148 BELL SYSTEM TECHNICAL JOURNAL 



demonstration of simultaneous three-channel operation from this 

 station to ships was carried out with satisfactory results. 



Fig. 1 shows a general view of the outside of the transmitting 

 station at Deal Beach. The three steel towers form an equilateral 

 triangle of sides five hundred feet (150 m.) and each is one hundred 

 and sixty-five feet (50 m.) high. Steel cables to support the antennas 

 are strung between these towers and also three cables extending 

 inward support a fourth antenna which rises directly from the building 

 in the middle of the triangle. One antenna goes to the middle of 

 each of the first mentioned steel cables, so that there are a total of 

 four transmitting antennas. One of these is intended for use at six 

 hundred meters. The building is thirty by ninety feet (9.1 by 27.3 

 m.) and two stories high. The southern half comprises the operating 

 room which rises two full stories. The other part of the building is 

 taken up by an office, shop, power room, living and dining room and 

 kitchen, and by six bedrooms. 



Description of the Experimental Radio Stations 



The system as developed at Deal Beach consists of four transmitting 

 sets, operating into four separate, altho naturally coupled, antennas, 

 one set and antenna being intended primarily for 600 meter calling 

 and for emergency. The receiving station co-operating with Deal 

 Beach is located about a mile (1.6 km.) north of that station and 

 contains four receiving sets receiving energy from four loop antennas. 

 The transmitting sets are capable of putting about one kilowatt of 

 modulated radio frequency power into each antenna and are con- 

 trolled from a telephone switchboard into which run trunk lines from 

 New York City. A ten-pair telephone cable connects Deal Beach and 

 Elberon and another telephone switchboard at Elberon permits the 

 transfer of received signals back to the wire line. The radio station 

 operates, therefore, generally as a telephone repeater arranged for two- 

 way operation with two repeaters. At the ship stations, because of 

 the small amount of space involved, transmitting and receiving was 

 accomplished on the same antenna at different frequencies in the two 

 directions. Because of the better receiving conditions on the shore 

 the proper transmission balance was obtained by making the output 

 of the ship transmitting set about one-quarter that of the land station. 



The general principle of operation of one channel of the wire-to-radio 

 repeater will be described from the schematic circuit diagram of 

 Fig. 2, which shows, in the dotted blocks, one channel of the trans- 

 mitting station, a ship station, and one receiving set. At the trans- 

 mitter station the master oscillator, very carefully shielded to main- 



