USRE11913E - marconi - Google Patents

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USRE11913E
USRE11913E US RE11913 E USRE11913 E US RE11913E
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US
United States
Prior art keywords
circuit
tube
oscillations
powder
station
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English (en)
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Guglielmo Marconi
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By Mesne assignments
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  • WITNESSES INVENTOR Qughdm o Mtwconi
  • Threadneedle street, London, England have invented certain new and useful Improvements in Transmitting Electrical Impulses and Signals and in Apparatus Therefor, of which the following is a specification.
  • Hertz rays or Hertzoscillations All line-wires may be dispensed with.
  • All line-wires may be dispensed with.
  • At the transmitting-station I preferably employ aRuhmkorff coil having in its primary circuit a Morse key or other signal; ing instrument and at its poles appliances for producing the desired oscillations.
  • the Ruhmkorit coil may, however, be replaced by any other source of high-tension electricity. When workin g with large amounts of energy, it is, however, better to keep the coil or transformer constantly working for the time during which one is transmitting, and instead of interrupting the current of the primary interrupting the discharge of the secondary.
  • the contacts of the key should be immersed in oil, as otherwise, owing to the length of the spark, the current will continue to pass after the contacts have been separated.
  • a local-battery circuit containing any ordinary receiving instrument and an appliance for closing the circuit, the latter being actuated by the oscillations from the transmitting-station.
  • Figure 1 is a diagrammatic front elevation of the instruments at the transmitting-station when signaling through the air
  • Fig. 2 is a vertical section of the transmitter.
  • Fig. 2 is a longitudinal section of the oscillator to a larger scale.
  • Fig. 3 shows a detail of the trembler-break on a larger scale.
  • Fig. 4 isa diagrammatic front elevation of the instruments at the receiving-station.
  • Fig. 5 is an enlarged view of the receiver.
  • Fig. 6 shows a modification of the tube j.
  • Fig. '7 shows the detector.
  • Fig.8 is a full-sized view of the liquid resistance.
  • Figs. 9 and 10 show modifications of the arrangements at the transmitting-station.
  • Fig. 11 shows a modification of the arrangements at the receivingstation. 7 r
  • a is a battery
  • b an ordinary Morse key closing the circuit through the primary of a Ruhmkorlf coil 0.
  • the terminals 0' of the secondary circuit. of the coil are connected to two metallic balls 0? d, fixed by heat or otherwise at the ends of tubes d d, Fig. 2, of insulating material, such as ebonite or vnlcanite.
  • e e are similar balls fixed in the other ends of the tubes (1'.
  • the tubes d fit tightly in a similar tube d, having covers (1 through which pass rods d, connecting the balls d to the conductors.
  • One (or both) of the rods d is connected to the ball d by a ball-and-socket joint and has a screw-head upon it working in a nut in the cover (i By turning the rod, therefore, the distance of the balls e apart can be adjusted.
  • d? represents holes in the tube d, through which Vaseline, oil, or like material is introduced into the space between the balls e.
  • the balls (1 and e are preferably of solid brass or copper, and the distance they should be apart depends on the quantity and electromotive force of the electricity employed, the eifect increasing with the distance so long as the discharge passes freely.
  • the distance between 2 and e should, to assure good results, be from one twenty-fifth to one-thirtiet-h of an inch and the distance between dand e about one and one-half inches.
  • spark-gap between the central balls of the oscillator it is preferable to divide the spark-gap between the central balls of the oscillator into several smaller gaps in series, This may be done by introducing between the big balls smaller ones of about half an inch diameter, held in position by ebonite frames.
  • g is the battery
  • h a tele-- graphic instrument onthe derived circuit of a relay '11,.
  • the appliance I employ as a circuit-closer is shown at Fig. 5, and consists of a glass tubej, containing metallic powder or grains of metal j, each end of the column of powder or like material. Two short piecesj prefer-.
  • the tube j is one and one-half inches long and one-tenth or one-twelfth of an inch in internal diameter.
  • The-length of the stopsj is about one-fifth of an inch, and the distance between the stops is about onethirtieth of an inch. I find that the smaller the space between the stops in the tube the more sensitive it proves; but the space cannot under ordinary circumstances be excessively shortened without injuring the fidelity of the transmission.
  • the metallic powders ought not to be fine, but, rather, as coarse as can be produced by a large and rough file.
  • the tube must be sealed; but a vacuum inside it is not essential. A slight vacuum, however, results from having heated it while sealing it. Care must also be taken not to heat the tube too much in the center when sealing it, as it would oxidize the surfaces of the silver stops and also the powder, which would diminish its sensitiveness.
