PENA NEGRA ARMY BASE, Colombia — On a craggy perch 13,000 feet above sea level, 43 soldiers spend their days peeling potatoes, watching sappy soap operas and trying to insulate their flimsy barracks from roaring winds and fierce cold. Their job, ostensibly, is to protect a radio tower and mainframe communications equipment from anti-government guerrillas who have been waging war since the 1960s.