US1360167A - Antenna - Google Patents

Description

E. -F. W. ALEXANDEBSON. ANTENNA.

APPLICATION FILED SEPT. 13, 1917. 1,360,167. v

I Inventor: Ernst FTW. fllexanderon, b5 ,/%4W His Jqttorneg.

Patented Nov. 23, 1920.

2 SHEETS-SHEET I E. F. W. ALEXANDERSON.

ANTENNA.

APPLICATION FILED SEPT. 13, 1917.

Patented Nov. 23, 1920.

2 SHEETSSHEET 2.

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n o m 9 mm .m ia ow m DW%.$ Tlfi H m m b t h 9 f Nav N mm NN UNITED STATES PATENT OFFICE.

V ERNST ,F. W. ALEXANDERSON, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ANTENNA.

Specification of I ietters Patent.

Patented Nov. 23, 1920.

Application filed September 13, 1917. Serial No. 191,110.

To all whom it may concern.

Be it known that I, ERNST W. ALEX- ANDERSON, a citizen of the Unlted States,

residing at Schenectady, in the county of is a specification.

My present invention relates to antennae for radio signaling systems and more particularly to the manner in which the radiation of the transmitting system is effected. My present application isa continuation in part of my prior application Serial No.

123,276 filed Oct. 2, 1916.

The antenna of a radio signaling system as previously constructed has consisted of an elevated electrical conductor or a net work of conductors which is charged by a source of high frequency, energy in such a way that it becomes a source of energy radiation of the type known as the Hertzian os-' cillator. The theory-for the radiation of an antenna has therefore been universally treated by the mathematical The usual radiating antenna systemmay be considered as a single Hertzian oscillator. It has been proposed heretofore to employ a plurality of such oscillators in order to increase the amount of radiation or to secure directive effects but no practical use has been made of this idea because of the difficulties of controlling the phase'of the oscillations in the difieren't radiators in such a way that they would produce a combined radiation of a predetermined desired character.

One of the objects of my invention is to provide means whereby it will be possible to operate a plurality of practically separate radiators in such a way that a combined radiation of the desired character may be readily obtained.

There are several advantages which may I plainedbriefiy as follows:

In any single radiator, the strength of the electrostatic and the electromagnetic field of the radiated Wave is proportional to the theory v of the tems of waves are superimposed, they combine in such a way that the field intensity in any one place is the algebraic sum of the momentary intensities of all the separate waves. If a system consisting of a plurality of separate radiators is controlled in such a -way that the relative phase of the oscillations from the individual radiators is made to combine in a predetermined desired way, it will be possible to operate the system in such a manner that the field intensity in the a receiving station is the arithmetic sum of the field intensities produced by all of the individual radiators. A radiation of unity intensity from a station with a single ra'diator may be said to produce a field intensity of unity in the receiving station. tem comprising a plurality of radiators is operated in such a way that each of the radiators emits a wave of unity intensity, the effect on the receiving station will be the same as that of a wave with a field strength of as many times unity as there are individual radiators. The energy consumption of the single radiator may also be called unity and the energy consumption of each of the individual radiators of the multiple system will also be unity when operated as described. If then we assume that there are six individual radiators we will obtain with an energy consumption of six times that of the single radiator a field intensity at the receiving station which is six times as great as that obtained'with a single radiator. If it were, on the other hand, desired to produce by a single radiator, a wave at the receiving station having a field strength equal to six times unity it would be necessary to increase the current as well as the voltage in the single radiator to siX times unity and consequently the energy consumption of thesingle radiator would be 36 times unity. Thus it will be seen that the energy consumption of the single radiator will be six times as great as that of the six individual radiators in order to.produce the same intensity of signals.

