The Effect Of Statics On Wireless Transmission

Wednesday, January 1, 1919
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connected with its terminals to groinnl :intl IHIIUHYY. l9l9 ELECTRICAL EXPERIMENTER 627 \ ._ ;\-> - sr? ',j _{`\" ` V /yi \ “ . / / " . .i...-.g ' k _ I Aiffffii, . ~ ‘ -~ '-f'-° ' . ; =-'rr H _A , The Effect of Statics on Transmission FEW statements regarding these phenomena, in response to a request of the Ececnucai. Exrekmcnran, may be useful at the present time in view of the in- creasing interest and importance of the subject. The commercial application of the art has led to the construction of larg- er transmitters and multiplication of their number, great- er distances had to be covered and it became imperative to employ receiving de- vices of ever increas- ing sensitiveness. All these and other changes have co- operated in empha- sizing the trouble and seriously im- pairing the reliability and value of the plants. To such a degree has this been the case that con- servative business men and financiers have come to look upon this method of conveying intelli- gence as one offer- ing but very limiterl .-_Q ' ,A By NIKOLA TESLA sisted of a transmitter comprising a pri mary circuit excited from an alternator or equivalent source of electrical energy and a high potential secondary resonant circuit ;;; i »_, f r s- . _ . .c, v- “" 'f Wireless nature of the effects, are making install- ments so defective in construction and mode of operation as to preclude the pos- sibility of the great realization which might be brought within easy reach by proper application of the ' underlying rinciples and one ofwhich- the most desirable at present-is the com- plete elimination of all static and other interference. During the past few years several ~ emphatic announce- ments have been rnade that a perfect solution of this problem had been discovered, but it was manifest from .- a casual perusal of these publications that the experts = were ignoring cer- tain truths of vital bearing on the ques- tion, and so long as .v,..;_,. __ . Written for the ELECTRICAL EXPERIMENTER 'JVJ t W. . V , , .. '-» it - _ r V ' _ . 1 _ i c r v is 1 H ‘»¢\ f Sw ‘f 5” 1 /' . r ` _,; fl -_ "¥f>_}i'.» ;~ it Ji Tu|a'| Stltlc Ellmln I Fully one possibilities, and the Government has deem- ed it advisable to assume control. This unfortunate state of affairs, fatal to enlist- ment of capital and healthful competitive development, could have been _avoided had electricians not remained to this day under the spell of a delusive theory and had the practical exploiters of this advance not per- mitted enterprise to outrun technical com- petence. _ _ With the publication of Dr. Heinrich Hertz's classical researches it was _an oh- vious inference that the dark rays_ investi- gated by him could be used for signalling purposes, as those of light in heliography, and the first steps in this direction were made with his apparatus which, in I896, was found capable of actuating receivers at a distance of a few miles. Three years prior to this, however, in lectures before the Franklin Institute and National Elec- tric Light Association, I had described a wireless system radically opposite to the Hertzian in principle inasmuch as it de- pended on currents conducted thru the earth instead of on radiations propagated thru the atmosphere, presumably in straight lines. The apparatus then outlined by me con- (fjt @ ,. to an elevated capacity, and a similar tuned receiving circuit including the operative de- vice. On that occasion I exprest myself confidently on the feasibility of Bashing in this manner not only signals to any ter- restrial distance but transmitting power in unlimited amounts for all sorts of industrial purposes. The discoveries made and experi- mental results attained I made with a wire- less power-plant erected in 1899, some of which were disclosed in the Century Maga- zine of June, 1900, and several U, S. patents subsequently granted to me have, I believe, borne-out strikingly my foresight. In the meantime the Hertzian arrangements were gradually modified, one feature after an- other being ahandoned, so that now not a vcstige of them can be found and my system of four tuned circuits has hecn uni- versally adopted, not only in its funda- mentals but in every detail as the “quench- ed sparks", "ticker’f, “tone wheel", high fre- quency and rotating field alternators, forms of discharges and mercury breaks, fre- quency changers, coils, condensers, regu- lating methods and devices, etc. This fact would give me supreme satisfaction were it not that the engineers, misinterpreting