USRE12168E - fessenden - Google Patents

Description

No. 12,168. REISSUED NOV. 10, 1903. R. A. FESSENDEN.

WIRELESS TELEGRAPHY.

APPLICATION IILED OUT. 20. 1903.

Wi'bzeases: I rental":

I 6 v I m, ubzmv 7 i I iteis'sued fioveniber 10, I

{UNITED {STA ES} PATENT QFFICE,

" r;. REGINALD A. 'FESSENDEN, OFW SHI NGTON DISTRICT OF COLUMBIA,-

- ASSIGNOR 013" ONE-Turnip- TO DARWTY'S, WOLCOTT,'OF SEWIOKLEY,.

P NNSY ANI A WlRE LESSQT ELEGRAPI- IY.

srncrrresrrfon relgin pm of Reissued Letters Patent Nb. 12,16 dated November i0, 1905; mi ra ne. 706.737.1latad Au ust 1-2, 1902. Application for reissue filed eater-2p. 190s. Bunnie-177,820.

DIVISIONA. .0

T. ibal z-whg'ia it may concern: bers of a receiving instrument, one nieinber- Be itknoWnthatL'REGINALD'A.FESSENDEN, thereof consisting of a constant or indepe'nd "a citizen .of the United States, formerly residentlyf-yaryirig magnetic field, thesendinging at Allegheny, in the county of Allegheny, conductor is so constructed that itsjeapa'city 5 5 5 inthe State. of Pennsylvania, but nowres1d-'*or self-induction; o'r'both, are large: as comingfagtiwashington, in the District of 00111111 pared with the value of theaerialiwire corn: b ia, have, invented or-discovered certain new -'monly used in- 'the art and. disin'ili'i' tefi with "and useful Improvements in Wireless Telegpractical uniformity aloi'lgthe conductor fron raphy, of which improvements the following ornear its top to a poin -at-or near the'inst'rm fio lois'a'spejcification ment. By thusjincreasing the capacity and Theinvenion described herein relatesto' self-induction of either-of them thefreq'uency .certain improvements in transmission of enof the electric oscillations in the conductors, 'erg 3't5by electromagnetic waves,'and'has for and consequently of the waves generated, 7

itsfobjeet the I production of more.eflicient will be suiiiciently'lowto produ'ce utiliiable 63 sending'ier generating conductors. motion in the instrument, By low fre- It isiia, further object of the-inventionjto queney is ineant low relative to the fre-' provide:'for the "production of; mechanical quency hitherto used in wireless telegraphy. Inoveinentsby the' 'd-irect' interaction of eur- The terms sending-conductor: and frerents induced in the receiving-cont] uctor by ceiving-condnetor as hereinafter employed 7o eledtro nagn'e'ticwavesand constant or varyindicate allof the circuits of the-sending'and ing-magnetie 'fifilds. g receiving stations.- fro'ni'top to ground, if f, I 'flhe inventior i's hereinafter more fully degrounded, 0'r, f if not grounded, froni one exscribedand'claimede 'treme end to the'otherextreine. end, includ- In thefaceompanying drawings, forming a ingV-all apparatus inserieswith the circuits, 7 z 5 part ofthisjspecification; Figure 1. is adia- While the term if radiating portion indicates grammatie-view illustrating a form of appa- 'substantiallyxall of the sending -c onductor musthe practice of nay-invention. Eig. from top or extreme end of sauieto a point 1 2Jis a-fsnn arfvie'vv illustrating'a modification at or near ,iunctionwith'the apparatus for offlt eapparatns at the receiving-statioml effecting the oscillatory charging and disgo -FigLfi-is a'section'al elevation of one forln of charging thereof, suchas sparking terminals, conductor. Fig.4 is'a to plan' viewof the transformnncoils, armature-windings, 8m. 7

