Omega is a very-low-frequency, long-range, hyperbolic radio navigation system under final phases of development. Studies are now being made to determine range capabilities and system stability of the Omega system under actual operating conditions. During October through December 1961, NRL made flights into the Arctic, Temperate and Tropical Regions in a Navy type WV-2 aircraft to monitor signals from experimental transmitters in Hawaii, New York and the Canal Zone. Phase measurements were taken in Greenland, Iceland, Norway and England, and phase and signnal strength measurements were taken in Peru, Chile, Argentina, Brazil and Puerto Rico. These measurements were continuous at each location over a period of 50 to 70 hours and were made with a modified laboratory version of an Omega navigation receiver. The results of these measurements indicate a better than 6000 nautical mile range capability of the system. Diurnal variation in phase during the observation periods was consistent from day to day and predictable on a qualitative basis from geometrical considerations. Position fixing accuracies within plus or minus one mile of the true position will be obtained using transmitters located more than 7000 miles away.