WHITE PAPER Fiber in Broadcast and Production Facilities Ten Things Every Professional Should Know For years, television broadcasters have relied on coax cable to route video and audio control signals and RF around their facilities. Coax has proven itself to be easy to work with and reliable. However, as the television broadcast business evolves from a single analog channel to a digital world, the industry is re-evaluating the role of coax. In its place, fiber- optic cable is emerging as a logical solution for next-generation television signal routing, where greater bandwidth is needed to accommodate HD signals and multicast SD channels. As these applications drive fiber into more networks every day, many broadcasters’ deployment strategies overlook one major consideration. Good cable management practices are the key to an effective fiber network, allowing for flexibility, fluid change, easier network maintenance and configuration and, most importantly, growth. When a broadcaster uses good cable management from the start in its fiber network , the network grows more quickly. Good cable management practices also ensure that the fiber networks of today will be ready for the higher- bandwidth applications of tomorrow. This paper explores the top ten things you need to know about fiber; things you should understand when planning for an upgrade that includes fiber. Topics covered in this paper are: T opic Page # 1. Key Fiber Cable Management Concepts 3 2. Making Connections 4 3. Singlemode versus Multimode 5 4. Angled versus Ultra Physical Contact Connectors 6 5. Connector Styles 7 6. Field vs. Factory Terminations 8 7. Splicing vs. Field Connectors 9 8. Slack Storage 10 9. Fiber Density 11 10. Planning for Future Growth 12 Fiber for Broadcast and Entertainment Professionals Top Ten Things to Know Top Ten Things to Know Page 3 For years, broadcasters have relied on coax cable to route video, audio and control signals and RF around their facilities. Coax has proven itself to be relatively easy to work with and reliable. However, as the broadcast business evolves from a single analog channel to a digital broadcast world, the continued roll of coax cable is being re-evaluated. In its place, fiber optic cable is emerging as a logical solution for next generation signal routing, where greater bandwidth is needed to accommodate HD signals and multicast SD channels. Unfortunately, the knowledge that broadcast engineers have gained about working with coax cable isn’t particularly transferable to using fiber. New issues, such as signal attenuation or complete loss from severe bending, proper troughing, crush load tolerance, and cable density and accessibility, must be considered when managing a fiber optic network. Proper cable management practices make fiber networks less susceptible to accidental damage, quicker to install, less expensive to own and operate over the long haul and easier to expand as needs grow. Key cable management concepts include: • Bend radius: At turns in fiber runs, maintain a 1.5-inch bend radius. Tighter bends may cause micro-bending of individual fibers that allow light to escape the signal path, resulting in signal attenuation. More severe bends can break fiber strands completely, resulting in signal loss. • Cable troughing: Used to route fiber optic cable, troughing systems provide a protected pathway for fiber to traverse spans between rooms and equipment racks. Good troughing systems will keep fiber separate from coax cable, protect it from out-of-tolerance bends and promote neat, easily accessible runs. • Vertical cable protection: Allowing fiber to hang unprotected from the back of equipment can be a recipe for disaster. Exposed cables are easy to snag accidentally with a hand or foot, which can result in damage to the connector or fiber itself. Additionally, over time the weight of hanging fiber can cause bends outside the acceptable limit and consequential damage to the fiber. Proper vertical cable management in panels or equipment bays provides adequate support, cable protection and a transition from the vertical run to the back of the equipment that does not damage the fiber. • Cable pile-up: In horizontal fiber runs, it is unacceptable to allow a pile of fiber cable to exceed two inches. Beyond that point, the weight of the bundle will surpass the crush tolerance limit of the fiber at the bottom of the stack, resulting in microscopic damage and signal attenuation. • Cable segregation: Keep fiber runs separate from legacy coax cable. Coax is relatively heavy and can crush fiber cables. Additionally, segregating coax from fiber ensures that technicians repairing coax do not accidentally damage the fiber cable while working on the copper. • Labeling: Develop good labeling practices. Know where fibers originate and terminate. Doing so will reduce maintenance time and the likelihood