. ame,- 'and-F-ig. 5 is an elevationof a'modifi-' The self-induction of the sending-conductor. cationdf thejconductor. t can be regulated by increasing or decreasing In the eiiperimentsheretofore made in wiretheturns inthe coil 2, formed in the-wirecon- V 5 lesstransmission of energ a's'intelegraphy, eating the radiating portion 1 with the genrelatively high. frequencies-e. g'.'-, of the Q11;- erator 3': The capacity of the sending-con den of two inillion (2,000,000) periods or me e, ductorcan be regulated'in several ways as, perseeond 'have been used'; It is impossivfor example, by changing the superficial area 1 ble to produce or utilize 'mechanical'm'oveof theradiating port-ion 1by the employ- 9o orments directly by the intera'ctionpfa con 'm'ent of amediuin as described in vapplieastan'tprindependently-varyingmagneticfieldtiou No.. 62,303., filed May-29, 1901, or refine 1 and. a curie'ntinduced by electromagnetic ing'the height 'of the radiating portion-withwaves of such high 'riodic 'ties,' fo'r the ref Bout reducing its superficial areal] A con son that either theelenient to be 1noved'(as "duetor'ofi largeeapacitylniaybeconstructed, 5 the diaphragm of a telephonefiisf' incapable as shbyvfi'in Fig.- 3, havingjits radiating poi: Y of such rapid vibrationsorjtheyibrations are ti njI-in the form" of a cylindrical cage, contoo rapid. to beutilized;- Injorder-toutilize sisti-ngjbf a nulnber'of "parallel w-ires4, sedirectly the interaction between euri ents'i ,pufgj at theirends to supporting-rings 5, produced by electromagnetic wavesand acon i 'with'hubs or central sockets .6 for the 10: E50 .stant}J01,lindependentlysvarying -magfnetic. epti'oii (it-supporting -*ro ds 7,.formed of field toproduce motion' in one of twbtfmem bainb'oo or f-other light non-conducting matef rial. For convenience it is preferred to form the cylindrical cage in sections, which canbe.

meehanically-and electrically connected by the supporting-rings, as shown. This wire cage or cylinder can be connected to ground in any-suitable manner, as by the .wire 8, in which coils or turnsmay be formed to adjust the self-induction of the sending-conductor. As shown in Fig. 5, the radiating portion may be formed by a cylinder 9, having continuous metal walls. By employment of sending-conductors having large capacity distributed with approximate uniformity or regularity over a large portion of .its length the height. thereof may be reduced wit out affecting the eificient travel of the elect omagnetic waves radiated therefrom. lVhen low frequency is obtainedby increasing the capacity alone, or by increasing both capacity and self-induction, the curve of refinance is broader than is obtained byincreasing the self-inductance alone, though in the former cases the amount of energy radiated vfor a given voltage and length of sending-conductor ismore than is obtainable with a short resonance curve. Hence to obtain the best results it is preferred to use thetwo former methods and to conjoin with them at the'receiving-station means for increasingthe selective effect of the receiving-conductor, which means are described and claimed in application No. 62,303, filed May 29, 1901.

By increasing the capaclty and self-induction, or eitherof them, the'stated advantages of a low frequency of oscillations in the conductor and a shorter radiating portion are obtained, and in addition thereto it is possible with frequencies of one hundred thousand (100,000) or less to substitute for the inductioncoil, connected in. the .manner now in vogue, a source of alternating voltage as the exciting-geperator as,for examplatheex zitinggenerator may be a dynamo, a transformer connectedtoadynamo, oran inductioncoil producing low-frequency oscillations in a primary circuit, the'secondary circuit forming the source of alternating voltage and having one terminal connected to the radiating portion and the other terminal to the ground.

In order that a dynamo may be used to pro duce such a high periodicity which, though low as compared with periodicities heretofore used in wireless'transmission of energy, as in telegraphy, is very high as compared with those generated by dynamos commonly used in electrical engineering, it must possess several distinct characteristics. First, it

