JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. 9 AUGUST 19, 1919 No. 14 



RADIOTELEGRAPHY. — Calculation of antenna capacity. L. 

 W. Austin, U. S. Naval Radio Research Laboratory. 



The theoretical predetermination of antenna capacity has 

 always, until recently, been a matter of great uncertainty. 

 Professor Howe^ in 19 14 published an article in the London 

 Electrician giving methods for the calculation of capacities of 

 elongated flat top antennas composed of parallel wires, and giving 

 tables and curves making it possible easily to determine the 

 capacities of small antennas of this type. In another article 

 he later also gave formulas^ for umbrella antennas. 



In 191 5 Doctor L. Cohen published antenna capacity formulas 

 in the Electrical World. ^ Very recently in Circular No. 74, 

 the Bureau of Standards^ gave formulas for elongated parallel 

 wire antenna capacities which are in very fair agreement with 

 observed values and also with the results of Professor Howe. 

 In all of these formulas, except where the results are given in 

 curves and tables, the calculations are more or less laborious, 

 and, of course, do not apply to antennas of other shapes than 

 those mentioned. 



It was discovered empirically during the past year that the 

 capacity of all antennas not too elongated in shape and having 



■ Howe, G. W. O. London Electrician 73: 829, 859, 906. 19 14. 



2 Op. cit. 75: 870. 1915. 



' Cohen, L. Electrical World 65: 286. 1915. 



* Bur. Stand. Cir. 74: 239. 1918. 



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