The True Wireless

Thursday, May 1, 1919
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30 resulting in the generation of heat as in tl1e incandescent lamp. Theoretically consid- ered, the efficiency of conversion of energy should he the same in both cases. Granted, then, that an ecnninnic system of power translnission thru a single wire is 72s/nfs four c/rcu/f B tu/nd mr;/es: .9/J-ka: ‘ /_\ A A ,;i§5.;_ ` ct ii t . C _ `_ Q ,` ‘~,>;§¥“*,,'_. \ » -- ._ ' _ I D& QC §|. - W Q , ,._.,, __ G _ _ ‘ < .----. i- . /fe/'/zM7v¢.9/:fe/71 l v , J d I III I =..»= ¢|i 4 . ||t' ‘lllllllllltlll E E TesIa's Four Ctrcult Tuned System Con. trasted Wlth the Contemporaneous Hertz. wave System. Flg. 11. practicable, the question arises how to col- lect the energy in the receivers, With this object attention is called to Fig, 5, in which a conductor is shown excited hy an oscil- lator joined to it at one end. lividently, as the periodic impulses pass tl\ru the \vire, differences of potential will he created along the same as well as at right angles to it in the surrounding ineditnn and either of these may be usefully applied. Tlnis at a, a circuit comprising an indnctanec and ca- pacity is resonantly excited in the trans- verse, and at b, in the longitudinal sense. At C, energy is collected in a circuit parallel to the conductor but not in contact with it, and again at d, in a circuit which is partly sunk into the conductor and may hc, or not, electrically connected to the same. lt is important to keep these typical disposi- tions in mind, for however the distant ac- rmm.///ng c/mf# nw... of rmfving of../ir.. M1 ' '._-. - . ._t.-,,-.. rmnwmhq mu./v - C- y wnnfdu m /wapwhf: ",§f,(§Q§'j,,_,§f,"f,,,, vt'/f/' 9/W”-f orbofh fm _= i ; T A sam, af /1.9/» ffequmy tl/I/‘ln/.1 __ ;_. Arraniements of Dlrectlve Clrcults Descrl ed In Tesla's U. S. Patent No. 613.809 of November 8. I89B, on "Method of and Apparatus for Con- trolling Mechanism of Moving Vu- lell Dr Vshlclbl." Flq. 12. ELECTRICAL EXPERIMENTER tions of the oscillator might be modified thru the immense extent of the globe the principles involved are the same. Consider now the effect of such a C011- dnrtiir of vast tllnn-nsiinis on a circuit ex- citing it, 'I he upper diagram of Fig. 6 il- lustrates a familiar oscillating s 'stem com- prising a straight rod of self-incluetance ZL \vitl\ small terminal capacities fc and a node in the center. ln the lower diagram of the Egure a large capacity C is attached to the rod at one end \vith the result of shifting the node to the right, thru a distance cor- responding to si~lf-indnctance X. As both parts uf the system nn either side nf the node \-illrnte at the same rate, we have evi- dently, (L -l- X) c = (L - X) C from C _ which X = L --; When the ca- C -l- r pacity C hecoincs cnnnncnsnrate to that of the earth, X approximates L, i|1 other words, the node is close to the ground con- nection. Thr r,rui‘l 1i4'lrr1|iiuuIimi of il: /vosilinn ir wry ini/mr-lmil in Ihr mlrnln- lion of ver/uin lv1'rc_fIrinl rlcclrirul and grodrliz zlntn and I have devised special means with this purpose in view. l\'ly original plan of transmitting energy withnnt wires is shown in tlte upper dia- grznn of Fig. 7, while the lower one illus- trates its mechanical analog, first publisht in my article in the Century Magazine of _]unc, 1900. An alternator, preferably of high tension, has one of its terminals con- nected tn the ground and the other to an elevated capacity and impresses its oscil- latio|\s upon the earth. At a distant point a receiving circuit, likewise connected to ground and to an elevated capacity, collects some of the energy and actuates a suitable device. I suggested a multiplication of such units in order to intensify the effects, an idea which may yet prove valuable. In the analog two tuning forks are provided, one at the sending and the other at the re- ceiving station, each having attached to its lower prong a piston Fitting in a cylinder. The t\vo cylinders communicate with a large elastic reservoir filled with an incom- ,»::f¢'{i§f?*11~:- uj‘-if--';'.1---'"~~~:fI_‘~~it:f\ '.' »'/ .