shouid generate pure sine-waves, because, as is well known, this is the only form of I a dynamogiving such a curve forming a part curve which gives perfect resonance. With of a suitably-constructed sending-conductor it is possible to wind the. dynamo so as to generate, for example, only a thousand volts nance effects toobtaina voltage of a'hunon open circuit, and--ye.t by means of resodred'thousand volts on the sending-conductor. It is possible to obtain resonance effects by use of a dynamo of'z low internal resistance, as. a portion, of asending conductor of large capacity .or self-induction, or both, having these electrical constants suitably proportioned so thatthe sending conductorhas a natural period identical that of the dynamo. This obviqusly renders the machine much cheaperitfo build and much easier to manipulate foi'isfignaling purposes than a dynamo or dynamo and transformer built to give one" hundred thousand volts directly. Second, the armature must be of low internal resistance, because if of a high resistance the oscillations will be dampened and high resonance voltages can not be produced. Third, it must be well ventilated, because during the perio fgsending a signal the current may run'u to liundiedsgor even thousands of amperes. Fourth, the length of wire in the armature must be as small as possible compared with the length of the sending-conductor, for otherwise tlie electricalconstants of the sendingcondu'etort'. a, of the circuit from the top of the conductor to the ground including the armature-will be determined too largely by tliat part of the circuit between the flI'IllfltllI'GtQfminals and the amount of radiation from the given voltage on the sending-conduct-dr would be much less thanwould be the case if the armature had relatively lesser length of wire. -In other words, the self induction and capacity of the armature must be as small a fraction as possible of the self-induction and capacity of the sending-conductor. When the dynamo is said to be in resonance with the sending-conductor, it is meant thatthe natural period of the whole conductor, from the top of the conductor to the grou'nd including the armature, is the same-as the periodicity of the dynamo.-

rents in the conductor should be so proportioned and distributed as not to effect the shape of the curve of voltage or to cause loss of power by hysteresis, as in suchcase there would be too 'much dampening. For these reasons the dynamo may be constructed with a fixed-armature containing no iron,

having the air-gap as long as possible consistvolving pole-pieces so shaped as to produce sine-waves as closely as possible, and the revolving parts formed of magnetic material of high tensile strength, such as nickel-steel.

A dynamo with the revolving part having a high peripheral speed of one-halfmile per minute has given ten thousand periods per second, and with a revolving part formed'of nickel-steela peripheral speed of five miles per minute can be safely maintained, giving thereby one hundred thousand periods per second. Such peripheral speed can be obtained by the employment of steam-turbine.

.It will be evident to those skilled in the Fifth, a is also essential that all iron magnetically influenced by curr u;

ent with a high magnetic fifix density, re-

art that instead of using a dynamo givinga thousand volts a dynamo giving aqhu'ndred volts may be used with-atransformer step-.

ping up to athousand volts; but in such case the length of wire in the secondary of the transformer shouldhave the same relation to the length of the whole conductor, including the secondary of the transformer, as-stated in reference Zto'a dynamo giving a thousand volts.

The best results are obtained when the fre- "quency of the source of alternatingvoltage,

as a dynamo, is equal or approximately equal to the natural frequency of the radiating-system. Thea'djustmen-tof frequencies'can be eifected by changing the speed oftl:ie dyna- "mo, The reason why the best results are obtained when the frequency of the dynamo or its equivalent (as a transformer connected to a dynamo) is equal or approximately equal to that of the natural frequency of the radiating circuit is that when the frequency of the dynamo-is less than this the chief effects are electrostaticand magnetic in their nature I that if otherwise the circuit would be a poor radiator.

and there is practically no electromagnetic radiation. Under these circumstances sig nals cannot be transmitted to anygreat distance, as the electrostatic and. magnetic effects fall 01f as a high power ofthe distance. As the frequency of thedy-namo is increased the efiects of electrostatic. and 'magneticinduction continue to predominate until the frequency of the dynamo approaches that of the sending-conductor. When this point is reached, if the radiating portion of the sending-conductor has a length which is a large fraction of the total length of the circuit a .large amount of energy can be radiatedin the form of electromagnetic waves and signals be transmitted a long distance. The

reason why the length of the radiating portion of the sending; conductor should be a large fraction of the total length-of the circuit is If, for example, the length .of the radiating portion of the sending-conductor is five feet and the length of the wire in the armature is five miles, the amount of energy radiated would be very small; compared to what it would be if the lengthhf wire in the armature were only five hundred feet and the radiating portion of the sending-conductor five feet. A further advantage incident to the employment of low frequencies is the fact that there is, as I have discovered, less absorption of the electromagnetic force as the waves travel along the ground than when the waves have high frequencies;

In the form of apparatus shown in .Fig. l

the generator 3 (in this case'a dynamo yhas one ,pole connected to ground and the other pole connected. by'a wire havirig-aninductance 2fto the radiating portion 1. "The sending-conductor which may have its radiating portion of any suitable form,- but preferably that shown in either Figs. 3 and 5, has its 'capacity or self-induction, or both, adjusted in the manner described, that the electromagnetic waves radiated will have low frequency.

