Transoceanic Telephone ServiceShort-Wave Stations

Planning and Construction of a Short-Wave Radio SystemBY F. A. COWAN'

Member, A. I. E. E.

TN the Spring of 1928 the use of the transatlantic As a first step, it was decided to establish the first unittelephone service which was inaugurated a year of a receiving center to be used for receiving in thispreviously with one long wavelength radio circuit country from England on a one way channel which

was increasing rapidly and gave promise of growing to would be associated with the then existing one way Newsuch proportions as to require a number of additional York-London channel in setting up a second completetelephone circuits by the end of 1929. In addition it transatlantic circuit. Plans for the initial and succeed-was considered desirable to broaden the scope of the ing steps, together with the desired completion dates,overseas service to include a telephone connection with are given in tabular form.South America. It was decided after careful considera-tion of the whole situation to provide these new circuitsby means of short wavelength radio. At that time there In carrying out a large program of work, particularlywas in operation a one way New York to London short when the work is of a pioneering character or when thewavelength channel which had been used during the interval between the starting date and the desiredsummer of 1927, and at times during the winter, to completion date is small, it is essential that all phases ofsupplement the existing long wavelength circuit. In the work be carefully scheduled and coordinated. Inthe opposite direction some transmission tests at short the early stages of the work on the short wave radiowavelengths had been made but no use had been made project a schedule of work covering each item in someof the channel for service. For the New York to London detail was worked out and distributed to all involved inchannel, an experimental transmitter at Deal Beach the development. To insure smooth progress of theN. J., was used and during the transmission tests from planning and construction work covered by thisEngland to this country, the signals were received with schedule, joint meetings between the engineers and theexperimental equipment located at Cliffwood, New representatives of the construction forces were held at

frequent intervals and those phases of the job needingScheduled special consideration were handled promptly.completion SELECTION OF THE SITES FOR THE TRANSMITTING ANDdate for RECEIVING CENTERS

Step serviceSince a large percentage of the overseas business

Receiving center with first receiving unit originates in New York, this city has been selected asfor second New York-London circuit. . June 1, 1928 the United States terminal of all the existing or proposed

Transmitting center with first transmit- overseas services in the Atlantic area. Another advan-ting unit and second receiving unit for tage in terminating the circuits at New York is thatthird New York-London circuit....... June 1, 1929 there is radiating from this point a veritable web of main

Second transmitting unit to release ex-perimental transmitter at Deal Beach. . Sept. 1, 1929 long distance trunk circuits which furnish ideal outlets

Third transmitting unit and third receiv- for that portion of the traffic to points other thaning unit for fourth New York-London New York.

circuit.Dec. 1, 1929 With New York fixed as the terminal point the se-Fourth transmitting unit and fourth re- lection of sites for the transmitting and receiving centers

ceiving unit for first New York-Buenos overned for bytransm ission considensAires circuit ..... Feb. 1, 1930 was governed primarily by transmission considerations.

Other factors, such as proximity of land lines for con-Jersey. A survey of the situation indicated that to care necting the centers with New York, cost of land, avail-properly for the extensive development being planned, ability of a reliable and adequate power supply, andit would be desirable to establish new transmitting and accessibility, also entered into the final selection of thereceiving centers to serve as the United States terminals sites. The availability of a reliable power source offor short wave circuits in the Atlantic area. comparatively large capacity is a more important factor

at the transmitting center. At the receiving points,

N.Y. AeiaTeehn&TeerpCoay, Ne ok since smaller amounts of power are required, the plantPresented at the Winter Convention of the A. I. E. E., New York, can be operated for several hours from storage batteries

N. Y., Jan. 27Y-31, 1930. and the use of a reserve gas engine driven power plant638

30-30

April 1930 COWAN: TRANSOCEANIC TELEPHONE SERVICE 639

is feasible. This is a fortunate condition since the com- between the two. These centers should in addition be soparative isolation required to reduce the likelihood of located with respect to each other that for the importantnoise interference from ignition systems of internal directions of transmission the normal directive charac-combustion engines or from electrical machinery usually teristics of the antennas assist in reducing the possibil-results in suitable receiving sites being somewhat ity of interference between transmission in the tworemote from the sources of power supply. Except for directions.the need of guarding against the possibility of electrical The sites actually selected by applying the principlesnoises at the receiving center, the transmission consid- discussed in the foregoing and their locations relative toerations governing the selection of sites are concerned each other are shown by Fig. 1, which indicates theprincipally with the locations of the transmitting and locations of the various transmitting and receivingreceiving stations relative to each other and in turn stations in the United States used in overseas radiowith their location relative to the circuit terminal at telephone service. The transmitting and receivingNew York and to radio stations of other communication centers for short wave use are all located within sixtyagencies. miles of New York. All of these stations are on, or veryWith respect to the desirable distance from New York near main cable routes and are connected with New

York city by cable circuits. They are readily accessibleby automobile. Special roads have either been con-

/ \ structed, or are now being constructed in those cases|c~A ,s0where the plots are off the main highways.

