276 



ILLINOIS STATE ACADEMY OF SCIENCE 



The above test, being quantitative, was fairly conclu- 

 sive proof that the potassium-sodium alloy content tubes 

 are superior to the gas filled or vacuum detectors. How- 

 ever, to be sure as to their practical utility, the tubes 

 were placed in standard receivers to receive the 2500 

 meter spark station at Arlington, the 17000 meter sta- 

 tion at Annapolis, and the 360 meter radiophone broad- 

 casting stations at Pittsburgh, Schenectady, N. Y., De- 

 troit, and Chicago. The results obtained were consist- 

 ent with the quantitative measurements. For receiving 



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the radiophone stations the tubes were used as oscillat- 

 ing detectors by the "zero beat" method, and also by the 

 heterody]ie method for the 17000 meter station, and the 

 writers and their assistants were astonished at the re- 

 sults. Speech and signal reception were remarkably loud 

 and distinct, and with practically no need of any fre- 

 quent readjustments, as are often necessary with gas 

 filled tubes. The tubes even functioned fairly well as 

 oscillating detectors with zero plate voltage, receiving 

 the above stations. They were also used as amplifiers 



