Broadcast Engineering - February 2009 - (Page 39)

Technology in TransiTion New products & reviews bandwidth of about 6GHz, which is in the middle of the range for broadcast microwave RF applications. Stepping on a cable might seem like a difficult thing to avoid, but if we wouldn’t do it with heliax, it makes no sense to risk precision video cabling. Cables have specifications for pull strength, crush resistance and bend radius that must be carefully followed. It is convenient to pull long runs, but care must be taken to ensure that the installation process maintains the integrity of the original product. One of the most overlooked pitfalls is tying cable in place. Clean installations do not require overly tight cable bundles. Regular and excessively tight cable ties can cause a periodic deformation of the cable, severely compromising the return loss and leading to much shorter working distances before signal degradation. Unfortunately, you might not know the cabling is poorly installed until years later, when the characteristics of the hardware on either end of the pipe changes. This makes a marginally performing cable visible as errors begin to show up in the content that weren’t there at the time of installation. Now, signals can be interconnected over fiber almost as cheaply as over coax when longer runs require equalizing amplifiers in the middle of a pathway. An HD news studio I worked on in 2008 needed amplifiers between weather graphics computers on set and the transmission rack room, where the production switcher electronics were located. Today, installing fiber is not difficult, and an increasing number of manufacturers offer fiber connections. Fiber itself is actually cheaper than copper cabling, though the signal electronics often make fiber less attractive due to the cost of opti- cal to electrical conversion. Wrap-up A few years ago, many people thought that SMPTE 292 (1.485Gb/s) signals on copper were impractical. Today, many think the same of SMPTE 424 (3Gb/s) signals. I expect new technologies for signal equalizers to be shown publicly in 2009 that will move the barrier a bit further out. In the long term, we certainly have arrived at the point where fiber is much more technically practical and affordable. It is easy to install, and in some ways less susceptible to degradation over time than copper cabling in plants with typical broadcast interconnection logistics and distances. BE John Luff is a broadcast technology consultant. ? Send questions and comments to: john.luff@penton.com February 2009 | broadcastengineeringworld.com 39 http://www.neutrik.com http://www.neutrik.com http://www.broadcastengineeringworld.com

Table of Contents Feed for the Digital Edition of Broadcast Engineering - February 2009

Broadcast Engineering - February 2009 Contents Viewing the Slowdown in 3-D Examine Workflows Tapeless Technology Digital Audio 24p and 25p Judder Video Routing: A Look at What's Next Managing AFD The Right Connections Solid State Logic's AWS 900+ SE and More... Advertisers Index

Broadcast Engineering - February 2009

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.