B.S.T.J. Briefs: First Result from 15.3-GHz Earth-Space Propagation Study

T H E BELL SYSTEM T E C H N I C A L J O U R N A L , J U L Y - A U G U S T 1970 much less. For example, at the 12-dB level, the data from the diversity pairs separated by seven and nine miles show about a factor of 50 improvement over the individual distributions. The difference between the curves near the bottom of Fig. 1 should not be taken as very significant since the data in those portions of the curves are from only a few rains. The attenuation scale for Fig. 1 is based on T = 273° which is a good fit to 1968 sun tracker data. During the 129 days used for this data sample, 15.26" of rain fell at Crawford Hill. Thus, spacings of from five to ten miles provide considerable diversity advantage on earth-space paths at 16 GHz. The experiment is continuing but the Parkway station has been moved from two miles to twelve miles southeast of Crawford Hill. This will make available diversity data for spacings of seven, twelve and nineteen miles. REFERENCES 1. Wilson, R. W., "Sun Tracker Measurements of Attenuation by Rain at 16 and 30 GHz," B.S.T.J., 48, No. 5 (May-June 1969), pp. 1383-1404. 2. Tillotson, L. C., "A Model of a Domestic Satellite Communication System," B.S.T.J., 47, No. 10 (Dec. 1968), pp. 2111-2137. 3. Penzias, A. A., "First Result from 15.3-GHz Earth-Space Propagation Study," B.S.T.J., this issue, pp. 1242-1245.