The report and order of October 26, 1984, amended part 76 to add cable carrier frequency requirements for operation in the aeronautical radio bands. While these new rules provide for universal compatibility with aircraft radio operations and eliminate the need for channel by channel approval, they also present new technical problems for the headend equipment manufacturer and the headend system operator. The newly specified carrier frequencies are offset from the standard assignments but the greatest source of difficulty will be the increased frequency accuracy requirements. In some cases, the rules cannot be met with conventional circuit technology or system design methods.
An assessment of the effect of these rules is presented. The impact on headend product design and specifications is reviewed. Changes in headend system design concepts, operating conditions, channelization strategies and maintenance requirements are discussed. The special case of HRC system operation and the new requirements for reference frequency generators is explained. Finally, consideration is given to the implications for existing headend systems and to possible effects on broadband system and subscriber terminal operation.