that a maintenance tech will make hasty decisions on fiber routing that can lead to a rat’s nest of cable and patch cords. • Density: When selecting products for a fiber network, remember future maintenance. The more densely connectors are packed onto a panel, the more difficult it will be for even the most dexterous technicians to maintain. Remember, inevitably cables will be moved, so the ability to trace and re-route them is critical to working efficiently. • Future proofing: When planning rack configurations with a given number of terminations to accommodate a relatively low number of fibers for today’s requirements, don’t forget the future. A fiber path that easily supports 12 fibers today may be inadequate to support the 200 fibers needed in a few years. Planning up front for the future can save the expense of ripping out outgrown capacity down the road. Proper cable management is extremely important to the successful conversion of broadcasters from coax to fiber. The fact that a single fiber may transmit mission-critical signals, such as revenue-generating commercials and programming, underlies the importance of taking the steps necessary to manage fiber’s installation and use. Point at Which Light is Lost From Fiber Optical Fiber Light Pulse Macrobend Area in Which Light is Lost From Fiber Optical Fiber Light Pulse Radius of Curvature 1) Key Fiber Cable Management Concepts Microbend Integrating fiber into a broadcast facility requires a logical means of connecting various devices throughout the facility for production, playback and post-production tasks, not unlike what has been done for years with coax cable, patch panels and routing switchers. On the most basic level, there are three approaches to network architecture: • Direct connect: This approach is straightforward, but exceedingly limited. The output of one device is connected to the input of another. While the least costly of the three, it is inflexible and requires manually moving cables at potentially far-flung source and destination points in order for them to be reconfigured. This approach has limited usefulness in broadcast applications. • Interconnect: This architecture relies on a passive patch panel to act as an intermediate point where fiber from devices like tape machines and still stores can be connected. While eliminating the need to hike to remote equipment locations to remove a cable from one device so that it can be reconnected to another, the interconnect architecture isn’t without its downside. The lack of circuit access makes remote monitoring, testing and patching impossible. • Cross-connect: With a centralized cross-connect patching system, achieving the dual requirements of lower costs and highly reliable service is possible. In this simplified architecture, all network elements have permanent equipment cable connections that are terminated once and never handled again. Technicians isolate elements, connect new elements, route around problems, and perform maintenance and other functions using semi-permanent patch cord connections on the front of a cross-connect system. Here are a few key advantages provided by a well-designed cross-connect system: • Lower operating costs: Compared to the other approaches, cross-connect greatly reduces the time it takes for adding cards, moving circuits, upgrading software, and performing maintenance. Because all changes are made at one convenient location, technicians are able to quickly and accurately perform their work. • Improved reliability and availability: Permanent connections protect equipment cables from daily activity that can damage them. Moves, adds, and changes are effected on the patching field instead of on the backplanes of sensitive routing and switching equipment, enabling changes in the network without disrupting service. With the ability to isolate network segments for troubleshooting and reroute circuits through simple patching, technicians can perform maintenance without service downtime during regular hours instead of during night or weekend shifts. These three approaches to fiber network design and signal routing offer an ascending ladder of flexibility, convenience and control. On the bottom rung is direct connection between devices. For broadcast applications, this configuration is not recommended. The interconnect architecture is most practical approach when there is limited rerouting of inputs and outputs and circuit access is not important. The cross-connect architecture stands at the top of the ladder, providing the flexibility and reliability broadcasters need in signal routing. Top Ten Things to Know Page 4 2) Making Connections: Direct, Interconnect and Cross-Connect Approaches Direct Connect Cross-Connect Interconnect Top Ten Things to Know Page 5 As the broadcast industry makes its transition from analog service to Digital TV, broadcasters are