156 



A^ CLIMATOLOGY 



100 



90 1^ 



80 



70 





y 60 



-o 50 



LU 

 O 



CO 

 Q 



40 



30 



20 



10 



40 80 120 160 200 240 280 



HEIGHT, h, IN METERS 



Figure 4.48. Distance versus height above dud representing average Washington, D.C., 

 and Fairbanks, Alaska, atmosphere. 



is derived for various transmitter heights and various duct heights. This 

 table is useful in determining the portion of the distance (measured from 

 the transmitter) within the horizon where fading due to the presence of 

 superrefraction has no effect on transmission. 



