INVESTIGATION OF FREQUENCY EFFECTS ON VLF/LF CIRCUITS OPERATING IN NUCLEAR ENVIRONMENTS

RECENT INVESTIGATIONS BY THE DNA NUCLEAR-EFFECTS COMMUNITY HAVE IDENTIFIED VLF/LF LINK TRANSMISSION FREQUENCY AS A SIGNIFICANT PARAMETER INFLUENCING LONGWAVE COMMUNICATIONS EFFECTIVENESS IN MEECN/ WWMCCS APPLICATIONS. THIS PROPOSED PROJECT WILL ADDRESS IN DETAIL THE EFFECTS OF FREQUENCY SELECTION ON SUCH CIRCUITS OPERATING IN PEACETIME AND NUCLEAR ENVIRONMENTS, THROUGH EXPLORATORY DEVELOPMENT OF MODELS TO DEFINE PROPAGATION EFFECTS OVER AREAS OF VARYING GROUND CONDUCTIVITY AND AT VARIOUS DISTANCES. THE INVESTIGATION WILL TREAT GENERALIZED LONGWAVE TRANSMISSION IN THE NORTHERN HEMISPHERE, BUT WILLALSO FOCUS ON EMISSIONS FROM SPECIFIC VLF/LF AIRBORNE TRANSMITTERS OF INTEREST TO THE DEFENSE COMMUNITY. BOTH TE AND TM TRANSMISSIONS WILL BE ANALYZED, AND EFFECTS ON BOTH SIGNALS AND ATMOSPHERIC NOISE LEVELS WILL BE CONSIDERED. UTILIZING PROPAGATION DATA FROM EXISTING DNA LONGWAVE DATABASES, THE INVESTIGATION WILL DEVELOP AND REFINE COMPUTER MODELING TECHNIQUES TO DETERMINE GENERIC FREQUENCY EFFECTS AND WILL APPLY THESE RESULTS TO EXAMPLE CIRCUITS FROM WWMCCS AIRBORNE TRANSMISSIONS. THE PHASE I INVESTIGATION WILL PRODUCE A FINAL REPORT AND RECOMMENDATIONS FOR PHASE II EFFORT, AND AN ILLUSTRATED BRIEFING OF RESULTS.