If a 'sys- I A second advantage of my multiple radiation system is that it renders possible the production of signals of greater intensity than it has been possible to produce heretofore regardless of the amount of energy consumed. With any antenna there is a practical limit to the amount of radiation which may be obtained, thislimit being partially fixed by the maximum voltage for which it is practical to insulate the aerial. In other words, it is not possible to increase the strength of the signal above a certain value by increasing the amount of energy supplied to a single radiator. whereas with a plurality of individual radiators any increase in the signal strength desired may be obtained merely by increasing the number of radiators.

A third advantage of my system of multiple radiation is that it renders possible the production of a radiation of energy with a decided directive effect comparable with the focusing of a beam of light by a lens or a mirror. While the desirability of such an effect has frequently been mentioned and various means have been proposed for securing it none of the means heretofore proposed have been found to be applicable to practical operation.

A second object of my invention is to provide a convenient and practical means for adjusting the phase relations of the individual radiations so-that the advantages of directive radiation may be realized.

In the usual type of antenna correspond ing to a single 'Hertzian oscillator which has heretofore been used the energy is introduced through a ground lead in series with a loading coil.- In an antenna of this type designed for long distance transmission assume that the current introduced through the loading coil is 100 amperes and the potential of the aerial is 50.000 volts. The energy required to maintain oscillations in such an antenna may be 50 kilowatts. This means that the energy component of the oscillating voltage is 500 volts, or as it is commonly expressed,. the antenna has a resistance of 5 ohms. Thus the energy required for maintaining oscillations is delivered in the form of 100 amperes at 500 volts. While it might be possible to supply energy to each one of a plurality of radiators in this way such a method would. if the individual radiators were located at a considerable distance'fromeach other. involve unnecessary losses due to inductive or resistance drop in the feeding wires.

A further object of my invention is to provide a system for supplying energy to the individual radiators which will overcome this disadvantage.

In attaining this object of my invention I transform the energy to the form of high potential and low current and instead of supplying it at the ground point of the loadlug coil supply it at a high tension point. For example. in the case above mentioned, the energy-may be supplied to the radiators at 50.000 volts and one ampere. Thus while in each case 50 kilowatts of energy is required the old form of antenna consumes this energy in the same form as if it were a resistance of five ohms whereas the radiator supplied in accordance with my invention consumes the energy in the form of a resistance of 50.000 ohms. This may be explained by reason of the fact that in the old form of antenna the energy is introduced in series with the inductance and capacity or the antenna whereas in the form of a radiator which I employ the energy is introduced to a circuit which isthe equivalent of the antenna capacity in parallel with the inductance. By introducing the energy to the individual radiators in this way it is possible to feed a large number of such radiators located at a considerable distance from each other without incurring any great losses in the transmission conductors. In order to transform the energy into the desired form it might be possible to use a transformer of the ordinary type with the required ratio of transformation. I have found. however. that it is more convenient to use one of the radiating circuits as an oscillation transformer. and to supply the energy to all of the other radiators from the high tension end of the first radiator. In its preferred form then, my multiple radiating system may be considered as being made up of a primary radiator which at the same time serves as an oscillation transformer for supplying high tension energy t0 one or more secondary radiators. In order to have a completely balanced system of radiation. it might appear desirable to .ocate the primary radiator in such a way relative to the secondary radiators that the energy connections to each of the secondary radiators can be made directly to the primary radiator through wires of equal length. While this might be a practical method of construction. I have found in actual prac tice that it is not necessary toconnect each of the secondary radiators directly to the primary radiator and that it is of practical convenience in the construction of the antenna to connect the secondary radiators successively to each other. that is so that energy current flowing from the primary radiator reaches the secondary radiators in succession. In one case in which my invention has been applied in practice the antenna has the character of a horizontal transmission line supported on towers. This antenna is divided into a plurality of individual radiators by means of ground connections with loading coils therein at suitable intervals along its length. The aerial wires which serve as radiators also serve for transmitting energy to all of the successive radiators. Since the energy is transmitted to the secondary radiators in the form of high potential and low current it is apparent that a large number of radiators may be connected to such a transmission line without causing any appreciable changes in voltage and phase.

