US717771A - Signaling system. - Google Patents

Description

No. 717,771. P'ATENTBD JAN. 6,1903; H. SHOE-MAKER. SIGNALING SYSTEM. APPLICATION FILED AUG. 13, 1902.

K0 MODEL.

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HARRY SHOEMAKER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE CONSOLIDATED WIRELESS TELEGRAPH AND TELEPHONE COMPANY AND MARIE V. GEHRING, OF PHILADELPHIA, PENNSYLVANIA.

SIGNALING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 717,771, dated January 6, 1903.

Application filed August 13, 1902- Serial No. 119,468. (No model.)

To aZZ whom it may concern:

Be it known that I, HARRY SHOEMAKER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented anew and useful Signaling System, of which the following is a specification.

My invention relates to electrical signaling systems, more especially those in which the no energy representing the message or signal is transmitted through the natural media in the form of electromagnetic waves or other electroradiant energy.

My invention resides in the employment of :5 a radiating conductor or conductors in connection with which there is no earth connection whatsoever, In long-distance telegraphy heretofore where electromagnetic energy was employed the earth connection was found to be very essential. In my system, however, such earth connections are dispensed with and I am enabled to transmit messages over great distances with great facility.

My invention comprises both transmitter and receiving circuits and apparatus in which the aerial conductor employed is a half or a full wave length of the energy employed in the system in length.

My invention comprises a method of and 0 apparatus for impressing upon the natural media electroradiant energy of a certain frequency and receiving such energy in a receiving-circuit without resorting to the usual ground or earth connections for radiating and receiving conductors.

By my method and apparatus the radiating and receiving conductors are one-half or a full wave length in length and are entirely-insulated from the earth. It is often of the nt- 0 most consequence in wave telegraphy as heretofore practiced that a very good earth connection be obtained. In some instances this is very difficult-as, for example, on a rocky, very sandy, or dry shore, and more especially at stations located in the interior of the country and where the transmission is to take place to a great extent across land. By my method, however, these earth connections are dispensed with, and signaling is easily maintained by the system and appara 5o tus about to be described.

Referring to the accompanying drawings, Figure l is a diagrammatic View of a transmitter-station in which the circuit of the radiating-conductor has a length equal to the length of a wave of electroradiant energy which is transmitted from it. Fig. 2 shows a diagrammatic arrangement of the receiving apparatus in which the receiving-conductor and its circuits is of a length equal to the length of a wave of the radiant energy received upon it. Fig. 3 is adiagrammatic view of the transmitter in cases Where the aerial conductor and its circuit is equal to one-half the length of a wave as radiated from it. Fig. 4 shows a diagrammatic view of the receivercircuit in which the receiving-conductor is one-half the wave length in length.

In Fig. l, B represents a source of energy which when key K is depressed causes cur- 7o rent to flow through the primary 1:: and the interrupter I. This interrupter I is, for example, a mechanically-driven one and serves to interrupt the current-flow through the primaryp at a high rate. This intermittent cur rent in the primary 19 causes induction in the secondary s of high-potential currents, and such secondary 3 serves to charge the condenser C, which is in series with the second primary P. In shunt to the secondary s is a spark-gap G, which, along with the condenser O and the primary P, forms a freely-oscillating circuit, in which there occur oscillations of high frequency upon the discharge of condenser O. The rate of these oscillations depends upon the electrical constants of the circuit C P There are then forced vibrations in the circuit A S A, of which S is, in fact, the secondary of a transformer, and of which A is the usual aerial conductor, and of which A 0 is an idle length of conductor insulated from earth.

Suppose it is desired to transmit electroradiant energy of a frequency such that the wave length is six hundred feet. I then de- 5 sign the circuit A S A so that A is one hundred and fifty feet in height, that the winding S is slightly less than three hundred feet in length, and so that the conductor A is one hundred and fifty feet in length. This lastmentioned conductor A is for convenience rolled into a bundle and insulated from earthas, for example, by being immersed in a vessel of oil or other insulatingmaterial. I have said that the length of the winding S is slightly less than three hundred feet. This I find to be necessary and believe it to be due to the inductance of said winding S. Itis seen from the above figures that the total length of the circuit A S A is six hundred feet, or equal to the full length of the wave transmitted, and is determined by the constants of the circuit C P g.

