RADIO PROPAGATION FUNDAMENTALS 



595 



the free space field intensity Eo which is given by: 



d 



(2) 



where d is in meters and Pt in watts. 



The use of the field intensity concept is frequently more convenient 

 than the transmission loss concept at freciuencies below about 30 mc, 



130 



O.t — 



-120 



0.2 

 0.3 — 



0.5 



0.7 



01 



111 

 _J 



5 



Z 



10 



< 



z 

 z 



LU 



I- 

 z 

 < 



z 



LU 

 LU 



5 



I- 



UJ 

 CD 



LU 



u 

 z 

 < 



I- 





■110 



Q 

 LU 

 I- 

 < 



< 



cr 

 5 



LU 



z 

 o 



cc 

 o 



LL 



o 



Q. 



-100 



2- 



III 

 5 



5 - 



10 — 



20 — 

 30 — 



50- 



100 — 



200- 

 300- 



500 • 



- 90 



< 



X 



O 

 a. 



LL 



a 



LU 



■80 tu 

 tr- 



LU 

 Q. 



a 

 z 

 o 

 o 



LU 



cr 



UJ 

 D- 



in 



UJ 



_J 

 o 

 > 

 u 

 < 



13 

 UJ 



2 



- 30,000 

 20,000 



- 10,000 



- 7000 



- 5000 



3000 

 ■2000 



- 1000 



- 700 



- 500 



- 300 



- 200 



70 



60 



_l 

 O 

 > 



o 

 cc 

 u 



UJ 



z 

 o 



UJ 



> 



o 



< 



"--hL'OO 



- 70. 



- 50 



30 

 H 20 



160 



— 150 



< 



z 

 z 



UJ 



(- 

 z 

 < 



(J 



D. 



o 

 cc 



I- 

 o 



10 



z 



UJ 



— 140 



a — 



^ r 



10 



■130 



120 



110 



,-100 



50 



5 

 u 



LU 

 Q 



■40 



-90 



- 80 



h 



Fig. 1 — Free space transmission. 