The novel features which I believe to be characteristic of my invention are set forth with'particularity in the appended claims. My invention itself however, both as to its organization and method of operation together with further objects and advantages thereof will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figures 1, 2 and 3 show diagrammatically as many different modifications and Fig. 41 is a diagram GXDlHnnl-nry of the directive radiation feature of my invention: In the form of my invention indicated in Fig. 1 the radiating system is composed of a plurality of horizontal conductors 1 of considerable length elevated above ground by means of the supports 2 from which they are insulated. This system is divided into five individual radiators by means of the ground connections 7, 8, 9, 10, and 11, individual tuning or loading coils 12, 13, 14, 15,

and 16 being included in each ground con nection. The ground connections indicated consist of a plurality of wires 17 stretched over the surface of the ground, the end of each conductor being permanently earthed. The energy for signaling purposes is supplied to the first radiator of the series by a high frequency alternator 18, connected through the transformer 19 to a transmission line 20 which conveys. the current to the transformer 21 by means of which it is introduced into ground connection 7.

j The first radiator comprises the ground connection 7 and the portions of the conductors 1 adjacent thereto and this radiator serves as an oscillation transformer to step up the voltage applied through transformer 21. Energy is thereby supplied directly at a high potential from the first radiator to the second radiator, which comprises the ground connection 8 and the portions of the conductors 1 adjacent thereto. The second radiator also acts as an oscillation transformer changing the high potential low current energy into the form of lower potential larger current producing an oscillating charging current in ground connection 8 which may be of the same magnitude as the charging current in ground connection 7. .The conductors 1 also serve as a transmlsdiators in succession. These radiators function in. the same manner as the second radiator so that charging currents of the same order of magnitude are set up in all of the ground connections. As an indication of the advantage which may be obtained by the use of my invention tests have been made with an antenna of the type shown in Fig. 1 which was divided up intd 6 individual radiators. When 50 kilowatts of-high frequency energy were supplied to the antenna and a single ground connection used a charging current of about 100 amperes' was obtained. When six ground connections were used the charging current in each ground connection was about 45 amperes making a total charging current of 270 amperes. In other words the effective radiation with the same amount of energy was about 2.7 times that which was obtained when the antenna was operated as a'single radiator. v

In accordance with the Hertzian theory of radiation the ability of a certain aerial to radiate is determined by the so-called radiation resistance. This radiation resist- For long distance working antennae of large horizontal dimensions are employed. The large horizontal dimensions give high electrostatic capacity and consequently the natural periodicity of the antennawhich is .determined by the physical dimensions of Thus if such an antenna the aerial is low. is operated at its nautral periodicity, or at a lower frequency the wave length is much greater than the height and consequently the ratio between height and wave length results in a low radiation resistance and a high ratio between the radiation resistance and the ground resistance; in other words, in low efficiency. The value to which the ground resistance may be reduced is also limited to a certain extent in practice by the physical dimensions of the antenna. lence it may be said that such an antenna when used as a simple Hertzian oscillator has a definite maximum possible efliciency or natural ratio between radiation resistance and ground resistance. When, however, the antenna is provided with a plurality of ground connections in accordance with my invention, its natural periodicity is increased beyond the value determined by its hysical dimensions when used as a simple ertzian oscillator,

that is, the natural periodicity of the entire antenna is equal to the natural periodicity of each individual section which is supplied with a ground connection, assuming that the naturalperiodicity of all of the sections is the same. In other words, the natural periodicity of the antenna is increased to a value much greater than the value which is determined by its physical dimensions. As

a result the antenna can be operated efficiently at much shorter wave lengths thereby increasing the radiation resistance inversely with the square of the wave length. The result of this is a more favorable ratlo between radiation resistance and ground resistance or efliciency of the antenna may be greatly increased.