At the receiving-station the receiving conductor 10 is connected tov one terminal of a 'translatingdevi'ee 11, as a telephone, the

opposite terminal thereof-being connected to the ground. As the frequencies of the waves which'induce currents in the conductor 10 are low, the diaphragm of the telephone will respond thereto, and the-vibrations of the diaphragm will produce audible notes.

.In Fig. 2 is shown another form of receiving apparatus. 'A portion of the ground connection of the receivingconductor 10 is formed by a piece of. fine wire '12, held in tension between the poles of a magnet 13. By the interaction between the currents passing along the wire 12 and the magnetic 'field the wire is caused to vibrate and make and break contact with the microphonic contactpoint.

14, which is so adjusted as to benormally out of contact with the wire 12. A circuit, including a'battery- 15 and" relay 16 or other translating device,- is formed in part by-the contactH and'the wire 12; so that whenever the secondary circuit is.comple ted by the vibration of the wire the relay will be'energized 7 J" If the radiating portion be, made, as shown in Fig. 5, with varying. superficial -d imensions-'e. g.,-with a swellor enlargement 17- the electromagnetic 'wavesgenerated from its diiierent surfaces will have diiferent periodicities, as the periodicity of electromagnetic waves depends, in part'at least, on the capacity of theradiating 'rtion at the sendingstation,- a 'similarly -j nstructed conductor may be used at the receiving-station, or two simple receiving-conductors suitably tuned maybe used.

By the use of a sending-conductor of large capacity and having that capacity uniformly distributed certain specific advantages are obtained which cannot be obtained by any other style of conductor. When the capacity is. not distributed with substantial-uniformity, it is impossible to obtain a sine form of electromagnetic wave, and this-form of wave. gives very much better results in thatitpermits of the'voltage being increased'by resonance to any extent, depending only on the resistance losses. For example, if the resistance belowit is possible .withan; impressed voltage of, say, five to reach a resonant voltage of two hundred or more with a capacity V distributed uniformlyi. 8. ,with a sine-wave,

give, a parabolic wave with a voltage of five, it is not possible to obtain by, resonance a higher voltage. than. twenty-five, since when while if the capacity be distributed, so as to 2 1111.6 p y is ge the resistance is also low'.-;' a

on account of the fact that the currents with these high frequencies flow over the surface of the sending-conductor it followsthat with a sending -conductor of large capacitynni formly distributed it is possible to get a sinewave and alow resistance-73.. e;., conditions necessary and favorable for the production of large resonant voltages from small impressed voltages, and hence conditions which permit of sending over longerd'istances than if the sending-conductor were of large capacity not uniformly distributed or of small ca pacity uniformly-distributed. By the term large capacity as herein used is-meant a capacity largeas compared with the capacities of wires heretofore, commonly used in the,

art, and by the term F uniformly distributed is meant distributed with substantial uniformity overthe radiating portion.

The, eflect oflocally increasing the super- 7 ficial area of the sending-conductor or of 10- cally increasing the capacity by any other suitable means is to produce two or more sets of waves of diiferent periodicities, the .peri

