School Distributes RF Video on Category 5 Cable
Nov 27, 2001 12:00 PM, Gregg Kelley
The West Middle School in Wayzata, Minnesota, recently installed a unique new system for distributing RF video on Category 5 cable. Programming for 70 channels is simultaneously distributed to 60 classrooms.
Tim Pattrin, the video communication coordinator for Wayzata Schools, selected the Category 5 approach because he wanted a system that was easy to install and very reliable.
Tim wanted students in a data networking class at Wayzata High School to install the system, so he needed an easy, foolproof method for pulling and terminating the cable. Category 5 cable is flexible and easy to work with, and the students were already trained on the proper termination of RJ-45 connectors.
The Category 5 system is reliable because it uses a homerun wiring system and dependable RJ-45 connectors. Each run has only two connectors (one on each end), which is much simpler than a coaxial "backbone" system with multiple taps and splitters between the head end and the TVs. In addition, new classrooms can be added to the system without affecting picture quality in classrooms that are already installed.
Tim selected a Lynx Broadband system, manufactured by BH Electronics, and installed it in August 2000. Lynx Broadband converts an unbalanced coaxial signal to a balanced Cat 5 signal, sends it to the classrooms, and converts it back to a coaxial signal when it reaches the TV. The system uses high performance baluns and filters to convert the signal and remove any noise or distortion. Because it is a passive system (no power is added) it is inexpensive and very reliable.
Designing and installing the system was a "hands on learning experience" for Tim’s high school students. The system combines 36 cable channels, 12 broadcast channels, 15 VCR channels, three satellite channels, two channels with in-house programming, and two channels reserved for interactive television.
A diagram of the system is shown on the opposite page. School announcements and other in-house programming can be broadcast live over the Cat 5 cable system, or sent to a VCR for storage and re-broadcast.
Bi-directional capabilities make it possible to broadcast from one classroom to the entire school. A camera and modulator can be rolled into the classroom, and programming can be sent back through the Category 5 cable to a sub-band separator at the head end. A processor assigns a new frequency, and the Lynx system distributes the programming back out through the system.
Tim rates his satisfaction with the Lynx System as "10 on a scale of 10." The design process was straightforward and the installation work was quick and easy. All 70 channels have a clear, crisp picture, even though some runs are as long as 250 feet.
The high school students who installed the project were pleased with the results, and the teachers in all 60 classrooms were happy with the clear reception on their televisions. The system has the flexibility to grow as new video technologies emerge, including high definition digital television.
The West Middle School is very pleased with their Lynx/Category 5 system. They like the ease of installation, the excellent reliability and the flexibility for future growth.
About the author
Gregg Kelley is a product manager for Lynx Broadband Systems. For
additional information, visit www.lynxbroadband.com or e-mail
gkelley@lynxbroadband.com.
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