold their round coil VERY well. So well that instead of laying flat on the ground, it lays in coils and MUST be taped down.

Is there a way to fast track the process in loosening this rigidity and make them lay flat?
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#2 Kar Wai Ng

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Posted 06 December 2009 - 10:02 PM

If the cables you bought don't lay flat when you toss them onto the ground, they never will behave...they will always be spaghetti factory. They're either flexible to begin with or not. Field-use cables are flexible, while most other coax is meant for permanent installation, and is quite rigid. Also, cables with stranded core are much more flexible than solid copper core.

For standard def analog video, the best flexible cable is Canare LV-61S. For SDI, you should look into Belden 1505F (with Canare connectors).

Edited by Kar Wai Ng, 06 December 2009 - 10:03 PM.

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#3 John Sprung

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Posted 07 December 2009 - 12:41 AM

I can't know from a distance how stiff your cables actually are. Cables tend not to change much in that regard over their useful life. If these were designed for permanent installation, there may be nothing to do but use them for that, and get better ones for production.

The other things you need to learn about are over/under and figure eight coiling. These are essential to the handling of any kind of wire or cable on the set, and you pretty much need to learn them in person. Any competent person from sound or electrical can teach you.





-- J.S.
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#4 Chris Keth

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Posted 07 December 2009 - 02:12 AM

If you ever get a crumply small camera cable like lemos and fischers, they can be helped out a bit with a hot hairdryer. You dangle them by one connector and get the insulation good and hot and let it cool off still hanging straight. They'll coil nice and round after that.
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#5 Hal Smith

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Posted 07 December 2009 - 03:00 PM

Arcane Knowledge Warning!

The reason some wires are pliable and others stiff is because of fire resistance. Years ago Susan Clark explained that all to me at an NAB, the more fire resistant the cable, the stiffer. Some stiff cables have thermoplastic insulation which is why the hair dryer gag will work to straighten them out so they coil better.

The best combination of fire resistance and flexibility is rubber, not plastic, covered cables. Unfortunately they're expensive but they do the trick. They also last a lot longer, an occasional wipedown with mineral spirits keeps the rubber looking good. I've got some Belden 8412 mike cables that I know are at least fifty years old and are still very usable. They're on their third (or so) set of XLR's but the cable itself is the original.
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#6 Michael Nelson

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Posted 07 December 2009 - 05:55 PM

Thanks for all of the replies. Where are some other places that sell HDSDI? (say, 50' for my emergency bag)
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#7 John Sprung

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Posted 07 December 2009 - 07:51 PM

Belden now has some plenum rated (fire resistant) stuff that's not as stiff as in the past. It's hard to tell the difference without reading the printing. If you ever find a trade show or other event where Steve Lampen is speaking, go. He's the guru of all things wire and cable.




-- J.S.
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#8 Chris Keth

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Posted 07 December 2009 - 10:17 PM

Belden now has some plenum rated (fire resistant) stuff that's not as stiff as in the past. It's hard to tell the difference without reading the printing. If you ever find a trade show or other event where Steve Lampen is speaking, go. He's the guru of all things wire and cable.




-- J.S.


Sounds edge-of-the-seat exciting. :lol:
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#9 Hal Smith

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Posted 07 December 2009 - 10:49 PM

Sounds edge-of-the-seat exciting. :lol:


I know, I know. Geeks like John and myself get no respect...good cabling is like good focus pulling...no one outside the brotherhood notices until you screw it up.
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#10 Tom Jensen

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Posted 08 December 2009 - 12:02 AM

I know, I know. Geeks like John and myself get no respect...good cabling is like good focus pulling...no one outside the brotherhood notices until you screw it up.


Speaking of which, wouldn't it be easier to just replace the cable with rubber cable as opposed to rigid, hard, stiff unforgiving, unstraightenable, cable?
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#11 Hal Smith

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Posted 08 December 2009 - 07:16 AM

Speaking of which, wouldn't it be easier to just replace the cable with rubber cable as opposed to rigid, hard, stiff unforgiving, unstraightenable, cable?

Canare makes some nice small rubber cables. No multiconductors per se but their mini-quad could be used as four conductor plus common cable.
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#12 Phil Rhodes

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Posted 08 December 2009 - 08:54 AM

Coax will always be stiff; low-capacitance coax as is commonly specified for HD-SDI will be stiffer.

You can, if you're willing to chance it, use more or less any 75-ohm coax for HD-SDI over short runs. The standard white stuff is more flexible than most that's supplied for SDI. Frankly I've never actually had a problem with it even on quite long runs, but your mileage may vary.

P
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#13 Jim Hyslop

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Posted 09 December 2009 - 07:24 PM

The other things you need to learn about are over/under and figure eight coiling. These are essential to the handling of any kind of wire or cable on the set, and you pretty much need to learn them in person. Any competent person from sound or electrical can teach you.

This video demonstrates the technique quite nicely.
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#14 Adrian Sierkowski

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Posted 09 December 2009 - 07:36 PM

I'm a 1/4 hand twist type myself for wrapping; but as mentioned proper wrapping is very important for cable.
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#15 John Sprung

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Posted 09 December 2009 - 08:31 PM

This video demonstrates the technique quite nicely.


Thanks, that's quite good. The one thing I disagree with is plugging the ends of a cable together. Back in my roadie days, this was only done as a quick way of identifying bad cables. The good ones were always tied with the connectors close to the sash cord. Cables mostly fail within about 3" of the connector, and plugging the ends together puts more stress in that area. You'd find the bad ends with an SCR tester, and chop 'em off. Re-solder, and you have a good but slightly shorter cable again.





-- J.S.
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#16 Chris Keth

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Posted 09 December 2009 - 09:23 PM

Thanks, that's quite good. The one thing I disagree with is plugging the ends of a cable together. Back in my roadie days, this was only done as a quick way of identifying bad cables.

-- J.S.


Here they call that "desert wrapping", I assume that's because it helps keep dust and crud out of the female end of the cable.
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#17 Tom Jensen

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Posted 09 December 2009 - 09:41 PM

Thanks, that's quite good. The one thing I disagree with is plugging the ends of a cable together. Back in my roadie days, this was only done as a quick way of identifying bad cables. The good ones were always tied with the connectors close to the sash cord. Cables mostly fail within about 3" of the connector, and plugging the ends together puts more stress in that area. You'd find the bad ends with an SCR tester, and chop 'em off. Re-solder, and you have a good but slightly shorter cable again.
-- J.S.


In my experience, usually it was the connectors that failed.
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#18 John Sprung

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Posted 10 December 2009 - 01:03 AM

In my experience, usually it was the connectors that failed.


Depends if you had the good Cannon connectors, or Switchcrap -- er -- Switchcraft. Performers were sometimes rough on the cable right at the female end, where the microphone plugs in.




-- J.S.
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#19 Tom Jensen

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Posted 10 December 2009 - 10:19 AM

Depends if you had the good Cannon connectors, or Switchcrap -- er -- Switchcraft. Performers were sometimes rough on the cable right at the female end, where the microphone plugs in.
-- J.S.

Audio cables probably take more of a beating than film cables. You don't see a lot of people handling film gear like Roger Daltry or Pete Townshend.
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#20 John Sprung

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Posted 10 December 2009 - 11:13 PM

Here they call that "desert wrapping", I assume that's because it helps keep dust and crud out of the female end of the cable.


Aha -- and the guy who made the video is in Arizona.... Sometimes things make sense.... ;-)





-- J.S.
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