~ 1 ,' ,f' ,f .",f' . \_"._ ._ , I. /',' ,' ._ . . . . . / . 1 ‘ .;:::;i: 13,-tm; ~=sg¢;5 f»-»-fm a\=\i==| ..,..........,;, ..a,;,:,,._,,,,, Dlagram Exposlng the Fallacy of the Glldlng Wave Theory as Propounded In Wlreleu Text Books. Fig. 13. pressilvle fluid. The vibrations transmitted to either of thc tuning forks excite them by resonance and, thru electrical contacts or otherwise, bring about the desired re- sult. 'Ihis, I may say, was not a mere mechanical illustration, but a simple rep- resentation of my apparatus for submarine signaling, perfected by me in 1892, but not appreciated at that time, altho more eth- cient than the instruments now in use. The electric diagram in Fig. 7, which was reproduced from my lecture, was meant only for the exposition of the prin- ciple. The arrangement, as I described it in detail, is shown in Fig. 8. ln this case an alternator energizes the primary of a transformer, the high tension secondary of which is connected to the ground and an elevated capacity and tuned to the imprest oscillations. The receiving circuit consists of an indnctance coititecterl to the grinnul and to an elevated terminal without break and is resrmantly responsive to the trans- mitted oscillations. A specific form of re- ceiviiig device \vas not mentioned, but I had m mind to transform the received cur- rents and thus make their volume and ten- sion suitable for any purpose. This, in May, l9l9 substance, is the system of today and I am not aware of a single authenticated in- stance of successful transmission at con- siderable distance by ditierent instrumen- talities. It rn-ight, perhaps, not be clear to t.,/f.-U I .` /__ / Q line! lL”~40f7¢4Qll ' ' 1 ' ' V ~ .,.\ ,$s,_, ._ ---__`\‘:\‘\ ///ff" _--- \(,__Z;~1::c‘ f»,c;I:;I` ,f ,-;:-13s 231;;1- \ / /)\ » . ~\/\`\ \ I / r >S< ` \ \ \ 1 , ,I , yo, \ \ t I 1 1 \ \ \ \ \ 1 1 1 r \ \ \ \ / / 1 ' \ \ \ \ \ 1 / . / i ‘_ \, \, \ I I v I 1 I ' *ff \ t \ : l Fl¢1.14. Dlagram Explalnlng the Re- lat on Between the Effactlve and the Mealured Current In the Antenna. those who have perused my first descrip- tion of these improvements that, besides making known new and etlicient types of apparatus, I gave to the world a wireless slystem of potentialities far beyond any- tiing before conceived. I made explicit O Herb asc/7/q/o{;fqf’ , agfgla/br gnra/che/y ¢ 'Y W 'M /ng/.Ly er/‘¢¢i>if¢ i». ,. »..,... . - ~‘ - " i w- .. _ _ . . -_ _ : Flg. 15. Illultratlng One of the General Evl- dancea Against the pace Wave Tranlmlnlon. and repeated statements that I contem- plated transmission, absolutely unlimited as to terrestrial distance and amount of en- ergy. But, altho I have overcome all ob- stacles which seemed in the beginning un- surmountable and found elegant solutions of all the problems which confronted me, yet, even at this very day, the majority of experts are still blind to the possibilities which are within easy attainment. My confidence that a signal could ‘be easily Hashed around the globe was strengthened thru the discovery of the "ro- latin? brush," a wonderful phenomenon whicl I have fully described in my address before the Institution of Electrical Engi- neers, London, in 1892, and which is illus- trated in Fig. 9. This is undoubtedly the most delicate \vireless detector known, but for a long time it was hard to produce and to maintain in the sensitive state. These difficulties do not exist now and I am look- ing to valuable applications of this device, particularly in connection with the high- speed photographic method, which I sug- gested, in wireless, as well as in wire, trans- mission. Possibly the most important advances dur- ing the following three or four years were my system of concatenated tuned circuits fhv hm afprwmdad arm//is eqt/adv :lm-/ive. 17|/um///cr fmnsmf?/¢ru firewire/- 'r -xt -:.::' 1;-"': -'-e- FIU. 19. Showing Unlmportnnce of Relative Pnultton ul Trmumlttlnu and Roculvlng An- tennae In Dllprovul nt tha Hurt:-wave Theory. and methods of regulation, now universally adopted. The intimate bearing of these in- ventions on the development of the wireless art will appear _from Fig. 10, which illus- (Continued an page 61)

