156 BELL SYSTEM TECHNICAL JOURNAL 



arrangement was used in order to obtain flexibility in the experi- 

 ments. It enables the circuits to be continued inland as four-wire 

 circuits and permits of the switching operations being carried out with 

 a minimum effect upon the 2-way balance of the transmission system. 



The receiving station at Elberon is located on a rented plot of 

 ground and was not built in permanent form, since we did not regard 

 this location as entirely suitable for receiving from the Atlantic. 

 Reception is carried on the four channels by means of four loop 

 antennas operating into four receiving sets. A telephone switchboard 

 similar to that at Deal Beach provides for the connection to the wire 

 system. Of course, two telephone switchboards are not necessary 

 but one was installed at each station in order that we might deter- 

 mine by operating tests whether the control of the system should be 

 from the transmitting or the receiving station. 



The receiving sets as finally developed were extremely selective 

 and pass only a band of speech width with a large attenuation outside 

 this band. They will be described in another paper. 



Fig. 8 shows a front view of one of the experimental transmitters 

 used aboard ship. The lower half consists of power control apparatus. 

 Three 250 watt tubes are used of which one is a master oscillator, 

 one a power amplifier and one a modulator. The large capacity 

 tube was used as a master oscillator and only a very small part of its 

 output applied to the second power tube. This was done in order 

 to prevent reaction of the antenna system upon the oscillator. 



Apparatus of this type was installed on the Ontario and Gloucester 

 of the Merchants and Miners Line, and operated in conjunction 

 with Deal Beach and Green Harbor. Later another electrically 

 similar set was built by the General Electric Company and was in- 

 stalled and operated by the Radio Corporation on the steamship 

 America. This installation is illustrated in Fig. 9. 



Part II 



OPERATION OF THE COMBINED RADIO AND WIRE 



SYSTEM 



The development work as described in Part I had resulted in estab- 

 lishing an experimental ship-to-shore radio telephone plant of some 

 proportions. This will be seen by reference to the accompanying 

 map of Fig. 10 which gives a picture of the field setting, as it were, 

 of the experimental operations. The experimental plant included: 



Two operating shore stations — Deal Beach, New Jersey, and Green 

 Harbor, Massachusetts. 