being asked to address issues they hadn’t considered even a few years ago. What’s the right mix of multicast DTV channels? Should HD programming be originated locally or should SD be upconverted? What sort of DTV transmission scheme is appropriate? Will distributed transmission solve coverage problems and if so, how will STLs to multiple digital transmitter sites best be accomplished? With each new question comes a growing recognition that the existing plant must be upgraded or in extreme cases replaced entirely to answer the demands of broadcasting in a digital world. As broadcast engineers grapple with these questions, the need has never been greater to route more signals between more devices with greater bandwidth. Whether it’s HD studio cameras, multiple STL links or distribution of wide band signals throughout the station, fiber optic cable offers an affordable alternative to copper coax cable. Additionally, its greater bandwidth capacity future- proofs installations as increased bandwidth demands are more easily accommodated than with copper. Fiber optic cable comes in two varieties: singlemode and multimode. Both have applications for broadcasters. Singlemode fiber optic cables transmit a single ray of light used to carry modulated signals. It is normally used in applications requiring the transmission of signals over a long distance. In the broadcast industry, singlemode fiber is well-suited for applications such as studio-to- transmitter links, camera control units and runs from a studio to satellite earth stations or to cable headends, or between separate facilities on a broadcast campus. Multimode fiber optic cable carries multiple light rays with different reflection angles within the fiber core. With a fiber core that’s thicker than singlemode fiber, multimode cable is better suited for short runs, such as those between equipment and panels in broadcast facilities. Multimode may be used to feed routers, servers, editing stations and video servers. Replacing copper with fiber is no longer economically impractical at broadcast facilities. Once regarded as expensive, the proliferation of fiber for business LANs and WANs and its use in telecommunications networks has brought an economy of scale to bear for fiber cable, connectors and components that can benefit broadcasters. A recent study comparing the costs of first-time installations of fiber with copper (CAT5, CAT5e and CAT6) found that an “all-fiber solution offered a lower total initial cost than the UTP-fiber network” for 12 scenarios that were studied. According to the study, conducted by Pearson Technologies Inc. and the Fiber Optics LAN Section of the Telecommunications Industry Association, “In many cases deploying multimode fiber cable throughout the network is significantly less expensive than installing new grades of UTP copper cable.” These new marketplace realities could not have been timed any better for broadcasters grappling with how to modernize their facilities for the demands of DTV in a cost-effective way. Fiber offers other benefits broadcasters will find attractive. On a physical level, it requires far less space than coax. Fiber connectors are also physically smaller than their coax counterparts. Additionally, fiber optic cable offers broadcasters a level of security that exceeds copper or microwave transmission because it is difficult to tap without breaking. 3) Singlemode versus Multimode Fiber Fiber Applications in a Broadcast Family Attaching a connector to a fiber optic cable will cause some of the light traversing that fiber to be lost. Regardless of whether the connector was installed in the factory or the field, its presence will be responsible for some light being reflected back towards its source, the laser. Commonly known as return loss (RL), these reflections can damage the laser and degrade the performance of the signal. The degree of signal degradation caused by RL depends on the specs of the laser; some lasers are more sensitive to RL than others. Different types of applications tolerate different degrees of RL too. The experience of the cable television industry has shown video equipment only tolerates a minimal level of optical return loss. Similarly, high bandwidth broadcast applications (such as uncompressed HD) and long haul links between studios and transmitter sites require minimal RL. The amount of optical return loss generated is related to the type of polish that is used on the connector. The “angled physical contact” (APC) connector is best for high bandwidth applications and long haul links since it offers the lowest return loss characteristics of connectors currently available. In an APC connector, the endface of a termination is polished precisely at an 8-degree angle to the fiber cladding so that most RL is reflected into the cladding where it cannot interfere with the transmitted signal