The transmitting center designated as Lawrenceville/' >Ssg D: having an area of about 900 acres, and the receiving

center designated as Netcong having an -area of about450 acres, are the recently established ones used in the

</ \ @# short wave system with which this paper is principallySJtXwni -e concerned. There are provided at present at theseIg; _ X\ S points, the United States terminals of the four overseas

;.\, yoM \ t---t1 telephone circuits, three to Europe, and one to Southr as America, the plans for which were discussed in the

foregoing. The centers have been planned to care forI ---'-' <''\ I\ \X Iadditional circuits in the future.

/ GENERAL LAYOUT AT LAWRENCEVILLEAO Cr.EGcE The buildings at Lawrenceville and Netcong are

- : ee AINS specially designed. At Lawrenceville there are atpresent two main buildings, each containing two radiotransmitters. Both buildings are of fireproof construc-

FIG. 1-LOCATION OF BELL SYSTEM OVERSEAS RADIO TRANS- tion employing reinforced concrete and hollow tile withMITTING AND RECEIVING STATIONS a brick exterior. The two buildings are identical with

regard to that part devoted to the radio transmitters.there appears to be no outstanding advantage in favor One of the buildings, however, contains more officeof locating short wavelength radio stations at a distance space, a line terminal room, a machine shop, and afrom the circuit terminal even when the radio transmis- garage which are intended to serve the entire centersion path could be appreciably shortened thereby. In when fully developed. The floor plans for the first andthe case of long wave radio transmission, however, there second floors of the main building which are about 75 byare greater advantages to be gained by shortening the 95 ft. are shown in Figs. 2 and 3.transmission path, and for the receiving station there is On the ground floor of each building, occupying thealso the added argument for securing a site sufficiently entire width at the rear, are transformer vaults andnortherly located to effect a material reduction in static rooms containing forced draft radiator units for coolingnoises. For this reason the receiving point of the long the water from the high power, water cooled vacuumwave radio circuit used between New York and London, tubes. Directly in front of these and also extending theis located at Houlton, Maine, some 600 miles from full width of the building, is a room containing the

New York. water-pumps, the regular and emergency motor-gen-Even when it is desirable to locate the radio stations erators and starters, and their transfer switches. Fig.

near the circuit terminal, as in the short wave system, 4 is a view of this equipment. Directly above the powerit is not practicable to locate them very near a city the room, and of equal floor area, is the transmitter room.size of New York. There is also the necessity of keeping The two transmitters are located in line on one side ofthe distance between the transmitting and receiving the room with their switchboards in line directly op-stations near the value which will minimize interference posite. They may be clearly seen in Fig. 5, which is a

640 COWAN: TRANSOCEANIC TELEPHONE SERVICE Transactions A. I. E. E.

general view from one end of the transmitter room. are interlocked to prevent incorrect manipulation andThe turrets containing voice frequency control and to protect men doing maintenance work.monitoring equipment may be observed in the center In general the layout of the equipment in the variousof the room. The overhead structure supports the rooms and vaults is such that one set is on the left of theradio transmission lines connecting the antennas to the building, a second on the right, and the common sparetransmitter, as well as the system of filtering lines used equipment in the middle. This simplifies the cablingin connecting the sleet melting power to the transmis- to the transfer switches which permit cutting the spare

equipment into service. The major elements of eachtransmitter which are likely to develop trouble andrequire an appreciable length of time to repair, areincluded in this spare equipment.

