School Distributes RF Video on Category 5 Cable
Nov 27, 2001 12:00 PM,
The West Middle School in Wayzata, Minnesota, recently installed aunique new system for distributing RF video on Category 5 cable.Programming for 70 channels is simultaneously distributed to 60classrooms.
Tim Pattrin, the video communication coordinator for WayzataSchools, selected the Category 5 approach because he wanted a systemthat was easy to install and very reliable.
Tim wanted students in a data networking class at Wayzata HighSchool to install the system, so he needed an easy, foolproof methodfor pulling and terminating the cable. Category 5 cable is flexible andeasy to work with, and the students were already trained on the propertermination of RJ-45 connectors.
The Category 5 system is reliable because it uses a homerun wiringsystem and dependable RJ-45 connectors. Each run has only twoconnectors (one on each end), which is much simpler than a coaxial”backbone” system with multiple taps and splitters between the head endand the TVs. In addition, new classrooms can be added to the systemwithout affecting picture quality in classrooms that are alreadyinstalled.
Tim selected a Lynx Broadband system, manufactured by BHElectronics, and installed it in August 2000. Lynx Broadband convertsan unbalanced coaxial signal to a balanced Cat 5 signal, sends it tothe classrooms, and converts it back to a coaxial signal when itreaches the TV. The system uses high performance baluns and filters toconvert the signal and remove any noise or distortion. Because it is apassive system (no power is added) it is inexpensive and veryreliable.
Designing and installing the system was a “hands on learningexperience” for Tim’s high school students. The system combines36 cable channels, 12 broadcast channels, 15 VCR channels, threesatellite channels, two channels with in-house programming, and twochannels reserved for interactive television.
A diagram of the system is shown on the opposite page. Schoolannouncements and other in-house programming can be broadcast live overthe Cat 5 cable system, or sent to a VCR for storage andre-broadcast.
Bi-directional capabilities make it possible to broadcast from oneclassroom to the entire school. A camera and modulator can be rolledinto the classroom, and programming can be sent back through theCategory 5 cable to a sub-band separator at the head end. A processorassigns a new frequency, and the Lynx system distributes theprogramming back out through the system.
Tim rates his satisfaction with the Lynx System as “10 on a scale of10.” The design process was straightforward and the installation workwas quick and easy. All 70 channels have a clear, crisp picture, eventhough some runs are as long as 250 feet.
The high school students who installed the project were pleased withthe results, and the teachers in all 60 classrooms were happy with theclear reception on their televisions. The system has the flexibility togrow as new video technologies emerge, including high definitiondigital television.
The West Middle School is very pleased with their Lynx/Category 5system. They like the ease of installation, the excellent reliabilityand the flexibility for future growth.