or damage the laser source. As a result, APC connectors offer a superior RL performance of -65 dB. For nearly every application, APC connectors offer the optical return loss performance that broadcasters require to maintain optimum signal integrity. However, it is extremely difficult to field terminate an angled physical contact connector at 8 degrees with any consistent level of success. Therefore, if an APC connector is damaged in the field it should be replaced with a factory terminated APC connector. The “ultra physical contact” (UPC) connector—while not offering the superior optical return loss performance of an APC connector—has RL characteristics that are acceptable for intraplant serial digital video or data transmissions. When using UPC connectors, make sure your laser’s specs can handle the return loss your UPC connectors will generate. Offering –57 dB RL, ultra physical contact connectors rely on machine polishing to deliver their low optical return loss characteristics. Ultra physical contact polishing refers to the radius of the endface polishing administered to the ferrule, the precision tube used to hold a fiber in place for alignment. The rounded finish created during the polishing process allows fibers to touch on a high point near the fiber core where light travels. Unlike APC connectors, UPC connectors can, with the proper tools and training, be repaired in the field. Top Ten Things to Know Fiber Casing Fiber Core 8° Angled Endface Ø 2 Ø 1 Ø 3 Ø 3 > Critical angle defined by Snells Law Ø 1 =Ø 2 Light is reflected into cladding along Ø 3 n 1 n 2 Fiber Casing Fiber Core polishing creates a rounded finish 4) Ultra Physical Contact Connectors and Angled Physical Contact Connectors Angled Physical Contact (APC) Ultra Physical Contact (UPC) Top Ten Things to Know Several fiber connector styles are popular today, including SC, ST ® , FC, Duplex SC, LC, LX.5 ® , MTRJ, and MTP, but some are more appropriate for use at broadcast facilities than others. Of the traditional singlemode and multimode connectors, FC, SC, LC, and LX.5 are the only ones that can be “angled physical contact” (APC) polished. FC, SC, LC, LX.5 and ST can be polished using the “ultra physical contact” (UPC) method. Newer, small-form-factor connectors, such as the LC and LX.5, also are appropriate for broadcast applications requiring density on patch panels. As discussed previously, in an APC polished connector the endface of a termination is factory-cut precisely at an 8-degree angle to the fiber cladding. This design reflects most of the return loss (RL) to the cladding, not all back to the source. As a result, APC is ideal for high- bandwidth and long distance broadcast applications. In an ultra physical contact connector, machine polishing creates a rounded finish to the fibers being connected so that they touch on their high points. While the RL specs for UPC are not as good as APC, they are fine for serial digital video and intraplant optical transmissions. The types of fiber connectors appropriate for broadcast applications include: • SC – “Sam Charlie” or “Snap Click”: The most popular of all connectors, the SC style offers excellent loss characteristics and comes in a standard footprint. It is easy to snap in and remove. The SC is pull-proof and is available in UPC and APC styles. • FC – “Frank Charlie”: One of the most popular connector styles, the FC offers excellent loss characteristics and comes in a standard footprint. The FC inserts by twisting a threaded connection with key alignment. It is pull-proof, being difficult to remove. Made from metal components it is available in UPC and APC styles. •ST ® – “Sam Tom”: Very similar in appearance to a BNC connector, the ST is a screw-on type connector. It does not offer the pull-proof resiliency of SC and FC connectors. ST connectors, which are made of metal components, are only available with UPC polishing. In recent years, the popularity of ST connectors has waned as the use of SC and FC connectors has grown. • Duplex SC: Offers the same features as the SC style but supports two-way communication. • LX.5 ® : Exactly half the size of an SC connector, the LX.5 offers twice the density of its larger counterpart. Key to the LX.5 is its use of safety shutters on both the connector and the adapter body to provide protection from dust, dirt and damage from ferrule endface handling. Available in UPC and APC. • LC: The LC comes in a small-form-factor that competes with the LX.5. The LC features are similar to SC, but its size allows double the density. Available in UPC and APC. When designing a fiber network for routing signals through a broadcast facility, standardizing on a single connector type will make network repairs and technician training faster and less expensive. However, despite efforts to standardize on a single connector style, it may be necessary to use