US884989A - Wireless telegraphy. - Google Patents

Description

' PATENTED APR. 14, 1908. G. MARCONL WIRELESS TELEGRAPHY APPLICATION FILED FEB. 9, 1 04,

ilNiE an GUGLIELMO MARCONI, or LONDON,

'1. EN FFIQEQ ENGLAND, ASSIGNOR TO MARCONI WIRELESS TELE- WIRELESS 'I'IELEGRAPHY.

Original application filed November 28, 1902,

' Specification of Letters Patent.

Patented April 14, 1908.

Serial No. 182,97. Divided and. application filed February 2, 1903,

Serial No. 141,399. Again divided and this application filed February 9, 1904. Serial N 0. 192,739.

To all whom "it may concern:

Be it known that I, GUeLrELMo MARooNI,

a subject of the Kin of Italy, and a resident of London, En lan have invented certain new and .usefu Improvements in Wireless Telegraphy, of which the following is a full and true description, reference being had to. the accompanying drawings, showing one form of apparatus adapted to carry out my invention.

The present application is a division of an application, Serial No. 141,399, filed by me on February 2, 1903, for Letters Patent of the United States, which application was a division of my application Serial N 0. 132,974, filed by me on November 28, 1902, for Let-- ters Patent of the United States.

My present invention relates to the system of wireless telegraphy in which ller'tzian waves' or oscillations of high frequency are produced at a transmitting station by means of an abrupt electrical discharge in the natural n'ledium, whence the oscillations are propagated. to a distant receiving station without the use of any conductor or connecting wires. l

My present theory of the method hereinafter described is as follows, although I intend to claim this method, whether this theory is corrcctor not :-.It is a well known fact that after any change has taken place in the magnetic force acting on a piece of iron, some. time clapses before the corre sponding change in the magnetic state of the iron is completed. If the. applied magnetic force be either subjected to a gradual increase followed by an equally gradual diminution or caused to effect a cyclic varie tion, the corresponding induced magnetic variation in the iron will lag behind the changes in the applied force. To this tendency to lag behind, Prof, Ewing has given the name magnetic hysteresis. It has also been shown by Gcrosa, Fin'zi, and others that the effect of altcrna ting currents or high frequency electrical oscillations actin upon iron is to reduce considerably theae ects ofsmagnetic hysteresis, causing the vmetal to 'I'es 0nd much more readily toany influence which tends to alter its magnetic condition. The eiiect'of electrical oscillations prpbably is to bring about a momentary release of the molecules of iron from the constraint (or vlscosity) in which they are ordinarily held,

quently decreasin the lag in the magnetic variation taking p ace in the iron. I, there- 'fore,,anticipated that the group of electric waves emitted by each spark of a Hertzian radiator would, if caused to act upon apiece of iron which is being subjected at the same time to the slowly varying magnetic force, produce sudden variations in its magnetic hysteresis, which variations would produce others of a sudden or jerky nature in its magnetic condition. In other words, the magnetization of the iron, instead of slowly to lowing the variations of the magnetic force applied, would at each spark of the transmitter suddenly diminish its magnetic lag caused by hysteresis. These jerks in the magnetic condition of the iron would cause induced currents in a coil of wire of strength suflicient to allow the si nals transmitted to be de: tectedintelligil.) y on a telephone, or perhaps even read on a galvanon'ieter. The jerks in the magnetic condition of the ironmight also be detected by a telephone diaphragm-11p plied directly thereto.

In carrying out my present improvements,

I avail myself of the discovery made by me that if at a receiving station a magnetic field be created independent of received oscillations, and a receiving instrument be connected with said field, the received oscillations may be utilized to varythe current of the circuit of the receiving instruments so as to render the received oscillations intelligible as signals. I

The drawings show a form of apparatus adapted to carry out the method of my pres cnt invention, which apparatus was shown and described in'my application Serial No. 132,974, and also in my application Serial No. 141,399. i

a In the drawings, Figure 1 is a front elevation (partly diagrammatic) of a preferred form of myrecciving device, and Fig. 2 is a similar side elevation of said device.

