US956165A - Electrical space communication. - Google Patents

Description

v W. PIGKARD. ELEGTRIGAL SPACE COMMUNICATION.

APPLICATION FILED SEPT.3.1907.

Patented Apr. 26, 1910.

' A; Atty UNIT D STATESPATENT OFFICE. I

V GREENLEAF WHIYITIER PIGKABD, or AMESBURY, Massnonusnrrs,

ELECTRIGAL SPACE COMMUNICATION.

' Application filed September 3, 1907. -Seria1 No. 391,081.

To all whom it-ma'y concern:

Be it kno'wnthat I, GREENLEAF -WHITTIER PICKARD, a citizen of the United States of America, and a resident of the town of Amesbury, State of Massachusetts, have in-, vented certain new and useful Improvements in Electrical Space Communication,

.the principles of which are set forth in the following specification and accompanying drawing, which disclose the form of the invention which I now consider to be the best ofthe various forms in .which those prin'ci-' ples may be embodied.

, This invention relates to means: for conveying intelligence transmitted by electromagnetic waves.

One object of the invention, among others,

is-to concentrate at the receiving device as hereinafter described, to peri'nit'the convey- .through space in the form of electromag-.

I sensitive form of local receiving devices are ance to or from the local apparatus of the oscillating electrical energy transmltted netic waves.

Space telegraphy is now. practicable over moderate distances, of the orderof a few hundred miles. But for longer distances, of I the order of thousands of miles, the problem has heretofore been unsolved, as to how to collect or distribute an effectively large proportion of the transmitted energyfor use at a given receiving station or plurality of such stations. It is now possible to operate over such distances, only by employing uneconomically large amounts of transmittlng power and great extentof transmitting conductors; this being true even when the most employed, and even when the largest prac-' ticableextent of receiving-station conductors isemployed. "Other things being equal, the energy collected at a receiying station has depended upon the necessarily limited .ex-' tent of the receivin conductors there at, and the consequent limited degree of interposition of such receiving station conductors in' the path of the circumferentially widening v Waves. Owing to various mechanical andstation are quite sharply defined. Even -when the conductors are inultiplied at the station, there is little gain. The losses arevery reat indeed in transmitting thousands ofm' es to a given'receiving-station, which is only one minute point on theycircumference of the great circle of which the transmitting station is the center. T

4 A means for-concentrating at the local receiving devices a much greater amount of theenergy transmitted from a far-distant States Patent No. 836,531 of Nov. 20, 1906) C a suitabletelephone-shunt condenser, and C a suitable tuning condenser, all of which maybe replacedby any suitable devicesand circuits to constitute an operative combination of receiving devices; or by suitable local transmitting apparatus in any of the various lmown forms. be a wave-conductor at the station S, but 'there are severalsuch conductors (as many orfew, even only one, as desirable or converiient) geographically separated, as at M M M M, etc., which may be thousands of yards or more remote from local station S, and connected' thereto by lines L L L', L, etc., suitably constructed as; hereinafter electrical considerations, the limits to the extent of receiving conductors at a recelvlng There may or may not;

Specification of Letters Patent. j Patented Apr. 26, 1 9 1 0. i

source, and. for other purposes, is-diagnamdescribed By suitable means, hereinafter described, the effects of all these conductorstations may be added together to operate the local circuit at station S.. The

as practical or. economical permissible length of the specially-constructed lines L may depend' 2rd distance of the transmce the invention is use-- communication, such for example .as trans- ,amount of transmitted energy and energy asses in llne transmission, be the existing series of Atlantic coast stations 'on the United States seaboard (or others more or atlantically, the conductor stations M etc., may convemently, when practicable as to'- less remote from each other) the lines L etc., being led from local station S (which might conveniently be at the city of Washington) ,to each remote conductor-station M. The lines L maybe any suitably constructed existing telegra h or telephone lines, or such line,s of stran ed copper conductors provided with loading inductances I, like the long-distance telephone devices well known in the art as load coils, and inserted at more or less frequent intervals in general pursuance of existing practice on long-dis tance telephone lines,-but distributed or arranged in the lines in accordance'with this invention, with regard to the sh orter wavelengths in this art, of the transmitted impulses. In order to securewbeneficial effects,

the coils'l, which are preferably in the form of air core inductances, may be inserted at least at intervals ofg, wave length. The

amount of inductance inserted per unit of length may be such as to increase the line inductance to at least four times its value without the coils. If high insulation and low dielectric dissipation can be secured on the line conductors, a higher'ratio of loaded to unloaded inductance may be advantageously employed. By 'suitably loading these lines, the loss in transmission over,

them .is very slight, even in the case of the high frequency currents which may be employed with the'invention, and evenwhen the lines L are a number of miles long. The loading to reduce transmission losses is extremely important for long lines. The lines L are shown grounded in the usual manner, but may if desired be completely-metallic, and in that case loaded on each side in the manner of this invention. v

