572 



AUSTIN: RADIOTELEGRAPHIC TRANSMISSION 



Sommerfeld formula (1) . Column four gives the calculated values 

 as obtained from a semi-empirical formula (2) made up of the 

 first term of the theoretical formula but with the absorption 

 term replaced by the absorption term which was found to be 

 correct in the experiments made in 1910. The values in column 

 fom' are seen to be in very fair agreement with the observed 

 values. 



(2) 



In = 120 TV 



hi hi Is 

 \dR 



■ 0.0015 d 



The Sommerfeld theory takes no account of energy which may 

 be brought to the receiving station by means of reflection or 

 refraction in the upper atmosphere, and it is thought probable 

 that it is this portion of the energy which produces the difference 

 between the observed and theoretical results. 



In connection with these experiments a comparison was also 

 made between the received singals from the Fessenden spark set 

 and those from a Poulsen arc temporarily installed at the Arling- 

 ton station. It was found that, for distances up to about 1000 

 miles, the received antenna currents were practically the same, 

 for the same sending antenna currents. At greater distances 

 the arc seemed to be superior, as measured on the Salem and 

 also at the U. S. Naval Radio Station at Colon, C. Z. 



