OVER THE HORIZON VIDEO LINK TO CONNECT SCHOOLS IN A LARGE DISTRICT

THIS PROJECT INVESTIGATES LOW-COST VIDEO LINKING OF RURAL SCHOOLS AND SCHOOL DISTRICTS. RECENT ADVANCES IN TECHNOLOGY SUGGEST THAT THE FORMER MILITARY TECHNOLOGY OF TROPOSCATTER RADIO CAN BE CONVERTED FOR DIGITAL VIDEO TRANSMISSION OVER LONG DISTANCES IN INTERACTIVE CLASSROOM INSTRUCTION AT A SUBSTANTIAL COST-SAVING OVER OTHER TECHNIQUES. TROPOSCATTER COMMUNICATION, WHICH IS CAPABLE OF SINGLE-HOP RANGS OF SEVERAL HUNDRED KILOMETERS, HAS BEEN USED BY THE MILITARY FOR TELECOMMUNICAITON WITHOUT REQUIRING RIGHT-OF-WAY FOR CABLES AND WITHOUT THE ANNOYING ROUND-TRIP DELAY OF SATELLITES. HOWEVER, THE TECHNICAL PROBLEMS OF USING TROPO FOR SENDING COMPRESSED VIDEO HAVE NOT BEEN ADDRESSED. TWO QUESTIONS ARE ADDRESSED: (1) IS THE PICTURE QUALITY ACCEPTABLE FOR INTERACTIVE CLASSROOM APPLICATIONS; AND (2) CAN TROPO RADIOS WHICH ARE PRACTICAL FOR USE IN SCHOOLS BE FIELDED. AN EXPERIMENT IS BEING CONDUCTED USING A STANDARD VIDEO CONFERENCING SYSTEM AND A RECENTLY DEVELOPED HIGH DATA RATE DIGITAL TROPOSCATTER MODEM DESIGNED FOR MILITARY COMMUNICATIONS. A TROPOSCATTER CHANNEL SIMULATOR SIMULATES THE RADIO LINK. THE PRFORMANCE OF THE VIDEO TRANSMISSION OVER REPRESENTATIVE RADIO LINKS IS BEING ANALYZED. TRADEOFFS BETWEEN SYSTEM COMPLEXITY, ANTENNA DESIGN, AND SIGNAL QUALITY TO DETERMINE A MINIMUM COST CONFIGURATION ARE BEING TESTED.