WILMINGTON, Ohio (AP) — A flip of a switch Wednesday night sput Nike missile bases here and tot Oxford and Felicity, Ohio, and Dillsboro, Ind., into operation and tied them in with the North Amer ican defense network. Lt. Col. Charles R. Arvin, com manding officer of the Fifth Mis sile Battalion, said: “Greater Cincinnati now is com paratively safe from any sneak enemy air attack.” Col. Arvin told Air Force and Army officers, and officials from a Clinton County, that no aggressor snow could get within 500 miles ‘s of the area without being seen on the radar screen and subseqquent is being “killed by one of the Nike missiles. : He said the missiles stored at the four bases are capable of carrying nuclear warheads but he ‘added, ‘I cannot confirm or deny if we have any on the base.” Col. Murray A. Bywater, com mander of the Strategic Air Com mand of nearby Clinton County Air Force Base, said he had re cently witnessed Nike operation ‘l and saw two planes being downed in practice runs. For the first time a civilian audi ence was permitted to enter the “top secret’ plotting room and witness a simulated enemy attack as plotted on a large plastic map of the North American continent. Capt. Marvin H. Gibbs, air de fense operational officer, put on a step-by-step operation ending in the “splash hit’ on an enemy plane north of Cincinnati. Radio and telephone communi cations among pilots and crewmen from the four local bases and from Ft. Knox, Ky., plotted the “enemy” plane every two min utes as it moved toward the local target area at speeds estimated at more than 600 miles an hour. Capt. Gibbs said that when there is an announcement of any heavy movement of an “aggressor” air force, a three-hour alert is put into effect at the Wilmington site. As the situation becomes more seri ous this goes into one-hour, 30 minute, 15 minute and then five minute alerts. As soon as the plane was visually sighted, its position and other data were fed into a computing ma chine. In turn the relative position of the missile was put into the computer. “Within seconds the missile and the plane are infallibly linked so that the end result will be the complete demolition of the plane when the two make contact,” Capt. Gibbs said. The local base has a radar pick up area flanked by Washington, D.C. in the east and St. Louis in the west. To the north is Detroit and south to Chattanooga, Tenn., Capt. Gibbs said,