May, l9l9 7.-»»..~m, in ¢,sratt»rs :uid elm-rtrlrnl ns- cllalors had first to he produced. 'l`l\e energy of these had to be transformed in effective transmitters and collected at a distance in proper receivers. Such a sys- tem would he manifestly circumscribed in its usefulness if all extraneous interfer- ence were not prevented and exclusiveness secured, lu time, however, 1 recognized that devices of this kind, to he most etlcct- [lmz/zd mpvc/y E/eva/¢d //hmalor Pea/i/er _ = :”" frunsm/7/er Awe/ifer Tranlmlulen of Electrlcal Energy Thru the Earth as Illustrated In Te|la'e Lecture: Be- fore the Franklln lnltltute and Elcctrlc Llght Auoclatlon In Februar and March, 1893, and Mechanical Analog olv the Same. Flg. 1. ive and cllicient, should he designed with due regard to the physical properties of thu _planet and the electrical conditions obtaining on the same. l will hrielly touch upon the salient advances as they were made in the gradual development of the system. _ _ lhe lugh frequency alternator employed tn my first demonstrations is illustrated in Hg. l. lt comprised a field ring, with 38-l pole projections and :x disc artuature with coils wound in one single layer which were connectetl in various ways according to rc- quirements. lt was an excellent nnicliinc for experimental purposes, furnishing sinn- sotdal currents of rom l0,(Xll) to 20,000 cycles per second. The output was com- paratively large, due to the fact that as much as 30 anipercs per square millimeter could be past thru the coils without injury. The diagram in Fig. 2 shows the circuit arrangements as used i|\ n\y lecture. Reso- nant conditions were ntaiutained hy tneans 29 r/.-.f.,/,J ramff, ,,M,,,, ,aww nfsumif atgmwff .mg tlfru/ f fm www/ Maw,/mn /"uct/ml wma-fy my/» frammdfar 5`“""'Wi`““" ,_ . it-< | a, - si , ‘\ '-‘amend ' - ~ :_ www Tesla's System of Wlreleu Transmlnlont Thru the Earth as Actually Exposed In Hll Lectures Before the Franklin In- itlluie and Electrlc Llght ASIOClat|0|'\ ln February and March, 1893, Flg. B. ot' a condenser subdivided into small sec- tions, the liner adjustments being elfected hy a niovalilc irnn core \vithin an induct- ance coil. Loosely Iiulted with the latter was a high tension secondary which was tuned to the primary. The operation of devices thru a single wire without return was puzzling at first because of its novelty, hut can be readily explained hy suitalile analogs. For this purpose reference -is made lo Figs. 3 and 4. In the former the low resistance electric conductors are represented hy pipes of large lllllllIllllllllllllllllIlllllllllllllllllllllllllllllllilll The Forerunnur of the Audlorh-»lh0 Melt Sensltlve Wlreleu Detector Known, as De- f’ scrlbed by Tolla ln HI: Lecture Before the lnatltutlon of Etectrtcat Eng|. neers.Lonaon, 1 February, tssz. i Flq. 9. IlllllllllllllllllllllllllllllllIllllllllllllllllllllllllllll _ " section, the alternator hy an piston and the filament ol an incandescent lamp hy a minute channel connecting the pipes, It will he clear from a glance at the diagram that very slight excursions ol' the piston would cause the lluid to rush with high ve- locity thru the _ rf \ A oscillating the reach of every young JYJTf"0f[NUflllfIlllllIDllKl|l5'.Y07|Mll(.lYl/A’lIN f[$`U3 ll S PAY!/VT I5~“|l7ll/.l`oflI£ll9(Alll lHW[MlU IN If//lil!!! THNSHISSION small channel and that vir- “’“?‘°‘“' .3 “ d /aww. ma...-/¢»¢ mnqainaensef tually all the which, tn a MMI,” ¢ y ¢¢ ; mmfss ¢ n ¢ r gy gf time “ig ‘dwg ,,,,,,,,,,,,, l l . . . . . 5 ur:/rn m 0 vcme nt tant wi ea .umdmn/,ur ,fu/assi./»¢~¢»4»<. 2= wo u 1 d be 3° 'undertalf 9 -=f~'- WWW t ransformed ings overs ia - med iw/v into heat b °VY\|'|8 “\ lllilli' °`9”“zi¥’?%“9' friction, simi P I Y “ d ¢ and @ the/1? gm/rn/,erm . HI @ larly to that importance all WMWMF/"UNM of the electric past acl;iev}e- mm o v » a n cfm/ _ w,-,-eng in ¢|1¢ ments o t e lamp filament. en ineer. Tl d 'lqlw pupulaf mfmwrv//fo c//:cu/rs arasovrauo/unsfrom souurfzv d;ag,i;,nsu€,';|| impression is inn". now be self- thatmywire- U-' ex 1 ¢ M' as _ _ P am* 9'-V' lf” “"?"k1%;’ . '/mu MMM" /9“'*>U"M‘ nmsmwawsf Corresponding egun in , _ns_¢1i»_q=qwfgur.