UL TRA-SIIOR I - \VA VE PROP A GA TION 



261 



inconsistent with the physical picture ^' ^' ^^' ^^ of ultra-short wave 

 propagation which has been confirmed by basic experimental data. 



Since the inverse-square-of-distance relationship (equation 5) which 

 results from this physical picture is so different from the exponential 

 relationship which results from the absorption assumption of previous 

 investigators, the question arises as to the possibility of reinterpreting 

 their data on the basis of this physical picture. The data presented 

 by Muyskens and Kraus as ¥\g. 2 of reference 15 has been replotted 

 in Fig. 5 of the present paper on logarithmic coordinates in order to 



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0.2 0.3 0.4 0.6 0.8 1.0 2.0 



DISTANCE FROM TRANSMITTER TO RECEIVER IN MILES 



3.0 4.0 5.0 



Fig. 5 — Attenuation curve for 5 meter transmission as replotted from paper by 

 Muyskens and Kraus, Proc. I. R. E., Vol. 21, p. 1306, Sept., 1933. The straight 

 heavy line shows an inverse-square of distance variation in accordance with the 

 physical picture. The thin curved line is a replot of the curve presented by Muyskens 

 and Kraus as representing these data by a variation according to an inverse-distance 

 times an exponential factor. It is evident that these data may be interpreted equally 

 well on the basis of the physical picture (heavy curve) as on the basis of the empirical 

 equation assumed by Muyskens and Kraus. 



facilitate reinterpretation on the basis of this physical picture. Fig- 

 ure 5 shows that it is possible to interpret their data as following an 

 inverse-square-of-distance law equally as well as an inverse-distance 

 law times an exponential factor.^^ In this interpretation little weight 



1^ Bertram Trevor and P. S. Carter, "Notes on Propagation of Waves Below 

 Ten Meters in Length," Proc. I. R. E., Vol. 21, pp. 387-426, Mar., 1933. 



"Carl R. Englund, Arthur B. Crawford and William W. Mumford, "Some 

 Results of a Study of Ultra-Short-Wave Transmission Phenomena," Proc. I. R. E., 

 Vol. 21, pp. 464-492, March, 1933 and Bell Sys. Tech. Jour., Vol. 12, pp. 197-227, 

 April, 1933. 



"* Comparison of Figs. 2 and 5 on an absolute basis is difficult. The lower density 

 of the buildings in Ann Arbor and the fact that the fixed antenna was located in as 

 open a space as possible at the corner of the roof, combine to reduce the effect of the 

 buildings in lowering the mean field strengths. Also the apparent absence of a 

 measurement of the radiated power in the Ann Arbor experiments precludes the 

 determination of the absolute value of the attenuation from the experimental data. 