odicity of the first being dependent upon the electrical constants of the sending-conductor as a whole and the periodicity of the other depending upon the position and amount of localized increase of capacityin the same way as byattaching a weight or spring to apianos wire between its extremities additional vibrations in the wire are created By the term electromagnetic waves as used herein is meant waves of a Wave length long imeomparison with the wave length of what are commonly called heat-waves or radiant heat. By grounded conductor is meant a conductor grounded either directly or through a capacity, an inductance, or a resistance, so that the current in the conductor flows through the conductor to ground, and vice versa, when 'electromagnetic'waves are generated. The terms tuned and resonant are used herein as This invention involves the discovery of the desirability and practicability of using radiant electromagnetic waves of a frequency lower than has heretofore been recognized as desirable or practicable and in the devising j of a considerable number'ofvery meritorious and radiating waves of the higher and more, usual frequencies, and these are hereinafter- In order, therefore, to radiate large amounts features combined in an apparatus or system whereby the energy of. such :waves may be successfully radiated in quantities suflicient I for practical useover; long distances.

In constructingan apparatus that will give practical results with such low-frequency waves novel features have been devised, some 7 of which are" of general utility in generating claimed in terms'whieh\will cover the use thereof in other than the specific connection for which they are primarily intended;

The amount of radiation possible fora given systemis dependent,am ong other things, upon' the frequency, and, othgr thingsbeing equal,- the amount is lessfort e lower frequencies,

of energy by low-frequency waves, I take advantage of the rise ofvoltage due to resonance efieets brought aboutby a proper proportioning of inductance and capacity, so that the one including the phases of the impressed electro notive force and the current coincide in time.

Resonance eifects in a vertical conductor grounded at one end depend upon the quantities of the conductor which make it a good oscillator, and this is measured by the amount that the resistance is less than the square root of four times the inductance dividedby the capacitythat is, the amount of R is less than but in such aconductortlie best conditions of resonant oscillation require that the length of conductor be ode-fourth the length of the fundamental wave oscillating therein. It is evident then that if the conductor be a plainwire of ordinary size and the capacity and inductance employed for tuning be small the wave length therein will be substantially the length in the ether of,a wave of the same frequency, which-for 1 a frequency of ninety thousand is two miles,

andthe resistance which acts to cut down pacity multiplied by the square. root of the inductance-that is, inversely asthe quantity or value L C. Now since the condition of resonance is'that C L 00 :1 it is evident that instead of -increasing L and (l in equal proportions to get a'large total 1/ I, C

necessary fora good ,oscillator one'of these which is bad, as shown,.while increase of ca-p pacity in accordance with my invention is advantageous m manyways', as will be pointed out. I therefore make the capacity large and the induction correspondingly small, thereby making the quantity I, (1 large and corres pondingly shortening my sending-conductor and greatly reducing my resistance.

a The large-capacity I distribute uniformly over substantially all of the radiating portion of the conductor, thereby-further reducing instead of in creasing the resistan ce an d at the same timeproviding a large effective radiating-surface. Thefurther reason why thecapacity is thus distributed is that with any other arrangement it is diflicult to get a pure sine form of electromagnetic wave, because ducetwoor more sets of waves of difiepent periodicities.

. .factors,may be increased, while the other remains constant or is decreased. Large induct- 1 1cance,however,would1nvolve largereslstance, a

' any local increase of capacity tends .to pro- In order. that I may radiate large amounts cult to construct a low-frequency radiatingconductor which would be so largea fraction of the length of the whole sending-conductor.

From the above it will be seen that by my invention the internal current losses due to ohmic resistance are largely decreased by I using large total capacity and small inductance for the tuning, thereby shortening the length of sending-conductor necessary for a given frequency or fora given wave length in the ether. The shortening of the sending-conductor also facilitates the use of a radiatingconductor whichis a large fraction of the wave length. .The distribution of the capacity makes possible a better form of wave, decreases the resistance of that'part of the sending conductor, and further increases the radiating-surface;

.With this .system, .whereby large amounts of energy may be radiated at alow frequency,

- lam age to substitute for the induction-coil and s ark-gap now'in use a dynamo orsimilar source ofalternating voltage.

.If the dynamo be used without the sparkgap, I am able at once to produce a continu-' ous train of .IadiantwaVes of substantially 1 uniformstrength, as distinguished from the well-known systems wherein the sparledischarge starts a' train of waves of rapidly-diminishing power followed by relatively'long iutervals of no radiationl, Furthermore,

where the'spark discharge is used I am able, by reason of the persistent oscillation coupledwith the lowfrequency, to greatly diminish and, indeed,- to completely bridge over the intervals of no radiation, for with ten thou-. sand sparks perseeond exciting a sending conductor of a periodicity of ninety thousand I it is evident that if each spark gives only ten distances. v v V.

