338 



AUSTIN: COIL ANTENNAS 



bulb circuit. The received currents in all three cases were mea- 

 sured with shunted detectors and galvanometers,^ calibrated and 

 tested for proportionality between deflection and current squared 

 in each experiment. 



In each of the tables, for the sake of comparison, the results 

 are reduced to a common value of sending current and a common 

 receiving resistance. 



The observed values in tables i and 2 are seen to be uniformly 

 larger than the calculated. This is supposed to be due to an 

 action of the coil as an antenna since an increase in the length of 



TABLE 4 

 Comparison op Antennas and Cons 



the leads increases this difference. When the lower side of the 

 coil is on or close to the ground, there is also an effect due to 

 radio frequency earth currents just as in the case of the ground 

 antenna. The reason for the increased error at the shorter wave 

 lenghts is not yet clear. The agreement of observed and cal- 

 culated values in the case of the coil sending (table 3) is all 

 that could be desired. From this, sending from a coil and re- 

 8 This Journai, 8: 569. 1918. 