a hybrid cable to move the set standard. Adopting the LC or LX.5 style connector makes sense in a broadcast facility because of the sheer number of sources and destinations common at stations and the use of multicore fiber to route signals between them. The smaller size of the LC and the LX.5 connector means more individual strands of multicore fiber can be broken out, connectorized and accommodated on a patch panel. As long as the panel is designed ergonomically so that technicians and engineers can actually grasp a patch cord connector connected to a densely-packed panel, this application of LC and LX.5 connectors is sound. If the panel is packed too densely, there is always the option of breaking out individual fibers of a multicore run to larger, easier-to-grasp SC connectors. Ease of use and protection against fibers being accidentally pulled is more important in broadcast facilities, as fiber panels are typically installed in high- traffic areas. 6) Connector Styles Broadcast engineers who cut their technical teeth attaching connectors to coax cable might be surprised to learn that when working with fiber, relying on factory-terminated cables offers several advantages over field termination, including performance and savings in labor, material costs and installation time. Unlike field-terminated fiber, preconnectorized cable assemblies are guaranteed to work out of the box to the highest performance specification. Under the best circumstances, field-terminated cables offer 0.5 to 0.25 dB signal loss, while factory-terminated fiber delivers typical loss of less than 0.2 dB. Factory termination will provide consistent loss values, making network planning more accurate. Engineers who have worked hard over the past several years to implement video production workflow solutions that improve productivity have personal knowledge of the ongoing efforts at stations to work as efficiently as possible and to use labor wisely. Against this backdrop, using factory-terminated fiber in stations makes a lot of sense. The labor savings associated with using factory- terminated cables in most instances make it a more economical solution than field termination of fiber cables. Not only do factory-terminated cables eliminate the labor costs associated with installing connectors in the field, they also do away with the need to spend money on re-doing work that has failed as well as the cost of additional connectors. Factory-terminated cable comes from the manufacturer where it was prepared under the supervision of fiber optic experts in an environmentally controlled setting with quality inspection and testing. Connectors are attached to individual strands of fiber in an automated factory process that is not as subject to human error. Once attached to the fiber cable, the connections are tested to ensure quality and performance. When fiber is terminated in the field, bulk cable arrives at the broadcast facility on optical cable reels with packages of connectors. That cable must be pulled between points and attached to patch panels at both ends of each run. Before it can be attached to the panel, technicians must attach connectors to each strand of fiber. Those field-terminated connectors, which get plugged into the back of patch panels, can fail or perform below acceptable signal loss tolerances. Relying on factory-terminated cable requires some forethought and planning. Knowing where panels must be located and the length of runs from the panel to various pieces of equipment is necessary, but it’s also important to know how best to bring panel, fiber and equipment together. One approach is using multifiber cable with factory-terminated connectors attached to one end for the equipment side of the run. At the patch panel, a factory-connectorized pigtail plugs into the back of the panel leaving a factory-prepared stub end ready for splicing. Station technicians then splice individual strands of the multifiber cable to single strands of fiber making up the pigtail. The other approach is similar. Here factory-connectorized pigtails are used on both the equipment and the patch panel ends of the run. Broadcast technicians then splice individual strands of fiber (see the next section on splicing to learn more) in the multifiber cable between both ends to individual fibers in both pigtails. For broadcast engineers who have grown up in the business cutting coax to length and attaching connectors, these approaches might seem a little foreign. However, the clear advantages of lower labor costs, higher performance and the elimination of wasted material and time offered by using factory-terminated fiber optic cable make a little re-orientation in engineering mindset and practice more than worthwhile. Top Ten Things to Know Page 8 6) Field versus Factory Connector Termination Top Ten Things to Know Page 9 Common practice among