The form of my invention illustrated in Fig. 2 differs from that shown in Fig. l merely in its constructional details. In this case each individual radiator takes the form of an umbrella type of antenna and the individual radiators areall connected by a transmission line 22 which supplies high potential energy from the first radiator 23 to the secondary. radiators 24. 25. 26 and 27 in succession. A radiating system constructed inthis way operates in the same manner as the one illustrated in Fi 1.

In Fig. 3 I have indicated a modification of my invention which may be employed when it is desired to obtain a directive effeet. are separated by inductances 28. 29 and 30 which may be made of such a value as to give thephase displacement in the waves radiated by successive radiators. re uired to secure the desired directive effect. f desired, condensers may be employed between the individual radiators instead of inductances.

In determining a method whereby a sys-.

tem comprising a plurality of individual radiators may be adapted for directive radiation an antenna such as illustrated in Figs.

1 or 2may be considered as a uniformly distributed capacity between a linear conductor andground. The electrostatic field surrounding the conductor extends in three directions but for the purpose of this discussion it will be suflicient to consider the potential gradient only in two directions, thatis in the vertical direction between conductor and ground and in the horizontal direction along the conductor. When an aerialconductor is set into oscillation by a source of continuous waves of definite frequency standing waves are formed in the electrostatic field. These waves must be analyzed in accordance with the horizontal as well as the vertical distribution of poten- In this case the individual radiators connection at one end has previously been used to considerable extent. If such a conductor 1S connected to ground through a large number of uniformly distributed coils,

it becomes a multiple radiating antenna as described previously. Furthermore, if the inductance of these coils is so adjusted that the oscillations in all of the different coils are substantially in phase the antenna may be said to have vertical oscillations but no horizontal oscillations. It is, however, possible to tune the antenna in such a way that -.it has both vertical and horizontal oscillations simultaneously. The vertical and horizontal oscillations may be of different frequency if a source of energy supply of more than one frequency is available. This might be the case if the antenna was excited by an arc generator or a pliotron oscillator. in the present case. however, it will be most convenient to consider the radiation as of a single frequency such as may occur if the antenna isexcited by a high frequency alternator. in which case the horizontal and ertical oscillations that take place simultaneously are necessarily of the same frequency. In the case where the conductor is connected to ground at one end only the horizontal oscillations occur in such a way that the grounded end is a node and the open end has maximum amplitude. It was at one time considered that an antenna of this type would produce a directive radia- 31011. it has now. however, been proved that this is not the case. the reason being that the length of the antenna has been less than one-fourth of the wave length of radiation at which it has been operated. whereas to secure an effective directive radiation it would be necessary that the length of the antenna should be at least equal to one-half of the wave length of radiation. In a simple horizontal antenna such as has been described the distribution of capacity and inductance has always been found to be such that the wave length of the standing wave along the antenna is shorter than the wave length of radiation. This condition, as will be explained more fully hereafter, prevents the securing of the most effective radiation. The fundamental rule which should be followed and which will be explained in the following discussion is that the wave length or the standing wave should be equal to or radiation is desired at right angles to the direction of the antenna the length of the standing wave should be infinity. For any intermediate angle the relative length of the standing wave and the radiation waveshould be equal to the secant ofthe-angle between the direction of radiation and the direction of the antenna. In order to prove this relation geometrically, assume that a wave begins to travel with the velocity of light from one end of the antenna. It is desirable in order to secure maximum efficiency of radiation that the wave as it travels along the antenna should always receive impulses which are in phase with the wave itself. For thisreason the standing wave should have a wave length equal to the wave length of the traveling wave. If an antenna oscillates with a standing wave which has a greater wavelength than the wave length of radiation, that is, if the wave travels along the antenna at a velocity greater than that of light, the difiterent points of the antenna may be assumed to emit radiation of different phases and the locus for points at which individual waves are of a certain phase may be represented by circles drawn around the diflerent centers of radiation.

