VIET NAM WAR
On two successive nights last June, U.S. F-4 Phantom jets scrambled to intercept what they took to be North Vietnamese helicopters, spotted for the first time crossing the Demilitarized Zone between North and South Viet Nam. The sightings were made by U.S. counter-mortar radar teams atop the hills overlooking the South China Sea. Their radar screens showed blips moving low and slowly, as invading helicopters might if hugging the waves for concealment. Once aloft, the Phantoms soon had moving blips on their own radar screens and unleashed Sparrow rockets at the targets. An eager South Vietnamese officer reported...