which may be bent upwards; it may consist of say thirty hard drawn iron wires of about 5 mm. in diameter. Over this, a primary winding .of one or more layers of thin silk winding is connected to a capacity E, which may be the earth, and the other end of the winding connected directly, or indirectly, to

diminishing theirretentiveness and conse- 55 Int-his apparatus a is a core, the, ends of covered wire I) is placed, and one end of the 20 I shown, itcauses a constant-change of suca receiving conductor A. The receiving l conductor is shown as an elevated vertical conductor, but obviously this conductor may be otherwise disposed, as horizontally, or any of the different forms of receiving conductors developed in the progress of wireless telegraphy may be used. A seecessive reversals or alterations in the magnetismof the core, trical oscillations of suitable period are sent from a transmitting station,'accord1ng to the now well known methods, changes are effected in the magnetism of the iron core in addition to the chan es in magnetism of the core produced by t e rotation of the magnet, and these ohangesproduce induced changes on the windings, and these currents in their turn reproduce on thetelephone or other instrument ada ted to render the received oscillations inte ligible, the signal sent from the transmittin station.

The telep one or other proper instrument may be connected to the ends of the winding b nearest the iron, and the winding 0 omitted; or the iron core a may be )laced in close proximit to a telephone diap ragm,- and the sudden c anges of magnetism 1n the core can then be detected by sounds produced by the diaphragm. In this case also, no second Windin is required on the core. a

It Wi 1 be seen that in my apparatus a magnetic field is created by the magnet cl. In this field the, coil 1), connected to the aerial conductor, is located, and the received OSClllations passing through this coil serve to modify the field of the magnet d. The modifications of this field set up currents in the coil 0, and these currents cause sound waves to be set up in the telephone. In order to localize the field in proximity to the coils and c, thecore a is inserted, this corebeing of magnetic material, and having a magnetic permeability greater than that of air.

The arrangement described forms a magnetic circuit composed ofi the movable body (1, the stationary body a, and the gaps between the ends of these two bodies. Owing to the fact that the elements comprising this circuit are of different magnetic permeability, a movement of one of these elements rea It is found that if eleci vely to the others causes a variation of other forms of apparatus than those de-- scribed and shown, and 1 do not, therciore wish to be understood as limiting my invention thereto.

I have shown and described an apparatus in which-the magnet, which creates the field independently of the received oscillations, is

movable, and the core is stationary, but I do not intend to limit my claims to this specilic form of the invention as many forms of said invention will be obvious to the skilled mechanic.

The scope of my invention is indicated by the l'ollowing claims:

1. In a wireless telegraph system, the method of detecting electrical oscillations ol high frequency,which consists in creating a rotating magnetic field at a receiving station, abru itly varying said field by the received oscillations, and utilizing the variations in said. lield to create intelligible signals.

2. In a wireless telegraph system, the method 0t detecting electrical oscillations of high frequency, which consists in creating a rotating magnetic licld at a receiving station,

' partially localizii'ig said field at a. point within the same, varying the magnetism of the localized portion 01'' the lield by the received oscillations, and utilizing such variations to create intelligible: signals.

3. In a wireless telegraph system, the method of detecting electrical oscillations of high frequency, which consists in creating a magnetic held at a receiving station, localizing said held by a stationary member-having a magnetic permeability greater than that of air, varying the llllX through said stationary member by the movement of a mag nctic body, modilying said flux by the rcceived oscillations and utilizing such modifications to create intelligible signals, substantially as described.

4. in a wireless telegraph system, the method of detecting electrical oscillations of high frequency, which consists in creating a magnetic licld at a rccciving station, localizing said licld by a stationary member having a magnetic permeability greater than that ol air, varying the flux through said stationary member by the movement, of a magnetic body in proximity thereto, abruptly modifying said flux by the received oscillations and utilizing said abrupt modifications to actuate a telephone, substantially as described.

5. lna wireless telegraph system, the method of detecting electrical oscillations of high frequency, which consists in creating a current 1pulsations in a telephone circuit, sub-. 10

magnetic field at a receiving station, localizing said. field'by a stationary member having stantial y as described.

In witness whereof, I have hereunto set my a magnetic permeability greater than that of hand this 25th day of January 1904. 1

air, varying the flux through said stationary member by the movement of a magnetic body in proximity thereto, abru tly modifying said flux by the received 0sc1 lations', and utilizing such abrupt modifications to induce GUGLIELMO MAROONI.

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