the tor, Patented and Used by Hlm over Twenty Years Ago. It Wlll Be rlbed In an Early Issue of the Electrlcal Experlmenter this was the case no such claim could be substantiated. I _- achieved early suc- cess by keeping the:- steadily in mind and :?pplyin§ my efforts rom t e outset in the right and correct scientific direction. I_may contribute to the clcarness of the subiect in answering a question which I liave been asked by the Editors of the l;LECTRICAL Exr'|mrMeN'ri-Lu with reference to the report contained in the last issue, that signals had been received around the globe. an achievement the practicability of which I_l;1ave fully demonstrated by experiment eig teen years ago. The question is, how can Hertz waves be conveyed to such a distance in view of the curvature of the earth? A few words will be sufficient _to show the absurdity of the prevailing opinion propounded ln textbooks. We are living on a conducting globe sur- rounded by a thin layer of insulating air, above which is a rarefied and conducting atmosphere. If the earth is represented by a sphere of lZ%" radius, then the layer which may be considered insulating for high frequency currents of great tension is less than l/64 of an inch thick. It is held that the Hertz waves, emanating from a trans- mitter, get to the distant receiver by suc- cessive reflections. The utter impossibility of this will be evident when it is shown by a simple calculation that the amount of (Continued on page 658)

ELECTRICAL EXPERIMENTER January. I9 l 9 THE EFFECT OF STATICS ON WIRELESS TRANSMISSION. (Continued from page 627) energyfeeeived, even if it _could be inl- lected in its totality, is infinitesimal and would not actuate the most sensitive instru- ment known were it magnified many million times. The fact is these waves have no per- ceptible influence on a receiver if situated ut n nmch snmller tlislanee, It should he remembered, moreover, thnt since the first attempts the wave lengths have been in- creased until those advocated by me were adopted, in which this form of radiation has been reduced to one-billionth. When a circuit, connected to ground and to an elevated capacity oscillates, two effects separate and distinct are groduced; Hertz waves are radiated in a irection at right angles to the axis of symmetry of the con- ductor, und _rifmallanzoutrly a current is /famed through ilu- earth. The former propagates with the speed of light, the lat- ter with a velocity proportionate to the coseeant of an angle which from the origin to the opposite point of the globe varies from zero to 180°. Expressed in words, at the start the speed is infinite and dimin- ishes, first rapidly and then slowly until a quadrant is traversed when the eurrcnt pro- ceeds with the speed of light. From that region on the velocity gradually increases, becoming infinite at the opposite point of the globe. `In a patent granted to me in April, 1905, I have summed up this law of propagation in the statement that the pro- jections of all half waves on the axis of symmetry of movement are equal, which means that the successive half waves, tho of different length, cover exactly the same area. In the near lulnre many wmulerfnl results will be obtained by taking advantage of this fact. There is a vast difference between these two forms of wave movement in their bear- ing on the transmission. The Hertz waves represent energy which is radiated and un- recoverable. The curreutenergy, on the other hand, is preserved and can be re- covered theoretieall , at least, in its entirety. If the experts will tiiee themselves from the illusions under which they are IaborinS, they will find that to overcome static dis- turbances all that is needed is a properly constructed transmitter and receiver with- out any additional devices or preventives. I have, however, devised several forms of apparatus eliminating statics even in the present defective wireless installations in which they are magnified many times. Such a form of instrument which I have used successfully is shown in the annexed photograph. These phenomena have been studied by me for a number of years and I have found that there are nine or ten different causes tendingl to intensify them, and in due course I s all give a full de- scription of the various improvements I have made, in the ELECTRICAL Execut- Mewren, For the present I would only point out that in order to perfectly eliminate the static interference, it is indispensable to redesign the whole wireless apparatus as now employed. The sooner this is under- stood the better it will be for the further evolution of the Art.