Word: radar
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...panel will also look into a hot dispute about the SRAM-A (for Short- Range Attack Missile), another weapon that would be launched in a nuclear war against the U.S.S.R.: it is carried by bombers on airborne alert and designed to knock out Soviet radar installations, defensive missiles and airfields. The fear is that a fire aboard a bomber could ignite the missile's volatile fuel, which in turn could detonate some of the chemical explosives in its W-69 warhead...
Able to cover a swath of sky from Iceland to the northern coast of South America, the OTH radar can monitor a smuggler's plane from soon after it takes off in, say, Colombia until it reaches the U.S. When a technician in Bangor sees an unscheduled flight over the Caribbean, the information will be relayed - to the Pentagon's Joint Task Force Center in Key West, Fla. An Air Force fighter will follow the suspect plane, and officers of the Customs Service and the Drug Enforcement Administration will be alerted to the mystery craft's course so that they...
...radar operates by sending out radio beams and listening for echoes as the signals bounce back from distant objects. The range of conventional radar is limited by the earth's curvature, since the signal must follow a straight line. Standard ground-based systems work for about 80 km (50 miles), and airborne equipment for 320 km (200 miles). OTH radar gets around the limit by sending beams up to the ionosphere, an atmospheric layer of charged atoms that begins some 75 km (46 miles) above the earth's surface. The signals are reflected by the ionosphere over the horizon, where...
...idea behind this radar is not new; shortwave radio signals have long been bounced off the ionosphere. But developing reliable over-the-horizon radar proved tricky because the composition of the ionosphere is always in flux, making it more like a mass of moving clouds than a smooth reflecting mirror. The OTH radar overcomes this problem by using computer power: the software enables technicians to chart constantly the intensity and thickness of the ionosphere, telling operators where conditions are best and which radio frequencies to use for maximum performance...
...effective, the OTH radar system had to be huge. The signals are sent from three transmitting antennas, each more than 1,095 meters (3,600 ft.) long, in Moscow, Me. Some 175 km (110 miles) away, in Columbia Falls, are three receiving antennas, each stretching nearly 1,520 meters (5,000 ft.). The whole system is controlled by 28 of Digital Equipment Corp.'s powerful VAX computers located at the operations center in Bangor...