Referring now to Fig. l, assume that the standing wave is represented by Z Around point a of the standing wave which is represented as a node a circle may be drawn having a radius equal to the wave length of ra di ation Z Around point 2) a circle may be drawn of a radius one-quarter of a wave length shorter. Around point 0 the circle has a radius of one-half a wave length and around point all a radius of one-quarter of a wave length. The line t which is tangent to all of these circles indicates the direction of radiation, the radiation being greatest in a direction perpendicular to this tangent, and it will be apparent from an inspection of this figure that l zl cos a: where a is the angle between the direction of the antenna and the direction of radiation. Applying the above formula to a case where the standing horizontal wave is shorter than the wave length of radiation the direction of such radiation would be expressed by a cosine greater than unity. This condition being impossible means that no directive radiation can take place and that the radiation will be inefficient.

The type of horizontal antenna connected to ground at one end which has previously been used as such distribution of inductance and capacity that the standing wave is theoretically equal to but in practice has been shorter than the wave length of radiation. In other words, the wave travels along the antenna at a velocity less than the velocity of light. If it is desired to increase the velocity at which the wave travels along the antenna and thereby lengthen the standing wave either the inductance or capacity must be decreased. Anythinghowever which is done in this direction by changing the combination of the Wires will defeat the object sought. An additional parallel wire will decrease the inductance but increase the capacity and fewer parallel wires will decrease the capacity but increase the inductance. B

the use of a plurality of radiators such asT have described the desired object may be attained. The capacity between the aerial and. ground may be neutralized by distributed inductance between the aerial and ground. If the distributed capacity is entirely neutralized by distributed inductance forthe frequency at which the antenna is excited thestandin wave will have a length equal to infinity, w ich means that all parts of the aerial conductor will oscillate in phase. This condition produces non-directive radiation if the antenna is shorter than half qf .the wave length of'radiation and directive radiation at right angles to the antenna if the antenna is sufliciently long in relation to the wave length of radiation. If a long antenna is used and directive radiation is desired atany angle except a right angle, thenecessary length for the standing wave may be determined from'the wave length of the radiation and the desired angle. The inductance of the aerial being known it will then be possible to calculate the amount of distrib uted capacity which will create a standing wave of the desired length. This requiredcapacity will be found to be lower than the capacity between the aerial and ground. The method to be followed then will be to neutralize the portion of the capacity to ground which is not desired, leaving a balance of distributed capacity'which will give a standing wave of the desired length. Instead of neutralizing the capacity to ground it will be possible to neutralize the longitudinal inductanceof the aerial conductor by series condensers. Both of these methods may be used in combination if desired.

If the method of adjusting the tuning of the antenna is considered from the above point of view it will be found that the method of radiation which consists in using a number of independent radiators excited from a common source of high frequency energy in such a way as to operate in phase is only a specific case ot a composite horizontal antenna with a horizontal standing wave. This specific case is one where the length of the standing wave is infinity and this method of radiation whether directive or nondirective may be differentiated from the methods of. radiation that have been transmission line which proposed heretofore by the characteristic that the standingwave has a length equal to or greater than the wave length of radiation, whereas such antennae as have been used previously have had standing waves of a wave length shorter than the wave length of radiation. The term "standing wave as used in the above description and in the claims which follow is not employed in the restricted sense in which it is commonly understood, namely, as the resultant of two waves traveling with equal velocity in opposite directions so as to produce points of large amplitude and intermediate nodes of zero amplitude. The phenomenon described by this term is also of a different nature than that known as a traveling wave since the latter term as ordinarily used implies a complete transfer of energy from one point to another at the same rate that the wave travels. While in the present case energy is transferred from one point to another this transfer is merely incidental as -a large portion of the energy remains fixed in position. Moreover. such transfer asidoes occur may take place in the opposite direction to the traveling wave effect. it any point along the length of the antenna the amplitude of oscillations is the same as at any other point, but when the standing wave, as the term is here used. is of finite length the oscillations of different portions of the antenna are displaced in phase. The maxima of successive portions occur in succession, however, so that the eifect. so far as the Wave in'the ether is concerned. is that of a traveling wave.