A l L1 t ; sThe central line terminal room, which contains the

So- 1= t1 _

FIG. 4-Room HOLDING PUMPS AND MOTOR GENERATORSFIG. 2-FiRST FLOOR PLAN, MAIN BUILDING AT

LAWRENCEVILLE, NEW JERSEY equipment for terminating and testing the cables fur-nishing the wire circuits to New York, is located on the

sion lines. Control of all equipment is centralized in second floor of the main building. Directly below itthe transmitter room and the attendants on duty remain the batteries and power equipment associated with thisthere except for routine inspections. The 10,000-volt equipment are located. The line terminal room isplate supply rectifiers are located in an extension of the electrically shielded by means of heavy copper sheeting,

FIG. 5-TRANSMITTEIR RoOM AT LAWRENCEVILLE

covering the floor, ceiling, and walls. The windows haveFIG. 3-SECOND FLOOR PLAN, MAIN BUILDING AT fine mesh gauze screen substituted for the copper sheet-

LAWRENCEVILLE, NEWJERSEY ing, and the door is provided with a metal coveringwhich is bonded to the copper sheeting of the walls.

transmitter room at a slightly higher floor level over This shielding is provided to prevent the high-powerthe middle transformer vaults. Beneath the rectifier radio frequency waves from feeding back into the lineroom and on each side of the center vault there are high- terminal equipment and c-ausing distortion or prevent-voltage switeh chambers each containing switch gear by ing the proper funetioning of the testing equipment.means of which the complete substitution of transformner In addition to the radio transmitting power equip-vault equipment from regular to spare may be effected ment associated with each transmitter individually orby the operation of a single switch handle in the trans- available for connection with either transmitter, eachmitter room. All switches and apparatus compartments of the buildings is provided with transformers to supply

April 1930 COWAN: TRANSOCEANIC TELEPHONE SERVICE 641

power for lights, machine shop operation, vacuum tube To secure the proper characteristics it is necessary intesting, and other uses. The power for all purposes is some cases that the antenna arrays have a height ofprovided from two outdoor substations, one for each about 150 ft., so to secure flexibility and allow for sag inbuilding, having a total capacity of 1200 kv-a. Each the supporting cable, the supporting towers have beenof these substations is located in the rear of the building made a uniform height of 185 ft. The towers wereit serves. Separate power cables leading to the various specially designed to meet the unusually severe condi-power units within the buildings are equipped with oil tions likely to be imposed at times by high winds andcircuit breakers and disconnecting switches which per- ice acting upon the antenna arrays. It may be ofmit the isolation of a unit in trouble for repair without interest to note that antennas of the type used, act veryshutting down the unaffected units. Both the power much like huge curtains suspended from the towers andconnections and the telephone circuits to New York in consequence the overturning moment at times ofare brought into the property in underground cables to cross winds is very large. In consideration of this, theprevent pick-up of the radio signals causing insulation cross section of the towers has been made rectangularbreakdowns or other troubles. The entire power and rather than square, with the long axis of the rectangletelephone layout is provided with spare equipment, perpendicular to the line of the towers. Head guys havecables, and switching mechanisms, so as to minimize been placed on the end towers and the entire line tiedthe possibility of a service interruption of serious mag- together by guys between the tops of towers. To min-nitude, due to trouble in power or telephone connections. imize any possible reaction upon the antennas theseAs in the case of the switches within the building all guys have been sectionalized with high-voltage strainpower switches and compartments are interlocked to insulators. The regular interval used between insula-prevent improper operation.As pointed out in a paper by Mr. Bown, satisfactory