The station-conductors M may be of any desired type, but for receiving intelligence along the Atlantic coast from any point 1n Europe or from transatlantic shipping, for example, they are of my magnetic loop type (as at M and M, and described by me-in the Electrical Review, New York, June 22,

are long, is evident from the fact that the wave conductors M of any type cannot ex-' tend continuously from distant conductorstations to the local station, on account of the limitations of such station-conductors to definite proportions of the length of the space-transmitted waves, as well as on account of the phase-difference which would result at a local station caused by the operation of conductor stations separated by various and substantial distances from the 10- cal station. For example, in the case of. the magnetic loop, this particular type of waveconductor ought not to have an electrical lengtln in excess of a quarter of the length of the transmitted waves, because otherwise the reversals of direction of the magnetic lines and the consequent algebraic addition of positive and negative electromotive forces would reduce the effective energy; and the energy in such a wave-conductor would be further reduced by the presence of a material amount of loading inductance.

While in certain casesthe loading of the conductors may be dispensed with, yet it is in all cases advantageous, as the energy loss in the resistance of the wire is considerable in a non-loaded line conveying high frequency oscillations. A loaded line acts as a high'impedance line conveying energy at a high potential and with smallcurrent, so that the ,C R losses are greatly reduced.

Each of the conductor-stations M may be tuned to the far-distant transmitting station, as hereinafter described. Also the condenser C or inductance N at the local station S may be adjusted to syntonize the 10- cal circuit at station S with the station-conductors M. The \magnetic loop is particu-. larly valuable in this combination, not only on account of its inherent efiiciency, but because all the conductor-stations may usefully cooperate with respect to a single far-distant transmitting station, so that the loops,

fixed in one direction, will always be ready for the desired operation. Such receiving loopsare even more particularly useful in this invention when used with a similar magnetic transmitting loop at the far-distant transmitting station. The loaded lines L may be inductively connected. to the respective conductors M,.by oscillation transformers O 0 etc., having a'few turns in the primary and a larger number in the sec ondary. The lines L may be connected to the local circuit devices at station S by os cillation-transformer primaries P P etc., of say thirty or forty turns each, cooperating with the common secondary N of say, forty -or more turns in the local circuit at stations. The exact ratio of transformation employed will of coursebe determined by the im edance of the lines when loaded. In genera, the higher the loading or the impedance, thegreater the ratio of transformation will be. Of course, the invention may be more efiiciently employed by not in creasing the lengths of lines' L to such extent as to cause the sum of theC R losses in all the lines to approximate the difference between the energy received by a single conductor-station'M, and that received by theplurality of separated conductor stations. By using the special line's described above, however, the lengths of lines L may be made of comparatively great length. v

As is indicated in the drawings at M and M the loop conductor need not be high,

' and it may be supported by poles lower than those for lines L or else by poles of the same. height. At M and M is shown the simplest form of the magnetic loop, in which are employed the magnetic components of the waves. The tuning to the wave-frequency is by means of the .variable'condensers K and Kt] I- have found that the magnetic loop operates best, roducing louder results in telephone T, when it is connected (with or without the line conductor) to the local detector circuit b the step-up oscillation transformer P the primary P having two or three turns, and the seconda 'N of forty or more turns, the circuit of t e secondary permitting very. close tuning by varying either N or C and this steppingup of loaded ine, as that is of hlgh impedance,

working with high potential and small current flow. As a'general. rule the loop-cir- .cuit should have as low inductance aspossible, and be limited to the inductance of its conductor; but the advantages of the transformer P N more than compensate for the added inductance which the primary P constitutes, even when said primary isin eluded directly in the circuit of loop M or when, as here, the primary of transformer O is included in the loop-circuit. The oscillation transformer 0 connecting M with L, should preferably have a ratio of at least five to one, in order that the energy be delivered to the line at as high a potential as possible. At M -the-length oft-he loop is horizontal, so that it need not be high, as

stated above. The'ma' etic loop, however, maybe used with its figth vertically disposed, in order to enable the conductor to be advantageously used-to receive the electrostatic as well "as. the magnetic components of the waves, as by an earth connection from theprimaryf of the oscillation transformer and other suitable apparatus.