WhileI have illustrated and described the preferred form of my invention. it will be apparent that many modifications therein may be made without departing from the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

A radiating antenna system comprisin a primary radiating unit supplied by a s' rce of radio-frequency current and a plurality of secondary radiating units an individual ground connection for each of said radiating units, the secondary radiating units being connected successively to a supplies energy from the primary radiating unit to the secondary radiating units.

2. A radiating antenna system comprising a primary radiating unit and a plurality of secondary radiating unit's connected successively together and to the primary unit, an individual ground connection for each of said radiating units. a source of high frequency current connected to the primary unit, the primary radiating unit being directly connected to the first of said secondary units and serving as an oscillanon transformer for supplying energy suc- EGSSIVGlY to all of the secondary radiating lIllllS at a high potential.

3. A radiatin antenna system comprismg a set of horizontal aerial Wires, a plurality of inductance coils connected between said aerial Wires and ground at substantially uniformly distributed points along the length of said wires and a source of radio frequency current for supplying energy to the aerial Wires at one point, the energy thus supplied being distributed through the ierial wires to maintain synchronous oscil- .ations in each of the oscillating circuits formed by one of said inductances, and the :apacity to ground of the portions of the ierial wires adjacent thereto.

e. A radiating antenna system comprising i plurality of sections, all of the different sections being joined together successively ov aerial wires. each section consisting of aerial wires connected to ground through an 1nductance and forming a separate oscillating circuit. and a source of radio frequency :urrent for supplying energy to the aerial 'VII'GS which join the several sections, each oscillating circuit being tuned to the frequency of the energy thus supplied.

The method of supplying energy to a radiating system comprising a plurality of radiating units which consists in supplying energy to one of said units at a comparazivelv low potential. utilizing said unit as an )SClllElElOIl transformer for producing a com- )aratively high potential and distributing energy at the high potential thus produced from the first unit successively to all of the JUIIQI' units.

The method of maintainin synchronous oscillations in a plurality of radiating inits which consists in supplying radio frequency energy directly to one of said units ind supplying energy from said first unit successively to all of the other radiating mits.

The method of radiating electromagnetic energy from a system of horizontal *onductors which consists in producing an electrostatic field in said conductors which has a horizontal standing wave formed therein having a Wave length which is at .east as great as the wave length which is to ac radiated.

a The method of radiating electromagietic energy from a radiating antenna system which consists in producing by a single source of radio frequency energy an electrostatic field in said radiating system which has a horizontal standing wave formed therein having a wavelength which is at least as great as the wave length which is to be radiated.

l. A radiating antenna system comprising a set of aerial conductors. means for exciting said conductors by a single source of radio frequency energy, and means for neutralizing, by resonance, the distributed capacity between the aerial conductors and ground, the conductors being so arranged and said means beingso adjusted as to produce a standing wave of potential along the aerial conductor having a wave length at least as great as the wave length to be radiated.

10. A radiating antenna system comprising aerial conductors arranged in a horizontal line, a single source of radio frequency current for exciting said antenna system, a plurality of inductances distributed along said aerial conductors and connected between said conductors and ground, said conductors beingso arranged and said inductances being adjusted so as to partly neutralize the distributed capacity between the aerial conductor and ground in such a way that the distribution of potential along the aerial conductors will form a standing wave of a wave length at least as great as the wave length to be radiated.