In Fig. 2 the lengths of A L A are those given in connection with Fig. 1. L in this instance is an inductive winding whose length is approximately three hundred feet, or onehalf the Wave length of the received energy, A is one hundred and fifty feet, and A one hundred and fifty feet. In shunt to the Winding L is a Wave-responsive device WV, which is therefore at all times subjected to a maximum difference of potential existing at the terminals of the winding L. O is a condenser which serves to prevent the short-circuiting of the source of energy B through said winding L. ff are the usual choke-coils, which are connected in series with said wave-responsive device NV and the relay R, between whose windings is source of energy 1). Relay R controls a local circuit in the well-known manner.

In Fig. 3 I have shown the same apparatus as in Fig. 1, except that the tail or lower conductor A is omitted and the secondary S is one hundred and fifty feet in length (nearly) in place of three hundred feet, as in Fig. 1. In this instance, A is one hundred and fifty feet, and therefore the entire circuit A S combined is three hundred feet, or one-half the length of the wave as trans mitted.

In Fig. 4 the receiving device corresponds with that shown in Fig. 2, except that the winding L is one hundred and fifty feet in place of three hundred feet in length and the lower extension-conductor A is omitted. By this arrangement I have communicated signals between stations separated at least forty miles from each other and find that no earth connection whatsoever is required if the above proportions are observed. I found also in my experiment that atmospheric disturbances such as those resulting from trolley-sparks and the like do not interfere with my system to give false signals. The'probable explanation for this resides in the fact that the electromagnetic wave emitted by the inductive spark such as obtained from the trolley-circuitsand the like is extremely short, and inasmuch as there is no ground connection and the aerial conductor is of such dimensions as to respond only to much longer waves practically no difierence of potential is exerted at the terminals of the Wave-responsive device,whereasin the case of grounded systems short electromagnetic Waves, as well as long ones, will be conducted to the earth connections of the wave-responsive device and cause a false signal.

What I claim now, and desire to secure by Letters Patent, is-

1. In asignaling system, aconductor whose length is equal to that of the wave radiated therefrom and received thereupon.

2. In a wireless signaling system, a radiating or receiving conductor, a winding in series therewith and having a length approximately equal to half the length of the wave radiated therefrom or received thereupon.

3. In a wireless signaling system, a radiating or receiving conductor, comprising a winding having a length approximately equal to half the length of the transmitted or received Waves, and a portion whose length is approximately one-quarter the length of the transmitted or received waves.

4. In a wireless signaling system, an ungrounded conductor, comprising in part a winding of a length approximately equal to one-half the length of the received or transmitted waves.

5. In a wireless signaling system, an ungrounded conductor, comprising a winding of a length approximately equal to one-half the length of the transmitted or received waves, and a portion of a length approximately equal to one-quarter the length of the transmitted or received Waves.

6. In a wireless signaling system, a conductor comprising a winding of a length approximately equal to one-half the length of the received or transmitted Waves, and having in addition a length approximately equal to or a multiple of a quarter wave length.

7. In a wireless signaling system, an oscillating circuit, a transformer-primary in said circuit, a radiating circuit comprising the secondary winding of said transformer, the length of said winding being approximately equal to one-half the length of the transmitted Waves, and a conductor in said circuit of a length approximately equal to or a multiple of one-quarter wave length.

8. In a wireless signaling system, a transmitting or receiving conductor comprising portions of lengths equal to one-quarter the length of the transmitted or received waves, and a winding intermediate said portions and of a length approximately equal to one-half the length of the transmitted or received waves.

HARRY SHOEMAKER.

Witnesses:

G. S. EvEs, ALICE T. BURRAIGH.

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