, From the aboveit will-be seen that by keeps oscillations before ,being damped sufliciently to stop radiationevery tenth voscillation will coincide with the first oscillation produced;

by the next succeeding spark. Thustheradiation will be practically continuous, and the total .energy of the first oscillationproduced bythe'spark will be'divid'ed between" only nine electromagnetic waves Now if. the, frequency were one million-and the" sparks ten thousand per second it would be necessary'tohave an oscillatorcapable of one 3 hundred useful oscillations of a power suffi-g cient to produc'eruseful-radiations.in order to maintain practically continuou s-radiation; The energygof' a s'inglespark in that case would be divided between one hundred radiant electromagnetic waves and would be too small for practical use over commercial in g R small and the frequenpy low I am able to radiate practically continuous streams of eloctromagnetic'waves of an energy sufficient for practically continuous effects at the re-' ceiving station. Even in the case where the sets of oscillations do not quite overlap in time it is evident that the intervals of inactivity are decreased by the increase of the tlIllfiOf a train to ten times what it would be with afrequency of .one million; This is a great advantage in cases where the receiver is tuned to the. period of the transmitter, for the regularity, continuity, and'great energy of the waves improve the resonance in a manner that by use of proper-devices at the receiving-station more than compensates for the rather broad curveof resonance involved in any use of large capacity for tuningpurposes.

I In practice it is found that substantial uniformity of distribution of capacity may be obtained by making the conductor uniform in figure from the top to a point at or near the bottom, asis indicated in Fig. 3. It has been held by some that the capacity of the upper portion of a vertical conductor of uniform cross-section'is much smaller than that of the with respect to ground is mainly dependent upon its size andshape and not upon'its disiniddle or' lower portions by reason of its greater distance from ground; but'I havefgg tance from the ground when the distance be- 7 tween the conductor and ground-is not small.

v I claim herein as my invention- 1. A sendin -conductor for'electromagnetic "waves, having a large capacity distributed with substantial"uniformity over its zradiat:

iing portion ,s'ubstantially as set forth.

2, A sending-conductor for electromagnetic waves, having its capacity'so adjustedmhat the waves radiated. therefrom have a low fre;

quency, substantially as set forth.

III)

3. Asending-conductorforelectromagnetic waves, havingits capacity and inductance so adj usted that the wavesradiated therefrom have a low frequency, substantially as set forth.

4. In a system for transmission of energy-by electromagnetic Waves, the combination of a source of alternating voltage and a conductor in series therewith forming a sending-con ductor said sending-conductor being adapted to radiate electromagnetic waves and having its radiating portion. of a length which isa large fraction of the quarter-wave length pro.-

duced by the alternating source 'in' the mediuin surrounding theradiating portlon, substantially asset forth. v.

' V Y 5.111 a system for transmission of energyby electromagnetic waves, the combination of a Source of alternating voltage and a cond uetor in series therewith forming a sending-conductor said sending-jconductor'beingadapted 1 to radiate electromagnetic waves having its l' I l radiating portion of alength which is a large fraction of the length of the sending conductor, substantially as set forth. q

6. In a system fortransmission of energy by electromagnetic waves, the combination of a source of alternating voltage generating groups of impulses of low frequency and a conductor in series therewith forming. a sending-conductor said sending-conductor being adapted and proportioned to radiate electromagnetic waves, and being tuned to the source of alternating voltage, substantially as 7 set forth. 7 o

7. In asystem for the transmission of energy by electromagnetic waves, the combination of an alternating-current dynamo and a conductor in series therewith forming a sendingconductor said sending-conductor being tuned to the dynamo and adapted to radiate electromagnetic waves, substantially as set forth.

