The story of a clandestine radio station the CIA set up back in the good old, bad old days of the 1950s, to overthrow Guatemala. The coup succeeded because of the immense power of radio. Or that's what the CIA believed, anyway. We play the recently declassified tapes of the station's broadcasts. We believe it's the first time they've ever been broadcast in this country. Nancy Updike reports. (25 minutes)