¢?. I _ _ w .r/mf/Wy .emi (0 (bg m-mi, but 35 I mal' ”;‘ff”9°7'/’°”°"' mmowgfmfwh ”""*°’9"“”"”W nal capacity of ter of fact I N 9 "9 9 . a-aaamwme Q/mme ""”"“’9' "”"" t he electric spent the _two ,,,h,,a,b“,m}, 5 y 5 ; ¢ m an P 1' ¢ Q¢ I “ E J elastic reser- years tn tnves- v 0 i r is em. ti ations. em- | d ‘ p§,y;,,g fam, f//ECPFFESFUNP/A6/'91/Pft//VID(//?£'l//f50/`//rt`rY/RILISS srsrm gisgfnsef of apparatus, th ' ,,.,,,¢ uf whici, »M~,. »?;”»rW».,»Z] /ww /Nm., ,fa :‘§‘;°3§'tf' I _ 1 m¢»v>v4w - “ff//f /U/'fd ~'f~-/f//I/~»»/ff/-my /mf:-..¢.,.,t4~»..,,,, _ " ‘ W ff I' ¢ 3 “\°>l /v'i‘»i%/1 .wpyng - hswency ofmew/ I /mea mmf/ Lv sw//My pipe. As the ]|k¢ ghose of . om/ an or - uumf/no/nee//n¢s¢»i» /mea ~ _ _ ~ ,fs/my rw./sig _ ,¢.y.,»e¢/f¢9~ o u t by a Te|I|'l System ol Concltenated Tuned Clrculto Shown and Descrlhert ln U, S. Patent No. 568,178 of September 22. 1896, ard Corresponding Arrangements ln Wlreless Transnilsslon, thru lhe rc- stricted pas- sagewithgreat speed, this

28 ELECTRICAL EXPERIMENTER May, l9l9 (i l RADIQ DEPARTMENT Q( ) s o ioeless By NHKQLA 'H`E§LA Written Exclusively for The Eleclriral Experirnenlcr VER since the announcement of Maxwell's electro-magnetic theory scientific investigators all the world over had been bent on its experi- mental verification. They were con- vinced that it would be done and lived in an atmosphere of eager expectancy, un~ \ -a - Alternator of 10,000 Cycles p.s., Capaclty 10 K.w., Whlch was Employed by Tesla In Hls First Demonstratlons of High Frequency Phenomena Before the American Institute of Electrical Englneers at Colurnhla College, May 20, 1as|. Flq. 1. usually favorable to the reception of any evidence to this end. No wondcr then that the publication of Dr. Heinrich Hertz’s re- sults caused a thrill as had scarcely ever been experienced bc fore. At that time I was in the midst of press- ing work in connection with the commercial iutroiluctiou of my systcni of pnwcr trausluissisni, but, nevertheless, caught the lire of enthusiasm and fairly burned with desire to hclmld thc miracle with my uwn eyes. /\ccoriling- ly, as soon as I had freed myself of these imperative duties and resumed research work in my laboratory on Grand Street, New York, I began, parallel with high frequency alternators, the construction of several forms of apparatus with the object of ex- ploring the field opened up by Dr. Hertz. Recognizing the lim- itations of the

May, 1919 The True Wireless By Nikola Tesla g (Continued from page 30) trates an arrangement described in my U. S. Patent No. 568178 of September 22, 1896, and corresponding dispositions of wireless apparatus. The captions of the individual diagrams are thought sufficiently explicit to dispense \vith further comment. I will merely remark that in this early record, in addition to indicating how any number of resonant circuits may be linked and regu- lated, ‘I have shown the advantage of the proper timing of primary impulses and use of harmonics. In a farcical wireless suit in London, some engineers, reckless of their reputat-ion, have claimed that my circuits were not at all attuned; in fact they as- serted that I had looked upon resonance as a sort of wild and untamable beast! It will be of interest to compare my sys~ tem as first described in a Belgian patent of 1897 with the Hertz-wave system oi that period. The significant differences between them will be observed at a glance. The tirst enables us to transmit economically energy to any distance and is of 'inestiinahle value; the lztlter is capable of a raulius ul only n few luilcs and in worthless. ||\ the lirst then: are no spark-gaps and the actions are enormously maguilied by resonance. In both transmitter and receiver the currents are transformed and rendered more e|tec» tive and suitable for the operation uf any desired device. Properly constructed, my system is safe against static and other in- terference and the amount of energy which may be transmitted is billions of timr: greater than with the Hertzian which