Abstracts of Technical Articles from Bell System Sources 



Notes on Radio Transmission} Clifford N. Anderson. Consid- 

 erable data on radio transmission have been obtained the past few 

 years in connection with the estabUshment and operation of various 

 radio-telephone services by the Bell System. It is the purpose of 

 these notes to present certain aspects of some of these data which may 

 be of interest in the development of a general physical picture of radio 

 transmission and in indicating the effects of disturbances accompanying 

 storms in the earth's magnetic field. 



The general results which are arrived at are: 



1. Neglecting short time fading, the maximum field strengths re- 

 ceived at a given point for frequencies up to at least 4 megacycles are 

 in general agreement with those calculated by the inverse-distance 

 law and the minimum field strengths (over-water transmission) are in 

 approximate agreement with those calculated by the Austin-Cohen 

 formula. 



2. There appears to be a daylight absorption band in the neighbor- 

 hood of 40 kilocycles (North Atlantic transmission) which reduces 

 minimum daytime fields in that vicinity below the minimum limit 

 given above. 



3. The effect of solar disturbances is to increase the absorption to 

 "sky wave" transmission throughout the entire radio-frequency 

 spectrum generally and to reduce or eliminate the 40-kilocycle absorp- 

 tion band, thereby increasing daylight fields for transmission on fre- 

 quencies in that vicinity. 



Electrolytic Phenomena in Oxide Coated Filaments.^ Joseph A. 

 Becker. A critical survey of the literature shows that the current 

 through the oxides in oxide coated filaments is carried by electrons, 

 negative oxygen ions, and positive barium ions. The proportion of 

 current carried by each depends upon the exact composition and 

 method of preparation of the oxide coating, on the heat treatment and 

 on previous electrolytic effects. Presumably the conductivity is 

 greatly affected by barium and oxygen dispersed through the oxide. 

 New experimental results show: 



^Proc. I. R. £., July, 1931. 

 * Trans. Electrochemical Soc, Vol. LIX, 1931. 



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