-* —_ True to forecast, BRAVO Day was poor for radio propagation. QRN and QRM bothered all voice and radio-teletype circuits, but on the whole, communications continuity was maintained. Within three hours after the blast, the Command Ship (USS ESTES) was washing down every- thing above decks. Since this included antennae, this raised havoc with voice and radio-teletype circuits on the ship. In addition, some indications, especially from Task Group 7.2's long-haul circuits, pointed to jonospheric disturbances due to the blast. However, air= craft control circuits, both voice point-to-point and air-to-ground, maintained continuity. Some improvisation was necessary; the VHF relay circuit remained active and the control destroyer acted as a voice re- ; lay for circuits J-407 and J~408. The most significant observation of the Combat Information Center (CIC) during the BRAVO Shot was that the detonation did not seriously affect either radar or radio transmissions. This observation was in direct contrast to that made during MIKE Shot in Operation IVY, when both radar and radio seemed to be seriously affected bythe explosion. Weather seemed to be the deciding factor. During MIKE Shot, the air was heavily saturated with visible moisture prior to the shot. BRAVO it was not. During MIKE Shot generated numerous cimulo-nimbus type clouds reaching to extremely high altitudes, but BRAVO did not. Radar scopes were cluttered for several hours with widespread cloud returns during MIKE, making sampling aircraft control extremely difficult. scope was clear thirty minutes after BRAVO. The IFF returns and radar blips disappeared for brief intervals during BRAVO, although no clouds were visible on the scope. aFWLHc This made for good control of all aircraft. NS