US1246626A - Electric oscillator. - Google Patents

Description

D. G. McCA A.

ELECTRIC OSCILLATOR.

APPLICATION FILED 02130. I915.

1,246,626 Patented N0v. 13, 1917.

@L E? 7L lation to the c:

UNITED STATES Parana ()FFICE.

DAVH G. MOCAA, OF LA'NCSTER, PENNSYLVANIA, ASSIGNOR T0 RADIO 00M- PANY, 0F LANCASTER, PENNSYLVANIA. A CORPORATION OF PENNYLVANIA.

Specification of Letters Patent.

ELECTRIC OSCILLATOR.

Patented Nov. 13, 1917.

This application filed October 30,

1916. Serial No. 128,448.

Lancaster, Lancaster county. State of Penn sylvania, have invented an Electric Oscillator, of which the following is a specification.

My invention relates particularly to apparatus for the production of oscillatory currents of high frequency and the emisslon of electromagnetic waves.

As is known by those skilled in the art, a system of elevated conductors placed either above the earth or above a second system oi eonductors close to but insulated from the earth possesses a definite capacity reth or to said system and is capable of receiving electrical energy and of storing it. similarly to a condenser. If

' some means is provided of such a nature as to permit the stored energy, upon reaching a certain maximum, to discharge into the earth or into a system near the earth, a circuit including the first system will have produced in it high frequency oscillations and a portion of the stored energy will be radiated as earthed clectron'lagnetic waves.

lleretofo're the mcans usnally employed for'discharging'the elevated conductor was a spark gap, which during the discharge be came a part of the oscillator system in which an oscillatory current must nccessarily flow. The spark gap, being of high resistance, caused a serious loss of energy and a material decrease in the number of oscillations consequent-upon each discharge, with a resulting increase in the decrement of the oscillatioi'ls and the production of a wave of poor tuning qualities. Moreover, I have found that in radio telephony, a spark gap in circuit with the microphone seriously interferes with the satisfactory functioning thereof.

One objcct of the present invention therefore is to provide a device .for increasing the encrgystorago function of the elevated conductors in an oscillator system. together with means whereby the oscillations produced in said conductors are transferred to ting electromagnetic waves having good tuning qualities.

These ObjECtS and other, advantageous cnds l secure as hereinaftersct forth, reference being had to the accompanying drawings, in which, l igure 1 is a diagrammatic View illustratmg a system for producing electro-magnetic waves in which the parts are arranged and connected in accordance with my invention; and

Fig. 2 is a diagram illustrating a slightly modified form of the invention.

In the above drawings, 1 represents a source of current, 2 a device for making and breaking the flow of current in the circuit including said source and 3 the primary winding of an induction coil. This latter is provided with a secondary winding 4 connected in a circuit. including a condenser 5 and a quenched spark gap 6. It is ob vious, however, that, without departing from my invention, any other suitable current source and controlling means may be provided for setting up. limiting and cutting ofi' current flow through said spark gap.

()ne terminal of the spark gap is conncclcd to a plain open circuit radiating or main antenna 77,'While its second terminal is connected through a. coil 8 to the earth in such manner that the number of its turns in circuit may be varied at will. This antenna will store energy according to the capacity rclalion between it and the earth and such relation will vary according to the type of said antcnna, being smallest in a straight vertical .orm and largest-wlien the antenna belongs to the invcrtcd or umbrella type. 'It is noted that this capacity relation is ncvcr vcry large and that the amount of encrgy stored before and radiated during discharge is limited.

By long contimicd experiments I have found that the capacity relation and energy storage function of the system or circuit comprised by the parts --68, can be greatly increased by arranging an auxiliary grounded conductor or series of conductors parallel to and interm eshing with the main conductors 7. With this idea in view I mount adjacent the latter a second series of elevated conductors 9 connected to the earth 85 and the waves emitted are sharp and of through a variable inductance and a coil 11 adjustable as to the number of its turns in.- circuit, said coil being, mounted to serve as the secondary of an oscillation transformer whose primary winding consists of the coil 8.

With such an arrangement of parts the circuit 91011 performs at least two dosirable functions, of which the first is to increase the energy storage capacity of the circuit 76"8 during the charging of the la'tter;and the second is to receive the oscillations developed in the circuit 7-6-8 and 9101186'7' and radiate the energy thus received during the discharge of said circuit. Another function is to form an oscillatory circuit consisting of the parts 91011 -8-6-7 which further increases the energy storage ability of the system, there being thus twlo capacities, t. 6., that existing between the antenna 77 and the earth augmented by the earthed conductors 99, and that existing between the antennav wires 7-7 and 9-9 independent of the earth connections. When the oscillations are set up in the circuit 768 by a discharge across the spark ap 6, which occurs upon the closure of the ey 2, the primary winding 8 induces currents in the secondary winding 11, which currents are supplied to the auxiliary conductors 9, causing the circuit in which they are included to act as a radiating antenna in which no spark gap is present. The oscillations produced in this antenna are sustained and of low decrement good tuning qualities.

