THE RADIO ROOM ============== Several receivers sit beneath a dead wall clock. Most produce ordinary static. One receives a continuous low carrier. Another periodically says one word: NINETEEN. A third receives Wisconsin AM radio from 1986: weather, farm prices, traffic and a song that ends before its first chorus. The broadcast is not a ghost in any useful technical sense. It may be memory, echo or time behaving badly. The low carrier has three tones hidden inside it.