11. The method of radiating electromagnetic energy which consists in charging an insulated continuous system of aerial conductors through a plurality of vertical grounded conductors connected thereto in multiple, the oscillating charging currents in the different ground conductors being regulated so as to have a progressive phase .displacement. 7

I 12. The method of radiating electromagnetic energy which consists in charging an insulated continuous system of aerial conductors through a plurality of vertical grounded conductors connected thereto in multiple, the oscillating charging currents in thedifferent ground conductors being regulated so that they are progressively shifted in phase to such a degree as to give a directive radiation in a desired direction.

13. The method of radiating electromag netic energy from a radiating antenna system which consists in neutralizing distributed capacity between said system and ground at a plurality of points .in the system, exciting said system by a single source of radio frequency energy, and producing a standing wave of potentialv along the system having a wave length at least as great as the wave length to be radiated.

14. The method of. creating an electromagnetic wave with a directive radiation in a system of" aerial wires having a plurality of inductance coils connected between said aerial wires and ground at substantially uniformly distributed points along said wires which consists in producing synchronous oscillating currents in all of the, ground conductors by means of energy introduced into the system through one ground conductor and regulating the currents in the different conductors so that they will have a progressive phase displacement.

15. The method of directive signaling which consists in supplying energy from a source of radio frequency current to a radiating unit, supplying energy from said radiating unit to a plurality of other radiating units and adjusting the relative phases of the currents in the different radiating units so that the waves emitted by all of the units add accumulatively at points in a. certain ductors, a plurality of 'vertical conductors each of which has one end connected to said aerial system and the other end grounded,

tors in such a way as to produce a directiveradiation.

18. The combination in a radio signaling system of an insulated system of aerial conductors, a plurality of vertical conductors eachof which has one end connected to said aerial system and the other end grounded, means for supplying energy to the entire system through one of said vertical conduc tors to produce synchronous oscillating currents in all of the vertical conductors and each of which has one end connected to said aerial system and the other end grounded, means for supplying energy to the entire system through one of said vertical conductors to produce synchronous oscillating currents in all of the vertical conductors and means for adjusting the relative phases of the different oscillating currents so that the interference effect of the waves produced creates a maximum amplitude of signal in a desired direction and a minimum amplitude in another direction.

20. A radiating antenna system comprising a continuous system of aerial conductors arranged in a horizontal line. a plurality of ground connect1ons for said system containing tuning means located at substantially uniformly distributed points along the length of said system whereby said system is divided into a plurality of radiating units capable of oscillating substantially independent of one another, and means for supplying energy to said system through a single one of said ground connections.

21. A radiating antenna system comprising a system of continuous elevated horizontal conductors, a plurality of ground connections for said system containing tuning means located at substantially uniformly distributed points along the length of said system whereby said system is divided into a plurality of radiating units capable of oscillating substantially independent of one another, and means for supplying energy to said system through the ground connection nearest one end whereby said elevated conductors serve both as a plurality of substantially independent radiating units, and to transmit energy at a high potential from the first radiator to the other radiators in succession.

22. An antenna for a wireless signaling system comprising a long horizontal continuous conducting network supported above the earth and connections between said network and earth at a plurality of successive points along its length whereby the natural periodicity of the antenna is increased beyond the value determined by its Iphysical dimensions when used as a simple ertzian oscillator, all of said earth connections including inductances adjusted in such a way that the multiple impedance of the inductances is equal to that of a single inductance necessary for tuning-the whole antenna at the operating frequency.

23. The combination in a wireless signaling system of an antenna comprising a long horizontal conducting network supported above the earth and connections between the said network and earth at-a plurality of successive points whereby the natural periodicity of the antenna is increased beyond the value determined by its ph sical dimensions when used as a simple ertzian oscillator, all of said earth connections including inductances, and means for supplying the energy necessary for maintaining oscillations of a single definite frequency in the entire system through one of the multiple paths to ground.

24. The combination in a wireless signaling system of an insulated system of long horizontal continuous aerial conductors, a plurality of successive vertical conductors each of which has one end connected to said aerial system and the other end grounded. and a source of sustained high frequency oscillations for producing synchronous oscillating currents of a single definite frequency in a plurality of multiple paths, each of which comprises a vertical conductor and the space capacity of a portion of the aerial.

