aa, fi D‘dele (OSAGE) - Project 6.6 -— Electromagnetic Attenuation Measurements - T. D. Hanscome OBIECTIVE To make electromagnetic attenuation measurements as a function of time at S-band (2160 MC) and X-band (9400 MC). PROCEDURE Installation on Runit (Yvonne) consisted of the repaired QD (Blackfoot) installation (3590 feet from GZ) plus a transmitter and antenna on top of the bunker at ground zero. Both transmitters were cn a line to the receiver in a tower on Parry, used to measure attenuation. Both receivers were The transmitter frequencies were separated enough to prevent image interference. Each receiver output was dis- playei on scopes with scope sweep speeds of 5 microseconds per centimeter anj 100 microseconds per centimeter. In adiition the Brush re- corjer was used on the receiver tuned to the transmitter at ground zero. RUSULTS All equipment operated successfully. transmitter complete and detailed. The record from the 3500! It confirms and extends the re- sults of cho Wall Abe (Blackfoot), The delay introduced in the received signal in order to show the transmitted signal level existing two microseconds before time zero was not sufficient for the signal from the ground zero station. How- ever, the recovery rate can be observed, and by the end of one millisecond the signal had recovered to within 20 db of full signal strength. Island power was turned off before signal recovery could show up in the Prush recorder, . COPIED é LAN eed ~19-