uWhen all the conductonstations M are a substantially equally distant (effectively) from the far-dlstant transmittlng station,

ii55l or from the distant ship. e uipped'with transmitting'japparatus, such at thewavea fronts strike al the station-conductors, at substantlally thesame time, (which-is a simplef matter arrange for, particularly 1n= very 'Zlong dlstancetransmission, where i the wave front is nearly a straight line),

the resulting1 oscillations will startalongthe. lines Lat es'ame instant, and will arrive at the local station S at. times depending upon the'length of the line and the velocity otential is advantageous with the 'of the oscillations If the various of oscillations do not reach the local station S at substantiall the same time, or at least in the same p ase, the maximum effect on the receiving devices will not be produced.

By suitably adjusting the velocity of the oscillations, the time of travel from all conductor-stations M along all the lines L to j a the local station. S may be made uniform,

or in such ratio to each other that they will arrive in phase, irrespective of the lengths of conditions 'governing velocity may be effected by adjusting the lines L in accordance with this'invention, the velocity with which an oscillation travels along a con- :ductor being represented. by the equation,

'where L is the inductance perunit length of the circuit, and C the'capacity ofi the conductor per unit length For the lines L,

the element. .C would be afixed quantity, andthe'velocity V can be'adjusted by the Variation of L, which. can be made of any desired value by varying the inductance of 1 load coils I. That is, in designing the lines 4 'L, in accordance with this, invention, they more of them lead from a conductor-station which is struck by the waves materially of the irespective lines L. This adjustment earlier or laterthan other conductor-stations geographically separated from station S. In cases where 1t may be practicable tolocate each of'the stations M the same distance away from local station S, it will be unnecessary to employ the load coils for controlling the oscillation-velocity, provided the line-conductors having the same length, have also vthe same inductance. And in cases where there is ample energy or slight transmission loss, the load coils may not be'required to reduce such losses.

' In accordancewith the above, the invention includes between the local station and the various conductor-stations, a corresponding number of transmissionlines so adjusted as to, bringall the. oscillating currents 1n phase, to the local receiving station, and adapted as loaded lines, ifdesired, for min mum transmission losses. Bymeans of properly loading the lines it is practicable to provide conductor-stations of such substantial distances from the local'station as to collect a comparatively .largeproportion 4 a I i of the transmittedene'rgy. "Thechief feature however is the means forcollecting at a local station, and all in phase, the various amounts of energyareceived at distant conductor stations, to be added together in the local receiving-circuit.

The invention is also useful, "when local transmitting apparatus of any of the wellknown types, and not necessarily provided with any wave-emitting conductor, is ineluded at the .local station represented by S, to transmit a message by waves from a distant wave-emitting conductor M, or to simultaneously transmit messages by waves from a plurality of conductor stations M M etc., acting as wave-sources; the energy being supplied over the lines L from the central source at S. Various other uses of the invention will be suggested by extended use, and the invention is hereby claimed forall its possible uses.

I clalm:

1.. Means for conveying intelligence communicated by electromagnetic waves, which. comprises a'local station, a plurality of conductor-stations separated from the local station by various and substantial distances, and so located with respect to. a distant transmitting station or stations as to operate effectively simultaneously with-the wavefronts; line conductors of correspondingly various lengths connecting the local station with the variously distant conductor-stations; oscillation-transformers connecting the ends of the line conductors with the apparatussat the local and conductor-stations; p

mun1cated by electromagnetic waves, which and load coils in the line-conductors to reduce transmission losses and transmit all the oscillating currents in phase.

2. Means for conveying intelligence communicatedby electromagnetic waves, which comprises a local station, a plurality of conductor-stations separated from the local station by various and substantial distances, oscillation-transformers at the local station and at the respective conductor stations; transmission lines of corresponding'lengths connecting the transformers; and load coils in the transmission-lines.