broadcast engineers calls for cutting coax to the desired length and attaching connectors in the field. Doing so with coax is fast, easy, and results in precise control over cable length. However, that isn’t always the best solution for fiber, especially when cable runs are longer than 25 meters, singlemode fiber is being used, or a degree of permanency is required. For those situations, splicing individual fibers as shown in figure 1 offers an attractive alternative. Among the benefits of splicing fiber are lower signal loss, more predictable results and the faster speed at which it can be done by a trained technician. Fusion splicing of fiber in the field offers substantially greater efficiencies in time and performance than attaching connectors. Fusion splicing fibers is done by the following process: • Outer jacket removed from multicore cables and broken out to individual 900 micron cables and strength member or yarn trimmed • Individual fibers are stripped to 250 micron bare fiber • Fiber cleaved, resulting in a flush end • Fiber prepared for splicing by cleaning the ends and putting a shrink tube over one end • Both cables put into the alignment device on the splicing equipment, which will align the fiber ends • Laser fusion procedure initiated on the equipment • Technician removes the fusion splice and visually inspects the junction with a high powered microscope (typically part of the splicing equipment kit) • Fusion splice secured into the splice holder on the fiber panel splice tray Trained technicians can splice two strands of fiber together in as little as 5 minutes, which compares to 15 minutes per field-terminated connector. The efficiency of splicing becomes even more pronounced when comparing splicing a 24 fiber cable to field terminating it – 2 hours vs. 12 hours. The difficulty of adding connectors in the field also means that the yield of acceptable connections will be directly related to the skill level and experience of the technician. Unlike fusion splicing, there is no automatic labor savings associated with field terminating connectors and testing connections. Anecdotal experience indicates that as many as 50 percent of field-installed connectors fail when done by green technicians, resulting in time- consuming, costly do-overs. In terms of performance, field-terminated singlemode connectors can leave engineers wanting. Under the best circumstances, they offer 0.25 dB signal loss, while loss from fusion splicing typically is 0.01 dB. Splicing is most appropriate for long runs of fiber between buildings or separate floors of the same building and is best-suited for applications where connections are intended to be permanent. It provides the best solution for connecting points separated by an unknown distance. Conversely, preterminated connectors or field termination, as shown in figure 2, is a better solution for short runs of multimode fiber. Field-terminated connectors make the most sense for multimode fiber between two points separated by a known distance. 7) Splicing vs. Field Connectorization Figure 1: Splicing at both panels is most appropriate for long runs of singlemode fiber where distances are unknown and connections are intended to be permanent. Figure 2: Field terminated connectors are a good solution for short runs of multimode fiber between points seperated by a known distance. Unmanaged patch cord slack is a silent threat to mission- critical operations at broadcast facilities using fiber optic cable to route signals around the facility. A misplaced foot or wandering hand can accidentally snag exposed loops of fiber patch cord and pull it with enough force to damage optical fibers and harm connectors. More importantly, untended patch cord slack that gets yanked might be carrying a commercial to air, requiring expensive make-goods, or interrupt an edit session for an important client. In either case, the resulting harm could be far greater than cost of a little prevention. Broadcast engineers planning an upgrade or system change-over to fiber optic cable should include storage of slack patch cords in their plans from the outset. Besides the ability of proper slack management to tidy up the look of a facility, it also elevates the confidence level of station engineers as they work in equipment racks free from the fear that a false move might accidentally do harm. Another important benefit of having a dedicated slack storage system for patch cords is the ability to specify a single patch cord length for the entire plant. Proper slack storage means that a 5-meter patch cord can be used for a long or short patch without fear that dangling excess fiber will be damaged. Stations entwined in a rat’s nest of patch cords can improve the appearance of their rack areas and make patching much simpler with proper slack storage. Systems that store patch cord slack properly maintain a minimum bend radius of 1.5 inches to protect against damage to fiber. They also provide easy access for convenience when it’s necessary to reconfigure a patch. From integral storage compartments in stand-alone termination cabinets to 19-inch 1RU fiber management trays, slack storage systems can take many shapes. But the common thread among all of these systems is that extra patch cord lengths are neatly stored, protected from damage and aren’t exposed to accidents that can negatively impact the ability of a facility to earn revenue. Top Ten Things to Know Page 10 8) Slack Storage: Protecting and Managing Fiber Cables Bulk/Storage Drawer Fiber Storage Tray Panel Interbay Management Panel [...]