short wave transmission requires wide changes in wavelength to meet changes in the time of day, season, orother conditions. For usual conditions three selectedwavelengths will cover the variety of requirementsencountered fairly adequately, but at times additionalwavelengths prove advantageous. For this reason oneof the circuits to England has five wavelengths assignedalthough the South American circuit and the remainingtwo to England have only three assignments. A sepa-rate antenna is required for each wavelength. There-fore the transmitting antenna system for the four ex- FIG. 6-AERIAL VIEW OF THE LAWRENCEVILLE CENTERisting circuits provides for 14 distinct antennas, 11 for Showing the antenna towers and the two transmitter buildingstransmission to England, and 3 for transmission toSouth America. Each of the regular antennas comprisesan exciting and reflecting array supported in the space tors is varied with the wavelength of the antenna andbetween three towers located in a line. For all but one ranges from around 25 ft. for the lowest wavelength toantenna the spacing of towers for the antennas is 250 ft. about 120 ft. for the highest wavelength.A greater separation is required for the antenna used in The towers are equipped with unusually large con-operation at a wavelength of about 45 meters, and the crete foundations, the dead weight of which alone istowers are therefore spaced 365 ft. apart. The an- calculated to be sufficient to prevent overturning at thetennas for transmitting in the same direction are located highest cross wind velocities anticipated. Anotherend to end in the same line. This permits supporting interesting feature of the tower system is the provisionantennas from both sides of all towers in a line except which must be made for lowering and raising the an-the two end ones. This close spacing of antennas is tenna curtains to permit repairs or adjustments. Formade possible by arranging the order of the antennas this purpose four winches are located at the base of eachwith respect to wavelength so that adjacent ones are of the towers in a line, except the end towers which havevery different in wavelenghts. The antennas for trans- only two winches. The winches are provided with twomitting to England are supported by 21 towers located gear ratios to meet the varying load conditions likely toin a line about a mile long, running approximately be encountered.northwest and southeast, and those for transmitting to The Lawrenceville station is located in the line ofSouth America are supported by seven towers in a line ffight of a regularly flown air route, and to guard againstabout a third of a mile long, running almost east and accidents the towers have been lighted in accordancewest. These two lines form a huge V when viewed from with the latest recommendations of the Department ofthe air. Fig. 6 is an aerial picture of the Lawrenceville Commerce. All told over 150 lights are used for thiscenter showing the antenna towers and the two trans- purpose. At the ends of each row of towers larger lightsmitter buildings. having 1000 candlepower are used.

;42 COWAN: TRANSOCEANIC TELEPHONE SERVICE Transactions A. 1. E. E.

The antenna curtain is supported by cables running service concentrated therein, is a substantially fireprooffrom tower to tower and attached at each end to the building of brick construction. This building provideswinches. These cables, which are called main supporting office space, a line terminal room, a central power trans-cables, are sectionalized in the same manner as the guy former station, and an emergency gasoline engine drivencables. The antenna curtains hanging from the main power plant. The line terminal room is electricallysupporting cables are kept taut by vertical and hori- shielded in the same manner as described for the trans-zontal stay wires equipped with counter weights. Be- mitting center, but in this instance to prevent thelow the curtains the transformers used in combining radiation of radio frequency noise to the antennas rather

than to protect the apparatus from interference.s ..# .* The central terminal and administration building is

.# ~ . . so located on the property as to be the first point reached*~452~i~4~t:4t~ . ~when entering by the main entrance road. To guard

FIG. 9-RECEIVER BUILDING AT NETCONG

Fin;. 7-LINE>; FEEDING~LAWRENCE VILLE STATION Tlhis building also liouises temporarily the line terminal e(lllipmienttagainst automobile interference, all but selected cars

the various parts of antenna are located. These trans- are stopped at this building and the journey from thatformers are actually parallel brass tubes one-quarter point continued on foot or by special transportation.wavelength long, spaced the proper distance apart and The individual channel receiving stations are smallsupported by power type insulators on wooden frame- wooden frame buildings. This type of structure was

adopted because the receiving art is developing rapidlyand receiving equipment is not thought to have thesame permanency as transmitting equipment. Also incase of fire the service affected would be limited and

j equipment of this type could be replaced rapidly with

FiO. `8-TRANSMITTING A NTENNA AT LAWRENCEVILLAE

works. A view of the antenna transformers and asso-ciated transmission lines is shown in Figs. 7 and 8. Fin. 10-PAIRT OF TER3,INAL AND TESTING EqUIPMENT AT

NEw YORK TERMINAL OF OVERSEAS CIRCUITSGENERAL LAYOUT AT NETCONG

At the Netcong receiving center the development has a minimum of lost time. A photograph of one of thebeen along the line of setting up separate receiving units receiving buildings is shown in Fig. 9. The equipmentfor the different channels at various points and bringing in these buildings is located in two rooms, one for thethe rec-eived signals into a central line terminal station. radio receiving set proper and the other for the powerThe central station, because of the importance of the supply consisting of storage batteries with charging and

