Project 6.3- Effects of Atomic Explosion on the Ionosphere M, A. Hawn OBJECTIVE The objective of Project 6.3 is to obtain data on the effects of high yield nuclear explosions on the Ionosphere. Principally, to investigate the area of absorption, probably due to the high altitude radioactive particles, and to study the effect of orientation re- lative to the earth's magnetic field on F2 layer effects. INSTRUMENTATION The system comprises: 1. 4 Two Ionosphere recorders, type C-2, operating on pulse transmission, installed in 6 ton trailer vans, one located at Rongerik Atoll and one located at Kusaie in the Caroline Islands. 2. One Ionosphere recorder, type C-3, operating on pulse trans- mission, installed in a C-97 plane based at Fniwetok Island. Detailed Description: 1. 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. b. A 600 ohm multiple wire antenna designed and erected, so that the direction of maximum intensity of radiation will be at the “ -72-