RADIO TELEPHONE SERVICE TO SHIPS AT SEA 



421 



stages are separately shielded and radio-frequency filters are provided 

 in all power supply leads. 



The power amplifier consists of an air-cooled, three-element, one- 

 kilowatt tube. Neutralization is accomplished by the familiar balanc- 

 ing arrangement shown in the figure. The output circuit of this stage 

 consists of a parallel resonant circuit with provision for tapping in the 

 connection to the antenna. 



Fig. 12— Leviathan transmitter. 



Modulation takes place in the plate circuit of the final amplifier stage, 

 the plate current supply being fed through a special transformer, the 

 secondary of which is connected to two 250-watt tubes connected push- 

 pull and fed by a 50-watt amplifier. 



The power supply is obtained from motor-generator sets operated 

 from the 110-volt, d-c. ship supply. Protection of the operators and 



