Tables 541 (continued) to 545 ^cr 



TABLE 541 (continued). — Absorption Factors for Radio Propagation 



vr c c „ i Damping Nature of Distance Frequency T>_ rrlo ,i, c 



Name of formula factor x path km kc Remarks 



Austin-Cohen 0.0015 °-5 Sea water Up to 2000 80-1000 



Austin revised 0014 .6 Sea water Up to 12000 12-1000 



Fuller 0045 1.4 Sea water 3900 25.4-100 (a) 



E, A, and B 005 1.25 Sea water 5000 17-60 (b) 



(a) Honolulu to San Francisco. 0) Omitted factor Vfl/sin 0, E, A, and B, Espenschied, Anderson and Bailey. 



Bown and Gillet substituting their measured values of F, at 640 kc taken within 150 km 

 of Washington, D. C, in the Austin-Cohen formula get 



a = 0.028 for dry sandy soil; 0.009 Ior moist soil; 0.0025 for yi salt water (Chesapeake 

 Bay). . . . 



Austin concludes that for frequencies greater than 60 kc over land, absorption is con- 

 siderably greater than over sea water. From 60 kc to 20 kc overland absorption decreases 

 and approaches that over sea water. In these results the total field received in the day time 

 is considered. In the following results the ground wave only is considered. 



Over land especially at the higher frequencies there are so many variables that no simple 

 complete formula is available for F. We may write Fxd = a constant from the Hertzian 

 formula and modify it by a factor A for absorption and quote some results, i.e. 



F = (3 77 h//\D)A 

 Smith, Rose, and Barfield calculated from Sommerfeld's theory and approximately checked 

 at some broadcast frequencies the following results. 



TABLE 542. — Transmission Path Over Sea Water Whose Conductivity 

 Was Assumed = 1.1 X IO 11 e.m.u. 



TABLE 543. — Transmission Path Over Land Whose Conductivity 

 Was Assumed = 1.1 X IO 13 e.m.u. 



Rolf calculates from Sommerfeld's theory the following: 



TABLE 544. — Transmission Path Over Land Whose Inductivity e = 15 e.s.u. 

 and Whose Conductivity 8 = 10 13 e.m.u. (Good Conducting Ground) 



TABLE 545. — Transmission Path Over Ground With Inductivity e = 15 e.s.u. 

 and Conductivity a = 10 15 e.m.u. (Bad Conducting Ground) 



Smithsonian Tables 



