This report examines international frequency management as applied to the 225-400 and 500-890 MHz UHF bands. 40,647 registrations from the 1975 International Frequency List were analyzed in terms of four characteristics: frequency, location, power level, and maximum hours of operation. A relationship between registrations and national interest is suggested, and 10 countries are identified that account for 84.3 percent of registrations in the 225-400 MHz band. Ten countries are also identified that account for 96.4 percent of registrations in the 500-890 MHz band. Seventy percent of transmitters registered in the 225-400 MHz band have power levels of 100 watts or greater, while in the 500-890 MHz band, only 35 percent operate at this level. Intermittent operation dominates the 225-400 MHz band; registrations indicating 24-hour continuous operation dominate the 500-890 MHz band. These findings have implications in terms of potential interference between terrestrial users and current and future Navy SATCOM operations. (Author)