  • I use in sealing the tubes a hydrogen and. air flame. A vacuum is, however, desirable, and I have used one of about one one-thousandth of an' atmosphere, obtained by a mercury-pump. It is also necessary for the powder or grains to be dry and free from grease or dirt, and the files used in producing the same ought to be frequently washed and dried and used when warm.
  • the tube has been well made, it should be sensitive to the induction of an ordinary electric bell when the same is working at one to two yards or more from the tube.
  • tubes may be put in derivation between the tuned plates; but this arrangement is not quite as satisfactory as the single tube. It is necessary when using tubes of the type I have described not to insert in the circuit more than one coil of the Leclanche type, as a higher electromotive force than 1.5 volts is apt to pass a current through the tube even when no oscillations are transmitted. I can, however, construct tubes capable of working with a much higher electromotive force.
  • Fig. 6 shows one of these tubes. In this tube instead of one space or gap filled with filings there are several spaces separated by sections of tight-fitting ,silver wire.
  • a tube thus constructed observing also the rules of construction of my tubes in general, will work satisfactorily if the electromotive force of the battery in circuit with the tube is equal to 1.2 volts multiplied by the number of gaps. With't-his tube, also, it is well not to allow a current of more than one milliampere to pass.
  • the plates 7 are of copper or aluminium or other metal, about half an inch or more broad, about one-fiftieth of an inch thick, and preferably of such alength as to be electrically tuned with the electric oscillations transmitted.
  • the means I adopt for fixing the length of the plates is as follows: I stick a rectangular strip of tin-foil m (see Fig. 7) abouttwenty inches long, (the length depends on the supposed length of wave that one is measuring,) by means of a weak solution of gum, onto a glass plate m. Then by means of a very sharp penknife or pointI cut across the middle of the tin-foil, leaving a mark of division m.
  • this detector If this detector is held in the proximity (four br five yards) and parallel with the axis of the oscillator in action it will showlittle sparks at m. If the length of the pieces of tin-foil approximates to the length of wave emitted from the oscillator, the spark will take place between them at a certain distance from the transmitter, which is a maximum when they are of suitable length. 1
  • l is acylindrical parabolic reflector similar to that used at the transmitting-station.
  • the reflectors applied to the receiver and transmitterought to be, preferably, in length cylindrical reflectors; but it is also possibleto use ordinary concave reflectors, preferably .parabolic, such as are used for projectors.
  • the tube 3' When no oscillations are sent from the transmitting-station, the tube 3' does not conduct the current and the local-battery circuit is broken; but when the powder .or tube is influenced by the electrical oscillations from the transmitter it conducts and closes the circuit. I find, however, that when once started the powder in the tube continues to conduct even when the oscillations from the trans mitter have ceased; but if itbe shaken or tapped the circuit is broken. A tube well prepared will instantly interrupt the current passing through it at the slightest tap, provided it is inserted in a circuit in which there is little self-induction and small electronic? tive force, such as a single cell, and where the effects of self-induction have been removed by one of the methods which I will presently describe.
  • the two plates communicate with the local circuit through two very small coils k, which I will call choking-coils, formed by windingafewinches of very thin andinsulated copper wire around a bit of iron wire about an inch and a half long.
  • the object of these choking-coils is to prevent the high-frequency oscillation induced-across these plates by the transmitter from dissipatingitself by running along the local-battery wires, which might weaken. its effect on the sensitive tube j.
  • These choking-coils may, however, be sometimes replaced by'simple thin wires. They may also be connected directly to the tube j.
  • the local circuit in which the sensitive tube jis inserted contains a sensigive relay n, pref- ,erably wound'to a resistanc of about twelve hundred ohms.
  • This resistance need not be necessarily that of the relay, but may be the sum of the resistance of the relay and another additional resistance.
  • the relay ought to be one possessing small self-induction.
  • the plates is, tube j, and coils 1: are fastoned by means of wire stitches 0' to a thin glass tube 0, preferably not longer than IIO twelve inches, firmly fixed at one end to a strong piece of timber 0 This may be done by means of wood or ebonite grasping-screws.
  • trembler p can also, however, be worked in series with the trembler.
  • a special adjustment of the same is sometimes needed to enable one to obtain dots and dashes.
  • the circuit actuated by the relay contains an ordinary battery '1' of about twelve cells and the trembler p, the resistance of the winding of which should be about one thousand ohms, and the core ought preferably to be of soft iron, hollow and split lengthwise, like most electromagnets used in telegraph instruments;
  • the telegraphic or other apparatus h which one may desire to work. It is desirable that this instrument or-apparatus if on a derivation should have a resistance equal to the resistance of the trembler p.
  • a platinoid resistance h of about five times the resistance of the instrument is inserted in derivation across the terminals of the instrument and connected as close to the same as possible.