It is particularly to be noted that owing to the presence of the system or circuit 9-1011, there is no effectual radiation from the circuit 768;-the waves produced by the apparatus being emitted solely by the first named .circuit when the adjustments of the coils 10-811 are such as to cause a maximum transfer of energy from the circuit 7.6-8 to the circuit 9-1011.

If the current readings in-the two circuits be taken, as by hot wire meters, when the above adjustments are made, 'I have foundthat a maximum current in the circuit 910-11 is accompanied by a minimum current in the circuit 7-68, and vice" 10, and varying the number-of turns in the two coils 8 and 11, in which case the number of turns in the coil 8 must be greater cuit 910-11867, and the electrical 7 equivalent of the system shown in Fig. 1, is found in Fig. 2 where said two coils 8 and 11 may be replaced by a single adjustable coil 12 connected between theearth and the point of junction of one end of the coil 16 and one terminal of the spark gap, in which case said single coil likewise serves as an oscillation transformer.

There are therefore two oscillatory systelns supplying the radiating structure 9-1011, for in Fig. 1, the circuit 768 supplies this structure by means of the oscillation transformer 811 and the circuit 9-l011867 supplies the structure 9-1011 by means of the coil 10,

which being common to both circuits operates as an auto transformer. In Fig. 2 the same relations hold for both of the coils 10 and 12 act as auto transformers.

It .,will be seen (Fig. 2 that the circuits 7(512 and 9-106 are ve coupled to the circuit 910'12, f or aside from the electro'magneticcoupling present in the oscillation transformers 10 and 12, there is a capacity coupling between the wires comprising the antennae 7 and 9. This close coupling causes the system to be practicall the quenched gap is used. With an ordinary gap in air, each primary systemscts up oscillations of two different frequencies so that there are four coupling waves and these are-of such a character as to be opposite to each other. Further, with an ordinary gap in air, inwhich the osclllations are not quenched, the branch 7 carries current in one direction and the branch 9 also carries current but in the opposite direction as in a loop antenna, thus causing the pheclos'ely inoperative when any other than nomena found in such an antenna, 2'; 0., the

non-radiation of the fundamental oscillation.

As a result of extensive experiments I have found that a form or type of impulse excitation existswhen a quenched 'ga is. employed in an oscillatory s stem whic is designed in such relation to t 1e current supply. ,system. that a rapid succession of discharges occurs during the flow of each alternating current wave. The quenching of the primary oscillations under these conditions, 11. 0., high group frequencies, is no setting up a (#enched oscillatory current flow in one said conductors; an auto transformer in circuit with the other conductor; and an oscillation transformer inductively connecting said two conductors.

8;"A system consisting of main and auxilia i'y sets of conductors; means for setting up quenched electric oscillations in that part of the system including one of said sets of conductors; a coil connected between said set of conductors and the ground; a second coil in inductive relation with the first coil and connected between the ground and the second set of conductors; with a variable inductance also including in circuit with said second set of conductors.

9. An oscillatory system consisting of a plurality of open oscillatory circuits; a. radiating circuit coupled to said oscillatory circuits; means for transferring energy from said oscillatory circuits to the radiating circuit; and means for preventing said radiating circuit from inducing current in said open circuits.

10. An oscillatory system consisting of a plurality of open oscillatory circuits; a radiating circuit coupled to said oscillatory circuits; means for transferring energy from said oscillatory circuits to the radiating circuit; and means for preventing effectual radiationfrom the open circuits.

11. An oscillatory system consisting of elevated conductors forming a plurality of primary circuits and hav ng parts associated to providea radiating circuit coupled to said primary circuits; means for transferring energy from said primary circuits to the radiating circuit; and means for preventing said radiatin circuit from inducing current in said primary circuits. 12. An oscillatory system consisting of elevated conductors forming a pluralityof primary circuits and having parts associated to constitute a radiating circuit coupled to said primary circuits; means for transferring energy from said primary circuits to the radiating circuit; and means for pre venting effectual radiation from parts of said system other than the radiating circuit. 13. A transmitting system consisting of a plurality of primary circuits having portions associated to. constitute a radiating cir cuit, said primary circuits bein out of resonance with said radiating'circuit and the latter being coupled to the primary circuits under conditions of maximum radiation.

14. A transmitting system consisting of a plurality of primary circuits; a radiating circuit coupled to said primary circuits; with means including a quenched gap for causing in said primary circuits an oscillatory current flow quenched by means other than the reaction of the radiating circuit. DAVID G. MoCAA.

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