has none of these virtues, has never been used successfully and of which no trace can be found at present. A well-advertised expert gave out a state- ment in l899 that my apparatus did not work and that it would take 200 years he- fore a message would be flashed across the Atlantic and he even accepted stolidly my congratulations on n supposed rent feat. But stibsuqnexit examination of tie records showed that my devices were secretly used all the time and ever since I learned of this I have treated these Borgia-Medici methods with the contempt in which they are held by all fair-minded men. The wholesale appropriation of my inventions was, how- ever, not always without a diverting side. As an example to the point I may mention my oscillation transformer operating \vith an air gap. This was in turn replaced hy a carbon arc, q\|cncl1ctl gap, an atnlospltcre of hydrogen, argon or helium, by a me- chanical break \vith oppositely rotating members, a mercury interrupter or some kind of a vacuum hulh and by such tour: de farce as man new “systems" have been produced. I reflizr to this of course, with- out the slightest ill-feeling, let us advance by all means. But I cannot help thinking how much better it would have been if the ingenious men, who have originated these "systems," had 'invented something of t|\eir o\\'n instead of depending on me altogether. Before 1900 two most valuable improve- ments were made. One of these was my individualized system with transmitters emit- ting a wave-complex and receivers compris< ing separate tuned elements coiiperatively associated. The underlying principle can he explained in a few words. Suppose that there are n simple vibrations suitable for use in wireless transmission, the prolmahil- ity that any one tune \vill ble struck hy an- extraneous disturbance is -. There will then remain n-1 vibrations 'and tl\e chance that one of these will he excited is hence the prolmhilily that two tunes \\.iiiulil ELECTRICAL EXPERIMENTER 1 be struck at tl\e same time is »;. Sim- 1: in-l) ilarly, for a comlrinatiou of three the chance 1 will be _-» and so on. It will be n (n-1) tn-2) readily seen that in this manner any desired tlcgrcc of safet against the slntics or other lcintl of Llist|u'iiance can lic attained pro~ vided the receiving apparatus is so designed that 'its operation is possible only thru the joint action of all the tuned element.. This was a diilicult problem which I have suc- cessfully solved so that now any dcsirrd rmmber of simultaneous- 1ne_v.rnge.r is prac- ticable in the lr'anr1ui:.rifm I/rm (he earth as well as I/mt artificial coudnrlnrs. The other invention, of still greater 'im- portance, is a peculiar oscillator enabling the transmission of energy without wires in any quantity that may ever be required for iiulnstrial nsc, tn any tlistnncc, and with vcry lliglu economy. it was the outcome of years of systematic study and investiga- tion and wonders will be achieved by its ll\(‘i\l\F. 'l`lu: prevailing ||1isttu|\cc|mti<»|\oi thc nu~t‘l\- anism involved in the wireless transmis- sion lias been responsible for various unwarranted announcements which have misled the pulxlic and worked harm. By keeping steadily in mind t|\at the transmis- sion thru the earth is in every respect identical to that thru a straight wire, one \vill gain a clear understanding of the phe- nomena and will be able to judge correctly the merits of a new scheme. Without w-ish~ int: to detract from tl\e value of any plan that has been put forward l may say that the are devoid of novelty. So for instance in Fig. 12 arrangements of transmitting and receiving circuits are illustrated, which I have described in my U. S. Patent No. 613809 of November 8, 1898 on a Method of and Apparatus for Controlling Mechan- ism of Moving Vessels or Vehicles, and which have been recently dished up as orig- i|\al discoveries. In other patents and tech- nical publications I have suggested conduc- tors in the ground as one of the obvious modifications Ind-icated xn Fig. 5. For the same reason the statics are still the bane of the wireless. There is about as