Accession Number : AD0644587

Title :   ATMOSPHERIC ATTENUATION MEASUREMENTS AT 600 GHZ.

Descriptive Note : Memo rept.,

Corporate Author : FRANKFORD ARSENAL PHILADELPHIA PA FIRE CONTROL ENGINEERING DIRECTORATE

Personal Author(s) : Chang,Shurman Y. ; Lester,James D.

Report Date : AUG 1966

Pagination or Media Count : 27

Abstract : Atmospheric absorption in the 600 GHz region has been measured throughout the actual atmosphere by means of a Dicke type superheterodyne radiometer receiver using second harmonic mixing. The average measured value of horizontal attenuation was approximately 34 db/km/g/cu m. The variation of water vapor absorption with respect to water vapor density was also indicated in the measured results. The minimum detectable temperature difference (delta T) min was obtained by calculating the rms value of output deflection and the use of the calibration curve for the radiometer. The best value achieved was 5.2K. From this result, the radiometer receiver noise figure and the mixer conversion loss were able to be determined indirectly. The results were 33.2 db and 26.4 db respectively. (Author)

Descriptors :   (*ATMOSPHERES, ATTENUATION), (*SUBMILLIMETER WAVES, ATTENUATION), WAVE PROPAGATION, RADIOMETERS, ABSORPTION, WATER VAPOR, MEASUREMENT

Subject Categories : Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE