the range from 29 to 73 MHz. The Lagrange interpolation formula is 



3 r 3 i 



K=4> L i=4> i k i ' k 

 i*k 



where S(f) is the desired scaling factor for frequency, f, and f, are the 



Evaluation of the parametric equations using the NOSC computer and day- 

 time radio noise power data at 30 thousand feet, p 3Q , and 80 thousand feet, 

 Poq, indicates that for horizontal distances of to 7 miles and altitudes 

 between 5 and 80 thousand feet the equation for noise power in watts per 

 bandwidth, 



P h = p s - A In (h/h ), (14) 



where 



A " ( P 8 " P30»/ ln < h 30/ h 80> (15> 



and 



h - ho e " ((p s~ P 80 )/( P80-P30 ,ln < h 30/ h 80 )J (16) 



gives good agreement to within a few dB of the scaled Seattle data. This is 

 shown on the right side of the graph in figure 6 where the solid line repre- 

 sents the model and crosses indicate Seattle data taken directly over the city 

 and scaled from 1 MHz to 45 MHz. For horizontal distances of greater than 7 

 miles and altitudes from 5 to 80 thousand feet the equation for noi6e power in 

 watts per bandwidth, 



Ph - P s + Bh - Ch 3 , (17) 



where 



B = (P 30 ~ Psl/^O + ch 30 2 (18) 



and 



C " (P 80 ~ P S >/< h 30 2h 80 " ^O 3 ' ~ ( P30 * Ps>/< h 30 3 " h 30 h 80 2) < 19) 



also gives good agreement to within a few dB of the scaled Seattle dats. This 

 is shown on the left side of the graph in figure 6 where again the solid line 

 represents the model and crosses indicate Seattle data taken 50 miles from the 

 city and scaled from 1 MHz to 45 MHz. 



10 



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