276 AUSTIN: ANTENNA AS HERTZIAN OSCILLATOR 



nothing to the radiation, the Hertzian oscillator which will radiate 

 the same amount of energy as the antenna will be 3 Vl-h. In 

 our case, however, this does not fully determine the value of I, 

 since the wireless room is some 30 feet above the water and 

 enclosed in the steel hull which is at approximately zero potential. 

 Then too, the exact height of the center of capacity of the antenna 

 system is a matter of some uncertainty. Since the lines of elec- 

 tric force to a large extent come down to the water and not to the 

 hull, it is probable that the point where the antenna leaves the 

 hull at the wireless room is somewhat too high to be taken as the 

 center of the oscillator. On the other hand, the center of capacity 

 of the antenna is certainly lower than the level of the flat top 

 antenna. As a probable approximation I have taken the height 

 from the wireless room to the antenna top, 29.2 meters as the 

 value of h. Then I = 41.3 m, A = 1000 m, the average sending 

 current of the two ships, J = 30 amperes. Then in c.g.s. units. 



4-1 3-1 O 3 3 

 E = 6.28 ---— — - 3-10 10 = 2.3410 5 c.g.s. = 2.34-10" 3 volts per 



1.10 1.10 centimeter 



The receiving electromotive force on the antenna will be 

 E-h = 2.34 -10- 3 X 2.92 -10 3 = 6.83 volts. The resistance of the 

 receiving antenna was approximately 25 ohms, thus, 



6 83 

 Calculated Received Current = — — = 0.27 amperes 



The corresponding observed value, that is the average of the two 

 values of K in Tables X and XI of the paper already cited, gives 



Observed Received Current =0.21 amperes. 



Considering the difficulties in determining the values of h 

 and the fact that a certain portion of the radiated energy must have 

 and the fact that a certain portion of the radiated energy must 

 have been absorbed by the rigging of the ships, the agreement 

 between the calculated and observed currents seems quite as 

 good as it is possible to expect. 



3 R. Ruedenberg Ann. d. Phys. 25: 446. 1908. 