8. In a system for the transmission of energy by electroma netic waves, the combination of a send ing-co ductor so proportioned as to radiate waves of low frequency and an alternating-current dynamo having its terminals connected respectively to the radiating portion of the sending-conductor and to ground, the dynamo being'so adjusted that its periodicityis the same or approximately the same as the natural period of the sending-conductor, substantially-as set 'forth. 3

9. A sending-conductor forelectromagnetic, wages, formed by an alternating-current dynamo and a conductor in series therewith, one pole 'of the dynamo being grounded, the sending-conductor thus formed being so proportioned as to radiate waves of low fre 45. r ground, the voltage-generator being so adqnency, substantially as set forth. '10.-A sending-conductor for electromagnetic waves so proportioned as. to radiate waves of low-frequency in combination with a source of alternating voltage having its terminals connected respectively to the radiating portion of the sending-00nd uctor and to justed that its periodicity is the same or approximately the same as the natural period of the system when so connected, substantially as set forth. r V

11. A sending-conductor. for electromagnetic waves, formed by a sd'urcefor continu-- ously generating alternating voltage and a conductor in series therewith, one pole of the source of alternating voltage beinggrounded,

. the sending-conductor thus formed being so proportioned as to'radiate waves of low frequency, substantially asset forth.

12. A system for signaling by electromagnetic waves having in combination a con-' ductor adapted to radiate waves of low frequency, anda receiver dependentfor itsaction upon a constant or independently-varying-magnetic field and adapted to respond to currents produced by said waves, substantially as set forth. I

13. A sending-conductor for electromagnetic .waves of a length much less than a quarter of the length of an ether-wave, having-a frequency equal to the natural periodof said sending-conductor, and having a radiating portion which is a large fraction of its total length. 14. A sending-conductor for electromagnetic waves having'a natural period of vibration much lower than the period of an ether-wave four times its length, whereby its radiating portion maybe a relatively large fraction of the total length of said sendingconductor. p

15. A sending-conductor for electromagnetic waves tuned to a desired, low frequency by large capacity and small inductance.

16. A sending-conductor-for electromagnetic waves having small inductance and tuned to a desired low frequency bya suitably-proportioned large capacity. 7 v 17. A sending-conductor for electromagnetic waves having low resistance, small selfinduction and great capacity, substantially as and for the purpose set forth.

18'. A sending-conductor for eleetromag' netic waves having low resistance, small selfinduction and great capacity so correlated as to support persistent oscillation of afrequency much less than that of an ether-wave of a; length four times that ofsaid sending- 1 conductor.

- 19. A system for transmission ofenergyby electromagneticwaves in combination with a radiating-conductor and a source of alternating electrical energy or potential, said radiatingconductor and source being coordinated and relatively adjusted toradiate a substantially continuous stream of electromagnetic waves.

ICO

20. A system of transmission of energy by electromagnetic waves including in combination a radiating-conductor and a source of alternating electrical energy or potential, saidradiating-conductor and source beingcoordinated and relatively adjusted to generate and radiate a substantially continuous stream of I electromagnetic waves.

21. A systemfor transmission of energy by electromagnetic waves, including in combinaating portion, said large capacity radiating portion being formed by a single continuous conductor of large area and substantially uniform cross-sectional or peripheral dimensions,

substantially as set forth.

23. In a system for the transmission of en ergy by'electromagnetic waves, a conductor grounded at one end l only, said conductor comprising a portion of a length which is equal to a large fraction of the quarter length in the surrounding medium of a wave having the same time-period as the natural or free period of said grounded conductor,said portion being composed of a single continuous conductor of an area great as compared with that of a wire of equal length, said area being distributed with substantial uniformity and equality throughout the length of said portion, substantially as set forth.

24. In a system for the transmission of en-' 'ergy by electromagnetic waves, a conductor grounded at one end only and having a pertion comprising a large fraetionof its total I5 length, composed of a single continuous conducting-surface of an area great as compared with that of a wire of equal length, said area being distributed with substantial uniformity and equality throughout the entire length of 20 said portion, substantially as set forth.

In testimony whereof I have hereunto signed my name.

' REGINALD A. FESSENDEN.

Witnesses:

'O. A. LONGFELLOW',

WM. H. DE LAcY.

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