July 19, 1921 eckhardt and karcher: radio recorder 



309- 



lations involve readjustments in the regenerative circuit when the 

 oscillation-stopping contact is opened. If, for example, the plate 

 inductance is short-circuited for the purpose of stopping the local oscil- 

 lations, the removal of the short involves reestablishment of a dif- 

 ference of potential at the terminals of this coil. This causes a surge 

 which tends to restart the oscillations and results in the recording of a 

 spurious signal. The method employed by us of stopping the oscilla- 

 tions involves no readjustments in the regenerative circuit when the 

 oscillation-destroying contact is opened and the system is restored ta 

 the receptive state. We are, therefore, enabled to work very much 

 nearer the critical grid potential with correspondingly enhanced sensi- 

 tivity. 



It is proposed to use the radio- 

 time recorder for the determination 

 of the longitude of any station. 

 This may be done by comparing in 

 turn the local time ascertained by 

 star observations and the radio- 

 time signal from a known longitude 

 with a local chronometer. It is,, 

 therefore, necessary to make sim- 

 ultaneous records on a chrono- 

 graphic drum of 



1. Local star transits against 

 local chronometer. 



2. Radio time signals against 

 local chronometer. 



From the data thus obtained,, 

 the longitude of the unknown 

 station may be computed with re- 

 ference to that of the radio time 

 signal sending station. 



RrCO/?D/Ne ELEMENT 



SAMPLE RECORD 

 Fig. 5. Circuit recording element. 



It is obviously desirable to have the same lag in the recording appar- 

 atus for both signals. If, therefore, both can be recorded by means of 

 the same mechanical system, i.e., with the same pen, a serious cause 

 of difference in lag has been eHminated. How this has been accom- 

 plished is illustrated in figure 5. The pen-operating magnet is differ- 

 entially wound with two coils of approximately equal resistance and 

 equal number of turns. The break-circuit chronometer operates a 

 relay similar to that in the radio recieving-recording set. The clock- 



