- 



COmTOUSS: Fe CdS^hTb) 



Figure 16. Daytime 70 MHz airborne man-made radio noise 

 map of the continental United States for an altitude of 

 30 thousand feet. 



4.4 COMPARISON OF MODEL PREDICTIONS WITH RECENT DATA 



Limited data at the frequency of interest does exist from previous MBCS 

 test flights. Qualitative data from early test flights noted the increase of 

 man-made radio noise with altitude and the existence of radio noise at ranges 

 in excess of 100 miles. This is in agreement with the radio noise model. 

 More recent MBCS data shewn in Table 3 for flights over Ft. Worth and Houston, 

 Texas and several hundred miles out over the Gulf of Mexico, are also in 

 agreement with the model. 



Location 



Time 

 0430 



Altitude 

 7,000 



(Ft) 



Flight Data (FJ 



Model <F A ) 



Ft. Worth 



27 



27 



Houston 



0507 



7,000 





28 



27 



H- -us con 



1141 



16,000 





33 



32 



Gujf 



0617 



29,000 





15-19 



16 



Table 3. 45 MHz airborne man-made radio noise, 

 MBCS flight data and model comparison. 



18 



