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Radio Science

ATS-6 ascending: Near horizon measurements over water at 30 GHz


  • W. J. Vogel,

  • A. W. Straiton,

  • B. M. Fannin


The return of the ATS-6 satellite to a western longitude during the fall of 1976 presented a unique opportunity to perform low-angle-of-elevation measurements at 30 GHz. For this purpose a receiver using a 1.5 m antenna was set up at Port Aransas, Texas, resulting in a propagation path entirely over water. The 30 GHz beacon was monitored daily for at least one hour from 8 September to 21 September 1976. During the time the elevation angle changed from 1.5° to 17.3°, the mean attenuation decreased from 20 to 2 dB and the standard deviation from over 6 dB to less than .2 dB. The deep fades at angles below 4° show significantly sharper nulls than peaks on a log scale. Spectra of the log amplitude fluctuations vary as the (−8/3) power of the spectral frequency in the limit. A flattening is noticeable at the low frequencies. A precipitation event at 8.5° elevation produced a 16 dB fade and significantly increased the variance.

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