Abstracts of Technical Articles from Bell System Sources 



Attenuation of Overland Radio Transmission in the Frequency Range 

 1.5 to 3.5 Megacycles per Second.^ C. N. Anderson. Data on the 

 effect of land upon radio transmission have been obtained during the 

 past few years in connection with various site surveys. These data 

 are for the general frequency range 1.5 to 3.5 megacycles per second 

 and for \arious combinations of overwater and overland transmission 

 as well as entirely overland. The generalizations in this paper are 

 chiefly in the form of curves which enable one to make approximations 

 of field strengths to be expected under the conditions noted above. 

 The relation of these data to transmission in the broadcast frequency 

 range is shown, and frorti the over-all picture, curves are developed 

 which enable field strength estimates to be made for overland trans- 

 mission in the extended frequency range. 



The Radio Patrol System of the City of New York."^ F. VV. Cunning- 

 ham and T. W. Rochester. The application of radiotelephony to 

 municipal police work in New York City is described from the organ- 

 ization, viewpoint. Brief references are made to historical backgrounds 

 and description of apparatus, and the steps taken to select a receiver 

 suitable for local conditions are outlined. The method of controlling 

 the patrol force by radio is described at some length with examples, 

 and a summary of results during the first year is given to show the 

 value of this means of communication to police work. 



Electrical Disturbances Apparently of Extraterrestrial Origin.^ Karl 

 G. Jansky. Electromagnetic waves of an unknown origin were 

 detected during a series of experiments on atmospherics at high 

 frequencies. Directional records have been taken of these waves for 

 a period of over a year. The data obtained from these records show 

 that the horizontal component of the direction of arrival changes 

 approximately 360 degrees in about 24 hours in a manner that is 

 accounted for by the daily rotation of the earth. Furthermore the 

 time at which these waves are a maximum and the direction from 

 which they come at that time changes gradually throughout the year 

 in a way that is accounted for by the rotation of the earth about the 



^Proc. I. R. E., October, 1933. 

 ^Proc. I. R. E., September, 1933. 

 ^Proc. I. R. E., October, 1933. 



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