Table 7 



COST FACTORS FOR AIRBORNE RADAR TECHNIQUES 



Data obtained from Reference 6. 



Does not include additional cost of new radar. 



ionosphere and follows a path that returns to earth at distances of 

 from 500 to 2000 miles from its origin. These characteristics of HF 

 propagation provide the basis for the development of radars that literally 

 "look over the horizon," i.e., OTHR. 



Because HF energy has been used for communications since 

 the earliest days of radio, a well-developed technology exists for the 

 generation, transmission, and reception of HF energy, and the effects 

 of the atmosphere and ionosphere on HF propagation are well understood. 

 Not as well known are the reflection characteristics of material objects 

 at HF and means of concentrating and coding HF transmissions to enhance 



47 