25. The combination in a wireless signaling system of an insulated system of long horizontal continuous aerial conductors, a plurality of vertical conductors each of which has one end connected to said aerial tystem and the other end grounded, and a source of sustained high frequency oseillations for producing substantially in phase oscillating currents of a single definite frequency in all of the vertical conductors.

26. The combination in a wireless signaling system of an insulated system of long horizontal continuous aerial conductors, a plurality of vertical conductors each of which has one end connected to said aerial system and the other end grounded, and a source of sustained high frequency oscillations for producing oscillating currents of a single definite frequency in all of the vertical conductors which differ in phase from one another by less than 90.

37. An antenna for a wireless signaling -vstem comprising a long horizontal continuous conducting network supported above the earth and having of itself a low natural oeriodicitv and connections between said network and earth at a plurality of successive points along its length, whereby its natural periodicity is increased to a much greater value. all of said earth connections including inductances for tuning said antenna.

$8. The combination in a Wireless signaling system of an insulated system of continuous aerial conductors, a plurality of vertical conductors each of which has one end connected to said continuous aerial system tlld the other end grounded, means for proiucing synchronous oscillating currents in all of the vertical conductors. and means for adjusting the phase relation of the currents in the different vertical conductorsin such a way as to produce a directive radiation.

239. The combination in a wireless signaling system of an insulated system of continuous aerial conductors, a plurality of vertical conductors each of which has one end connected to said continuous aerial system and the other end grounded, means for producing synchronous oscillating currents in all of the vertical conductors, and means for idiusting the relative phases of the different oscillating currents so that the waves produced by these currents add accumulatively at points in a certain predetermined direction.

30. The combination in a wireless signaling system of an insulated system of continuous aerial conductors, a lurality of vertical conductors each of which has one end connected to said continuous aerial system and the other end grounded, means for producln synchronous osclllating currents in all 0 the vertical conductors, and means such natural constants that an electrical wave will travel along its length at a velocity less than the velocity of light, and means uniformly distributed along the length of said conductor for increasing the velocity at which an electrical wave will travel along the conductor.

32. An antenna for a wirelesssignaling system comprising a long horizontal conductor insulated from the earth and having such natural constants that an electrical wave will travel along its length at a velocity less than the velocity of light, and means uniformly distributed along the length of said conductor for increasing the velocity at which an electrical wave will travel along the conductor to a velocity at least equal to the velocity of light.

33. An antenna for a wireless signaling system comprising a long horizontal conductor insulated from earth and having such natural constants that an electrical wave Wlll travel along its length at a velocity less than the velocity of light, and a plurality of inductances uniformly distributed along the length of the conductor and connected between the conductor and earth for neutralizing a portion at least of the shunt capacity thereof and thereby increasing the velocity at which an electrical wave will travel along the conductor.

34. An antenna for a wireless signaling system comprising a long horizontal conductor insulated from earth and having and connected between the conductor and earth for neutralizing a portion at least of the shunt capacity thereof and thereby increasing the velocity at which an electrical wave will travel along the conductor to a velocity at least equal to the velocity of light.

35. An antenna for a wireless signaling system comprising a long horizontal conductor insulated from earth and having such natural constants that an electrical wave will travel along its length at a velocity less than the velocity of light, a plurality of inductances uniformly distributed along the length of the conductor and connected between the conductor and earth for neutralizing a portion at least of the shunt capacity thereof, and thereby increasing the velocity of the electrical Wave in the conductor, and a plurality of inductances connected in series with said conductor between the different earth points for decreasing the velocity of the electrical waves in the conductor to a desired value.

In witness whereof, I have hereunto set my hand this 11th day of September, 1917.

ERNST F. W. ALEXANDERSON.

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