much virtue in the remedies recently proposed as in hair'restorers. A small and rnm/mr! npparantv lm: brrn /vraducrzl which |lnr.r'r|1t‘1I\' rulirrly will: thi.: lronlrlr, nt least in plants suitably ruxnotlcllud. Nothing is more important in the present phase of development of the wireless art than to dispose of the dominating erroneous ideas. With this object I shall advance a few arguments based on my own observa- tions 'wlnich prm/L' that Hertz '1un1JL'.r have little to do with the result: obtained even ut :mall distances. In Fig. 13 a transmitter is sho\vn radiat- ing space waves of considerable frequency. lt is generally lielicved that these waves pass along the earth’s surface and thus affect the receivers. I can hardly think of any- thing more improbable than this "gliding wave" theory and the conception of the “guided wireless" which are contrary to all laws of action and reaction. Why should these disturbances cling to zi conductor where they are connteracted hy induced cur- rents, when they can propagate i|\ all other directions unimpedctl? The fact is that the radiations of tlte transmitter passing along the eartl1's surface are soon extinguished, the he-ight_of.the inactive zone indicated in the diagram. being: some function of the wave length, the hulk of the waves travers- ing freely the atmosphere. Terrestrial phe- nomena which I have noted conclusively shnw that there is no Hrn'zri.\-irl¢' Inyrr, or if it exists, it is of no effect. It certainly \vould be unfortunate if the human race were thus 'imprisoned and forever without lmwer to reach out into the tlcnths of space. The actions at a distance cannot be pro- portionate to the height of the antenna and the current in the same. I shall endeavor to make this clear by reference to diagram in Fig, 14. The elevated terminal charged to a high potential induces an equal and opposite charge in the earth and there are thus lines giving an average current I : Qn which circulates locally and is useless except that it adds to the momen- tum. A relatively small number of lines q however, go off to great distance and to these corresponds a. mean current of if = Mm to which is due Ihr action at a distance. The total average current in the antenna is thus Im = 4Qn + 4qu and its intensity is no criterion for the performance. The . . . ‘1 electric eliicicncy of the antenna is -- _ _ Q + 11 and this is often a very small fraction. Dr. L. W. Austin and Mr. J. L. Hogan have made quantitative measurements which are valuable, but iar from supporting thc Hertz wave theory they are evidences in disproval of the same, aswill be easily per- ceived by taking the above facts into con- sideration. Dr. Austitfs researches arc es- pecially useful and instructive and I regret that I cannot agree with him on this subject. I do not think that if his receiver was af- fected by Hertz waves hc could ever estab- lish such relations as he has found, but he would be likely to reach these results if the Hertz waves were'in a large part eliminated. At great distance the space waves and the current waves are of equal energy, the former bein merely an accompanying man- ifestation og the latter in accordance \vith the fundamental teachings of Maxwell. lt occurs to me here to ask the question- why have the Hertz waves been reduced from the original frequencies to those I have advocated for my system, when in so doing the activity of the transmitting ap- paratus has been reduced a billion fold? I can invite any expert to perform an experiment such as is illustrated in Fig. 15, which shows the classical Hertz oscillator and my grounded transmitting circuit. It is a fact which ‘I have demonstrated that, altho we maly have in the Hertz oscillator an activity t ousands of times greater, the effect on the receiver is not to he compared to that of the grounded circuit. This shows that in the tran.rmi.i-.rion from an airplane we are merely warkivig thru a condenser, the caracity of which is a function of a lognrit unie ratio between the length of the conductor and the distance from the ground. The receiver is aliected -in exactly