April 1930 COWAN: TRANSOCEANIC TELEPHONE SERVICE 643

voltage regulating equipment. This latter room is RESULTSshielded in the same manner as the line terminal room The construction work on this project occupied ain the central terminal and administration building to period of about two years from start to finish. Some ofprevent radio frequency noise from this equipment the work was carried out under particularly tryingbeing radiated and picked up by the antennas. Power conditions. At times very unfavorable weather condi-and telephone connections for these buildings come tions were encountered. A considerable portion of thefrom the-central terminal building in cable. construction involved new types of plant for whichEach receiving building has three or more antennas there was neither precedent to be followed as to pro-

grouped around it, one for each wavelength received. cedure nor experience with which to establish the neces-These antennas are supported by huge wooden frame sary time intervals accurately. By careful coordinationstructures. The size of these frameworks varieswith of the work, however, the desired completion datesthe wavelength to be received. Expressed in terms of for the various parts of the project were realized. Thewavelengths the dimensions are about as follows, 1 three additional European circuits have been placed inwavelength wide, from 13 to 12 wavelength high, and service and tests are now in progress looking towards4 to 6 wavelengths long. The long axis of the structure establishing a New York-Buenos Aires circuit.is perpendicular to the direction of desired reception.The upright and horizontal members of the structureare bolted together with fish plates and strengthened Discussionby cross bracing. The entire framework is carried on TRANSOCEANIC TELEPHONE SERVICEconcrete foundations which have been made especially (MILLER, BOWN, OSWALD, AND COWAN)large to prevent the antenna overturning in high winds Bn Wf YORK, N. Y., JANUARY 30, 1930e to p t

. Bancroft Gherardi: The engineer from the very nature ofor getting out of alinement due to settling. The active his work is necessarily chiefly concerned with the technicalelements made up of copper tubes are supported on the aspects of such a question as is before us this morning, thesides of the structure with "stand off" insulators. The improvement and extension of communication service. But as

transmission lines from the antennas to the receiving engineers we don't want to have altogether out of mind the socialstations are concentric copper pipes supported about and economic results that may be expected to follow from what

we are doing.one foot above the ground by driven iron stakes. To Going back only about fifteen years ago to 1915, universalcare for expansion and contraction with temperature, telephone service did not exist even throughout theUnited States.these pipe lines are made to follow curving paths. The eastern part of the United States could not telephone to the

In addition to the regular receiving units there is western part of the United States, or vice versa. By develop-ments that had been made in the preceding few years, however,

another receiving station at the Netcong center which in 1915 the two coasts of the United States were tied togetheris provided with a receiving set arranged for accurate telephonically. So that we can really say from 1915 on we hadfield strength measurements and other radio testing within the United States and with our sister country Canada,equipment. This unit is called the Channel Observing service which extended practically wherever there were settle-Station. This station maintains a continuous check on ments of any size.

the radio transmissio conditionsandThis, however, by no means gave universal service, althoughthe radio transmission conditions and advises the New as many of you know, it has been for many years the policy andYork Control office as to the opportune time for the the aim of the Bell System to give universal telephone service sochanges in wavelength which are necessary from time that anyone at any time, could talk to anyone else quickly,to time each day. Very accurate measurements of the clearly, and conveniently.

received signals can also be made by the An enormous advance has been made since 1915. Most of

franneque ofserving station.Incase * e Europe has been brought into the picture. The possibility ofchannel observing station. In case Of interference to communicating with ships at sea has been demonstrated, and onethe telephone circuits from radio stations assigned to of our large transatlantic liners, the Leviathan, is now equippedneighboring wavelengths such measurements facilitate for the giving of commercial telephone service and has given suchthe correction of the difficulty. service on her most recent transatlantic trip.

In addition, the development in a sister art has created stillTERMINAL ARRANGEMENTS another problem for the telephone engineers. As airships have

developed the problem comes up of communicating with airships,The New York terminal of the overseas circuits is and the technical features of that problem have been solved.

located in the Telephone Building at 24 Walker Street, Mr. Miller has told you some of the proposed extensions ofwhich building is also the long distance office serving intercontinental service which are under way. I do not think hethe greater part of the New York metropolitan area. mentioned the fact that a station is planned and under way on the,"1T ., . . I -I.I I . 1 Pacific Coast looking toward the West and doing our part in

The pecil teminaing nd estig eqipmet islo-making it possible to communicate with the Islands of thecated on the twenty-fourth floor of this building. There Pacific and with the Continent of Asia. So it is not going too farare at present eight units which are used for the various to say that the scientists, the research experts, and the engineersoverseas services, four being used for the short wave have done their part to render universal telephone servicesystems we have been considering. Fig. 10 shows a practicable, and that the applications have gone a long way to

of theequipment in this room~.Frm h make such service a reality. Mr. Miller mentioned the fact thatportion today from New York City or any other place in the Unitedterminal room the circuits go to the long distance States or Ca,na,da,, it is possible to communicate with about 85 perswitchboard where the operators are located, cent of all the telephones in the world.