A STUDY OF ' 'PROPAGATION MEDIUM RF NOISE' '.
Abstract
The effects of the propagation medium noise upon long distance, line-of-sight, tropospheric microwave circuits are examined. The propagation medium noise modulates the phase, amplitude, and angle of arrival of the signal. Based upon the limited amount of experimental data available, it is concluded that the phase noise (time frequency noise) will not be serious in the case of transmissions between fixed terminals if the video bandwidth is properly chosen. In particular, frequency components of less than 0.1 cps should be excluded by the video filter. The angle of arrival noise (space frequency noise) may become serious if fixed antennas with beamwidths of less than one degree are used. The amplitude modulation, which is apparently due to some sort of atmospherically modified multipath situation, lead to 25 db fades for a period of time which will be important for high reliability circuits. When one or both of the terminals are moving, the effects of the propagation medium noise should be considerably more serious. Experimental data for this case is extremely limited and numerical estimates are therefore very tentative. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1964
- Accession Number
- AD0433630