3 Means for conveying intelligence communlcated b electromagnetic waves, which comprises a coal. station, a plurality ofconductor-stations separated from the local station by various and substantial distances, line conductors of correspondingly various lengths connecting. the local station with the J variously distant conductor stations, and load coils included in the line conductors to cause the oscillations to arrive in'phase at the local station. I p

4. Means for conveying intelligence dommunicated. b electromagnetic waves, which comprises a ocal station a plurality of conductor-stations separated from the local sta- ;tion by substantial distances greater than one-half of the wave-length and so located stawith respect to.a distant transmitting tion as to be operative substantially slmult-aneously with respect to the wave-fronts,

and line conductors of lengths corresponding to the distances between the local station and the various conductor-stations, and connecting the various conductor-stations with the local station. I

, '5. Means for conveying intelligence communicated by electromagnetic waves from a far-distant transmitting station, which coniprises a local receiving statiolf, a plurality of, verticalmagnetic-loop receiving-con: ductor stations separated from the local Sta;- tion. by substantial distances greater than one-half of the wave-length, the vertical plane of each of the loops substantiallymco inciding with the radii of transmission from ductor-stations separated from the local station by substantial distances, line conductors connecting the distant conductor stations with the local station, and means for controlling the velocity of oscillation transmission along the line conductors.

7. Means for conveying intelligence comcomprises a local station, a plurality of conductor-stations separated from the local station by substantial distances, line conductors connecting-the distant conductor-stations with the local station, and inductance coils included'in said conn'ec'tin line-conductors to reduce the transmission losses. k

8. Means for conveying intelligence communicated by electromagnetic waves, which comprisesia local station, a plurality of conductor-stations separated from the local staistant tion by substantial distances, line conductors leading from the conductor. stations to the local station, and oscillation transformers connecting the ends of said connecting lineconductors to the apparatus at the respective.

conductor-stations and the local station.

9. Means for conveying intelligence comline conductors of correspondingly variouslengths connecting the distant conductor stations with the local station, said connecting 'municated byv electromagnetic waves, which v line conductors being constructed to causethe time of oscillation transmission in each of them, irrespective of their lengths to be such as to bring the oscillations in all of them in phase to the local station.

10. Means for. conveying intelligence com-- municated by electromagnetic waves which comprises a local station a plurality of conductor-stations se arated from the local station by substantlal distances greater than onehalf of the wave len h, and line conductors connecting the distant conductorstations with the local station.

11. Means for conveying intelligence communicated by electromagnetic waves, which comprises a local station, a conductor station separated a substantial distance therefrom, and a loaded transmission ,line con-v nected and adjusted to transmit oscillations I between the two stations with minimum 'stations to the localstation, and a transformer at the local station having a plurality of elements connected to the respective line conductors and a commomelement connected with the local station apparatus.

14. Means for conveying intelligence communicated by electromagnetic waves, which comprises a local receiving station, a plurality of conductor stations separated from the local station' by substantial distances, and loaded transmission lines connected and adjusted to conduct all the currents from the conductor stations to the local station in phase. Y 15. Means for receiving intelligence communicated by electromagnetic waves, which comprises a local receiving station, a pm rality .of' magnetic loop conductors sepa;

rated from the local station by substantial loop conductors with the local station, and

an oscillation transformer at the local station having a plurality of primaries each in circuit with one of the-lme conductors, said transformer having a common secondary cooperating with said primaries and,

with the receiving devices at the local station.

comprises a local station, a plurality of con- ;ductor-stations separated-from the local station by substantial distances, line-conductors connecting the conductor-stations with the local station, and means at said local station for controlling the velocity of oscillation transmission along the line conductors.

17. Means for conveying intelligence communicated by electromagnetic waves, which comprises a plurality of conductor-stations 16. Means for conveying intelligence communicated by electromagnetic waves, which distances, line conductors connecting said separated from the local station by various and substantial distances, line conductors of correspondingly various lengths connect- 7 ing the distant conductor-stations with the l'ocal'station, and means for producing such time of oscillation transmisslon along each of said connecting line conductors as to bring the oscillations in all of them in phase to the local station.

18. Means for conveying intelligence communicated by electromagnetic Waves, which i comprises a local station, aplurality of conductor-stations separated'from the local station by substantial .distances, and loaded line conductors connectin the conductorstations with the localstation.

19. Means for receiving intelligence communicated by electromagnetic waves, which comprises a local receiving station, -a plu rality of conductor-stations separated from said local station by substantial distances greater than one-half of the wave-length,

and means for collecting in phase at the local station to operate the same cumulatively, the various amounts of energy received from the transmitted waves by the various conductor-stations.

Witnesses:

EDWARD H. ROWEL'L, HENRY M. BRIGGS.

GREENLEAF WHITTIER PIOKARD.

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