214 REFLECTION AND TRANSMISSION OF RADIO WAVES 



Bm$i^> ■ 



Fig. 4-36 Expanded A-Scope Photographs of Sea Clutter. The Saturated Echo 



in the Center of the Sweep Is from a Stationary Ship. Blanking Gates Near Both 



Ends of the Sweep Define the Base Line. Wavelength, 3.2 cm. 



bined effects of destructive interference below the first lobe and a statistical 

 variation of wave heights. Because of the statistical distribution of wave 

 heights, there are relatively few waves which exceed the average height, 

 and these thus appear as isolated "targets. "-*r^ 



^For a summary of a series of observations of spiky clutter, see F. C. MacDonakl, Charac- 

 teristics of Radar Sea Clutter, Part I: Persistent Target-like Echoes in Sea Clutter, NRL Report 

 4902, March 19, 1957. 



