USING RADAR FOR WEATHER: The radar systems on the east and west coasts could monitor about 35 million square miles of open ocean, an area few weather instruments could reach. The system had been used to track hurricanes.

ADVANCED TECHNOLOGY: Two Navy high-frequency Relocatable Over-The-Horizon Radars are operated in Texas and Virginia. The radars are most often used for counternarcotics surveillance.

WATCHING RUSSIA: The prototype for the Navy’s system was used to watch the eastern coast of Russia constantly from 1991 to 1993. That radar was on the Aleutian Island of Amchitka, Alaska.