Projeot &.3 = Effeots of Atomio Explosions on the Jonosphere - M, Hawn OBJECTIVE Thetegysective of Project 6,3 was to obtain data on the effecta of PINE-. 0200: explosions on the ionosphere, Ws Principally, to <nvesti- gate the area of absorption, probably due to the high altitude radioactive particles, and to study the effect of orientation relative to the earth's magnetic field on F2 layer effects, INSTRUMENTATION The system comprised: Two Ionosphere recoriers, type C-2,cperating on pulse trans- * mission, installed in 6 ton trailer vans, one locate? at Rongerik Atoll and one located at Kusaie in the Caroline Islands, One Yonesphere recorder, type C-3, operating on pulse trans- mission, installed in a C-97 plane based at Eniwetok Island. Detailed Description: Ionosphere recorder site (Rongerik Atoll) site (Kusaie) AN/CPQ-7, type C-2 Tonesphere recorder with a power output of 10 KW peak pulee alternately tranemitting and receiving automatically over the range of frequencies from 1 to 25 megacycles, This equipment measures and records at vertical incidence the virtual height and critical frequencies of fonized regions of the upper atmosphere, A 600 ohm multiple wire antenna designed and erected, so that the direotion of maximum intensity of radiation will be at the ~ 296 um SNL a