... planning that addresses all key issues including proper cable management The fact that a single fiber may transmit missioncritical signals, such as revenue-generating commercials and programming, underscores the importance of taking the steps necessary to manage fiber s installation and use Web Site: www .adc. com From North America, Call Toll Free: 1-8 0 0-3 6 6-3 891 • Outside of North America: + 1-9 5 2-9 3 8-8 080... you to scale efficiently 10) Planning for Future Growth Broadcast engineers who plan to add fiber to an existing coax plant or to build a fiber- based facility from scratch should not ignore the demands for system growth that they inevitably will face What today seems like abundant capacity in a network with 24 or even 12 fibers will seem paltry, over-taxed and inadequate in a few years One only needs... of North America: + 1-9 5 2-9 3 8-8 080 Fax: + 1-9 5 2-9 1 7-3 237 • For a listing of ADC s global sales office locations, please refer to our web site ADC Telecommunications, Inc., P.O Box 1101 , Minneapolis, Minnesota USA 5544 0-1 101 Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications... a good thing because there’s more to consider than simply how much rack space will be used Broadcast engineers walk a fine line trying to balance their desire to maximize rack space and eliminate the coax clutter, with the practicality of maintaining densely packed connectors and cables What price must be paid to maximize rack space? Will densely packed connector panels make it more timeconsuming to... protection and providing for expanding slack storage needs will minimize the possibility that an initial fiber cable installation will be damaged and allow the fiber network to grow more easily and quickly Plans for future growth should take today’s typical broadcast network topology into account as well as make provisions for centralized operations tomorrow As it’s envisioned and being implemented, three... is possible to have half-full racks, that lack cable management features, so tightly packed with cables and connectors that new fiber panels cannot be added In that case, the only alternative is to rip out the existing rack and start from scratch—a real waste of the initial outlay The best way to avoid this potential problems is to invest in fiber infrastructure that has built -in cable management features... drives in personal computers that “never” would be filled to understand how demand quickly catches up with and surpasses capacity WHITE PAPER When building a fiber network, it is essential that future growth is considered and good cable management practices employed Practices such as following a 1.5-inch bend radius policy, guarding against excessive cable pile-up, troughing horizontal runs, implementing... product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents Products or features contained herein may be covered by one or more U.S or foreign patents An Equal Opportunity Employer 1305075 10/ 04 Original © 2004 ADC Telecommunications, Inc All Rights Reserved ... be mindful of the prospect of centralized operations in the future and the demands it will place on existing fiber and the need to grow Conclusion As the broadcast industry evolves fiber is more frequently being deployed as the preferred medium for high bandwidth applications like HDTV Proper cable management is critically important as fiber upgrades are made The successful conversion from coax to fiber. .. force fiber into sharp bends that could damage the fiber core and attenuate the signal More cable also means an increased tendency to overlook recommended cable pile-up tolerance and adequate slack storage practices Additionally, densely-packed connectors can make it impossible for a technician to access a single fiber as opposed to all of them at once Ironically, when it comes time to expand the installation, . concepts include: • Bend radius: At turns in fiber runs, maintain a 1.5-inch bend radius. Tighter bends may cause micro-bending of individual fibers that. tools and training, be repaired in the field. Top Ten Things to Know Fiber Casing Fiber Core 8° Angled Endface Ø 2 Ø 1 Ø 3 Ø 3 > Critical angle defined by