AUSTIN: ARC AND SPARK RADIO TRANSMISSION 519 



would have been completely readable by double repetition. The 

 very poor showing of the 6000 meter wave, compared with the 

 4000 and 7000 meter waves, is probably due to a defect in the 

 receiver at this wave length. 



One of the most interesting portions of the work was the study 

 of the behavior of the ticker and heterodyne under the condi- 

 tions of continuous atmospheric disturbance at Colon. The re- 

 ports indicate that the heterodyne is somewhat more sensitive 

 than the ticker, but that the difference is not very great. With 

 spark signals the note produced by both is unmusical and diffi- 

 cult to distinguish from the atmospherics, and both are inferior 

 to a good crystal detector in receiving weak 500 cycle signals 

 thni continuous atmospherics. With arc signals, however, the 

 case is entirely different. Here the slipping contact ticker pro- 

 duces the same rustling sound as in the case of the spark, but 

 the heterodyne produces a musical note of any pitch found most 

 suitable for reading thru the disturbances. 



