cma MEEct) Project 6,3 - Effects of Atomic Explosions on the Ionosphere - M, Hawn OBJECTIVE The objective of Project 6,3 was to obtain data on the effects of high yield nuclear explosions on the ionosphere, Principally, to investi- gate the area of absorption, probably due to the high altitude radio- active 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 recorders, type C-2, operating on pulse trans- mission, installed in 6 ton trailer vans, one located at Rongerik Atoll and one located at Kusaie in the Caroline Islands, One Ionosphere recorder, type C-3, operating on pulse transmission, 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 Ionosphere recorder with a power output of 10 KW peak pulse alternately transmitting 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 ionized regions of the upper atmosphere, A 600 ohm multiple wire antenna designed and erected, so that the direction of maximum intensity of radiation will be at the come CIE VB “ a us | xq - 29 -

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