the same manner as from an ordinary transmitter, the only diference being that there is a eer- tain modification of the action which can be predetermined from the electrical constants. t ‘is not at all dillicult to maintain com- munication between an airplane and a station on the ground, on the contrary, the feat is very easy. To mention another experiment in sup- port of my view, I may refer to Fig. 16 in which two grounded circuits are shown excited by oscillations of the Hertzian order. It will be found that the antennas can be put out of parallelism without noticeable change in the action on the receiver, this provinz that it is due to currents propagated thru the ground and not to space waves. Particularly signihcant are the results ob- tained in cases illustrated -in Figures 17 and 18. In the former an obstacle is sho\vn in the path of the waves but unless the re- ceiver is within the eFiective eleclnnlalic influence of the mountain range, the signals are not appreciabl weakened hy the pres- ence of the latter, iiecause the currents pass under it and excite the circuit in the same way as if it were attached to an energized wire. If, as in Fig. 18, a second range hap- pens to he beyond the receiver, it could only strengthen the Hertz wave effect by reflec- tion, hut as a matter of fact it detracts (Canlinued an page 87)

May. 1919 | The True Wireless By Nikola Terla (Conlinued from page 63) greatly from the intensity of the received impulses because the electric niveau between the mountains is raised, as I have explained in connection with my lightning protector in the EXPERIMENTER of February. Dvumfwkr Ff¢1'W/' 1 - me->-_ -~e~ - =;,- Flg. 17. Illuxtratlng Influence of Obltacle In the Path of Tranemlulon ao Evidence Aqalnet the Hertz-wave Theory. Again in Fig. 19 two transmitting cir- cuits, one grounded directly and the other thru an air gap, are shown. It is A com- mon obsurvation that the fornter is far hmmm- Atwkr .1-L /i"_. u 4. 1 Flq. 18. Showlng Effect of Two Hllle an Further Proof A_lg:|nst the Hertz-wave eory. more effective, which could not be the case in a transmission with Hertz radiations. In like manner if t\vo grounded circuits are 7'/nnsm/7/¢r Ira/um//f¢I' euparulld Z/var/eyd bk,/,a,/, gm, brzak f/vm ground ’”'°" Flq. 19. Comparing the Actlonl of Two Form: of Transmitter as Bearlrtlg Out the Faltaey of the Hertz-wave henry. observed' from day to day the effect is found to increase greatly with the damp- ness of the ground, and for the same reason 7721/IJ/rgifla' W/M mql/ fcrmma/ adpac/5' Dvnsm/7/¢r mi'/1 We krmlnal capac ‘ _y Flu. 20. Dlaprnvlnq the Hertx-wave Theory by Two Transmltterl. One nf Great and the Olller ul Small El\Gl'qy. ELECTRICAL EXPERIMENTER also the transmission thru sea-water is more efficient. _ illuminating experiment is indicated tn_ Fig. 20 in which two grounded trans- mitters are shown, one with a large and thc other with a small terminal ca acity. Sup- pose that_ the latter he 1/10 oi] the former but _that it is charged to 10 times the po- tential and let the frequency of the two circuits and therefore the currents in both antennas be exactly the same. 'l`he circuit with the smaller capacity will then have 10 times the energy of the other but the effects on the receiver will be in no wise propor- tionate. The same conclusions will be reached by transmitting and receiving circuits \vith wires buried underground. In each use the actions carefully investigated will be found to be due to earth currents. Numer- ous other proofs might be cited which can be easil verified. So for example oscilla- lians o low frequency are ever so much more e ective in thc transmission which is inconsistent with the prevailing idea. l\ly observations in 1900 and the recent trans- missions of signals to very great distances are another emphatic disproval. The Hertz wave theory of wireless trans- mission may be kept up for a while, but I do not hesitate to sa l||nt in a shnrt time it will he recognizcil’:|s one ol lhu most remarkable and im-xplicable ubcrrutions ol the scientilic mind which has ever been rt:- cordcd in history.