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BELL SYSTEM TECHNICAL JOURNAL 



Type 3. The 7-centimeter signal would fade to a low level and remain 

 there for a considerable period of time; sometimes for an hour or so. The 

 character of the fading was unlike that caused by wave interference. The 

 1.25-centimeter signal was simultaneously at a low level and the scanning 

 records showed that only one path was involved. Reception was almost 



60 

 50 

 40 



20 



5 1.0 

 Z OS 



< 



"^0.6 



0.5 



0.3 

 0.2 



0.1 



5 4 3 2 1.5 



WAVELENGTH, A, IN CENTIMETERS 



Fig. 1-5. — Rain attenuation vs. wavelength. 



1.0 



0.8 0.7 0.6 



identical on the two vertically-spaced 7-centimeter antennas. Radar 

 observations suggested that this type of fading was due to attenuation by a 

 reflecting layer in the atmosphere at a height intermediate to the heights of 

 the transmitters and receivers. It was observed, for example, that while 

 the echo from the Murray Hill corner reflector was absent, strong echoes 

 were received from the hill directly in front of Murray Hill and some 250 