  • the number of these tubes in series across the said terminals ought to be about ten for a'circuit of fifteen volts, so as to prevent, in consequence of their counter electromotive force, the current of the local battery from passing through them, but allowing the 'high-tension jerk of current generated at the opening of the circuit in the relay to pass smoothly across them without producing perturbing sparks at the movable contact of the relay. It is also necessary to insert a platinoid resistance in derivation on any apparatus one may be working on the local circuits. These resistances ought also to be inserted in derivation on the terminals of any resistance which maybe apt to give self-induction.
  • t t are two poles connected by a rope t, to which are suspended, by means of insulatingsuspenders, two metallic plates 25 t, preferably in the form of cylinders closed at the top, connected to the spheres e (in oil or other dielectric, as before) and to the other balls t in proximity to the spheres c, in communication with the coil or transformer c.
  • the balls t are not absolutely necessary, as the plates t may be made to communicate with the coil or transformer by means of thin insulated wires.
  • the receiver I adopt with this transmitter is similar to it, except that the spheres e are replaced by the sensitive tube 9' and plates 70, while the spheres t are replaced by the choking-coils k, in communication with the local circuit. It may be ob served that, other conditions being equal, the larger the plates at the transmitter and receiver and the higher they are from the earth and to a certain extent-the farther apart they are the greater is the distance at which corj respondence is possible.
  • I When transmitting with connections to the earth or water, I use a transmitter as shown in Fig. 10. I connect one of the spheres d to earthE, preferably by thick wire, and the other to a plate or elevated conductor u, carried by a pole 'vand insulated from earth, or the spheres d may be omitted and one of the spheres e be connected to earth and the other to the plate or conductor it. At the receiv-' ing-station, Fig. 11, I connect one terminal .of the sensitive tube 3' to earth E, also by a thick wire, and the other to a plate or elevated conductor it, preferably similar to u. The plate in maybe suspended on a pole a: and must be insulated from earth.
  • the apparatus above described is so sensitive that it is essential either that the transmitters and receivers at each station should be at a considerable distance from each other or that they should be screened from each other by stout metal plates. It is sufficient to have all the telegraphic apparatus in a metal box and any exposed part of the circuit of the receiver inclosed in metallic tubes which are in electrical communication with the box. Of course the part of the apparatus which has to receive the radiation from the distant station must not be inclosed, but possibly screened from the local transmitter by means of metallic sheets. When working through the earth or water, the local receiver must be switched out of circuit when the transmitter is at work, and this may also be done when working through air.
  • the operation of my apparatus and system of communication or signals is as follows:
  • the Ruhmkorfi coil orother source of high tension electrically capable of producing Hertz oscillations being in circuit with a signaling instrument-such as a Morsekey, for instancethe operator by closing the circuit in the .way commonly employed for producing dots and dashes in ordinary telegraphy will cause the oscillator to produce either a short or a more prolonged electric discharge or spark or succession of sparks, and this will cause 7 a corresponding short or more pro longed oscillation in the surrounding medium corresponding in duration to the short or longer electrical impulse which in ordinary telegraphy produces a. dot or dash.
  • Such oscillations of defined character will thereupon be propagated as such throughout the medium and will aflect a propgriy -constructed instrument at a distant receiving-station.
  • the imperfect-contact instrument is in circuit with a relay, and when oscillations from the transmitting-station reach and act upon such imperfect contact its resistance is reduced, and the circuit is thereby closed during thecontinuance of the oscillation and for a lengthof time corresponding thereto.
  • the closing of the relay-circuit causes the station are both arranged with one terminal sounder or other signal apparatus to act in accordancewith the particular oscillation received, and the oscillation also immediately starts the action of the shaking or tapping device, which so shakes the powder in'the imperfect-contact instrument as to cause it to break circuit as soon as the oscillation ceases which has closed the circuit and produced a movement of'the signaling instrument corresponding thereto. I am therefore enabled to communicate signals telegraphiccontaining the same.
  • What I claim is- 1.
  • the combination in the receiver, of an imperfect electrical contact, a circuit through the contact, and a receiving instrument operated by the influence of such oscillations on said contact, substantially as and for the purpose described.
  • a receiver for electrical oscillations the combination of a tube containing a metallic powder or powders and mercury, a circnit through the same, and means, controlled by the circuit, for shaking the powder.
  • a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, metallic powder between the plugs, metallic plates connected to the plugs, choking-coils connected to the plugs, a circuit through the coils, plugs and powder, and means, controlled by the circuit, for shaking the powder.
  • a receiver for electrical oscillations the combination of a tube, metallic plugs in the tube, a mixture of metallic powder and mercury between the plugs, choking-coils connected to the plugs, a circuit through the coils, plugs and powder, and means, controlled by the circuit, for shaking the powder.
  • the first claim is as follows:

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