6 Reasons To Use Fiber On Your Next Project
Connecting the right cable in the right place is obviously essential for pro AV systems integrators, but choosing the right type of cabling for the job can be just as important. We've all heard the stereotypes, as the fiber versus copper debate has been raging for more than a decade.
In digital video applications, copper cables that are adequate today won't be up to carrying higher-resolution signals that will come with tomorrow's standards, says Steven Barlow, president of DVIGear in Chapel Hill, NC. Future standards for high-definition television will raise bandwidth requirements from 742.5 Mb/s to 1.545 Gb. A 50-foot copper cable could handle the former, but not the latter. Barlow says this is his major reason for recommending fiber to DVIGear customers. “If you want to be sure the pipeline is going to be future-ready, you should consider fiber,” he says.
One technique involved in fiber installations offers added insurance against future needs. It involves installing conduit with space to spare and then blowing in fiber using compressed air. If you need more capacity in the future, you can blow in additional fibers. Commare says this has been done in the Notre Dame Cathedral in Paris to minimize future work in the historic building. Air-blown fiber is also used in the White House, he says.3 Fiber has installation advantages.
Some people think fiber is harder to install than copper. It's true that terminating fiber in the field used to be tricky. “Up until about three years ago, I'll be honest with you, it was a major pain,” Lopinto says. But no more. “Today there are field termination kits where you can put a connector on in three minutes or less.”
That's down from 10 or 15 minutes a few years ago, and is comparable to the amount of time it takes to terminate coax. Meanwhile, fiber is also thinner and lighter than its copper counterpart. “The big disadvantage of having copper cabling is that it's very heavy and very bulky,” says David Caidar, president of Opticomm Corp. in San Diego. Not only does that mean copper cable takes up more space — sometimes a critical issue — but it also makes it more work to install.
Reduced bulk eliminates a number of headaches, especially in rental & staging jobs. A copper snake can be a bulky, intrusive beast that's difficult to route without causing annoyance and hazards to the audience. A fiber snake is much less bulky. “I have many more ways that I can route it and sneak it into places,” Lopinto says.
For those who worry fiber is more fragile and prone to damage, Lopinto disagrees. “Just because optical fiber is made of glass doesn't mean it's easy to break,” he says.
The glass core is well protected, and according to Lopinto, fiber is less sensitive to damage than coax, which can produce ghosting on a video image if the cable is crushed.
Citing a specific example, Commare claims broadcast crews covering professional golf matches have been able to cut four days off their time onsite because of the simplicity of setting up with fiber (see photo, left). “They go from having a bundle of cable that's probably 18 inches to having one bundle of fiber probably as big as your pinky.” And weight is important to broadcasters for another reason — fiber costs a lot less to transport. “They made their money back in the first year just on labor and accommodations and the weight of their trucks,” Commare says.
Installing the cable itself isn't the whole story. With copper cabling, Lopinto says, a series of steps are necessary to ensure a good signal — equalization, gain adjustment, and de-skewing. Fiber requires none of this. “You basically put the product in and that's it,” Lopinto says. “It either works perfectly, or it doesn't work at all.”4 Fiber is immune to electromagnetic interference.
Neither radio-frequency interference (RFI) nor electromagnetic interference (EMI) affects fiber, notes Caidar. This means you can run fiber right alongside electrical cables without worrying about noise. Electric motors, fluorescent light ballasts, and other environmental variables that can cause problems with the signal on a copper cable have no effect on the photons flowing through fiber. That means there are more options for routing fiber. “We have people that run fiber through elevator shafts, which are notorious for being very noisy because of the high-induction motors there,” Lopinto says.