US1151098A - Radiotelegraphic plant. - Google Patents

Description

E.- GIRARDEAU.

RADIOIELEGRAPHIC PLANT.

APPLICATION FILED DEC. 1, 19H.

Patented Aug. 24, 1915.

UNITED STATES PATENT OFFICE.

EMILE GIIBARDEAU, OF PARIS, FRANCE, ASSIGNOR OF ONE-HALF TO JOSEPH IBETHENOD,

' OF PARIS, FRANCE.

- RADIOTELEGRAPHIC PLANT.

To allwlm'm it may concern Be it known that I, EMILE GIRARDEAU, engineer, a citizen of the Republic of France, residing at Paris, in the Republic of France, have invented certain new and useful Improvements in Radiotelegraphic Plants, for which application has been'made in France December 1, 1910.

A receiver for radiotelegraphic plants ought to possess theoretically the following properties, viz

1. It ought to be adapted to be-tuned for waves of various lengths while preserving always the, same sensitiveness whichever may be the length of the wave.

2. It ought to permit the maximum of syntony after the tuning with the corresponding station has been once effected to be obtained.

3. It ought to comprise as few regulating devices as possible.

4. It ought to require as little space as possible.

Practically the simultaneous realization of all these conditions presents great ditficulties owing to the fact that, in order to attain a sufficient syntony, an induction jigger with separate windings has to be used,

although this jigger oflers certainly from a good many points of view much greater complications than the jigger with simple winding used for shunting. However it is evident, that the construction of a single j1gger is much simpler than the construc- .tion of two, one of which then must be provided with a device permitting the changing of their relative positions.

This invention relates to a new receiver which particularly offers in the most complete form all the properties hereinbefore enumerated. This improved apparatus is based upon the following principles: In a normal receiver post with induction jigger, this jiggcr, considered by itself, constitutes a converter without iron having a determined dispersion coeiiicient c. On the other hand if X designates the ratio of the coefficient of the apparent self-induction of the antenna with regard to the coefiicient of self-induction of the primary winding of the jigger, it is clear that the coefficient of the real coupling between the two circuits,

Specification of Letters Patent.

Patented Aug. 24, 1915.

Application filed. December 1, 1911. Serial No. 663,360.

the primary and the secondary of the recelver system, is equal tot =x/ as 9 1+1 This equation is the result ofthe follow- 1ng development: If the respective coeflicients of self-induction of one of the n prithat the total primary self-induction is l -l-nl and the total secondary induction is M The total mutual induction is measured by n m and the following equation may be written out in accord with the well known definitions used in the theoretical study of high frequency currents:

In order to adapt the apparatus to the various lengths of waves between 0 and a maximum, the coupling coefiicient must be varied between zero and the maximum;

and finally it therefore is necessary to act upon according to the formula hereinbefore stated; this is however not very rational. According to this invention this inconvenience 1s avoided by subsituting for the single jigger,

generally used, a certain number of pggers, the primary and secondary windings of which are respectively connected in series; according to the wave length of the sender station the number of such jiggers is varied by means of a suitable connnutator and in applying the formula as above one can easily verify whether the coupling coeiticient remains constant whichever may be the number of jiggers coupled for a given number of x.

In the accompanying drawings a diagram of connections and a coupling apparatus for the jigger is shown by way of example.

Figure 1 shows the apparatus with four jiggers. Fig. 2 illustrates a modified construction permitting of the easy and simultaneous regulation of all the jiggers in very wide limits.

In Fig. 1, the antenna A is connected with the primaries P P P P of the jiggers in question through the intermediary of the self-inductance S, the ground contact T being insured by a conductor'in which the condenser C is inserted. The secondaries S S 8,, S, are mounted as well as the primaries in series in the circuit of the detector D.

By means of the commutators M, M it.

is evidently possible to vary the number of jiggers actually in use, according to the length of wave from the sender station, said commutators M, M being adapted to be connected with each other in such a manner that the one participates in the movements of the other. Thus, as shown in Fig. 1, the commutators M, M canbe mounted upon an insulated regulator handle 0 allowing their simultaneous operation, so that the commutator M rests uponthe contact 1 when the commutator M rests upon contact 1' and the commutator M rests upon contact 2 when the commutator M rests upon contact 2', etc. It is obvious that there can be provided any number n) of jiggers. As regards the coupling coetlicient p it can be modified at will it' one acts upon 6, that is to say by changing the relative position of the primaries and of the secondaries.

According to Fig. 2 the (n) primary windings are wound around bobbins P which are shown in section; these (n) bobbins are arranged -in a circle around the axis X, X and they are fixed in a frame B. The (n) secondary bobbins S are mounted upon a frame B". The coupling ot' the bobbins can be varied within very wide limits if one of the frames is made to turn around the axis X, X so that the coetlicient p can exactly attain the value zero. This angular displacement can be replaced by or combined with a movement of translation of one of the frames along the axis X, X; in this case the diameters of the primary and secondary bobbins will be chosen of different width so as to permit of the bobbins being telescoped one into the other at the end of the movement of translation. The platform B which supports the primaries P is provided with a socket I, which forms a threaded guide for the screw V which can be turned by means of a rifled knob (lr. A key ll extending through a fork J carried by the socket I prevents the rotation of the platform l3, and consequently compels the same to execute a vertical movement upon the rotation of the screw V. However. as soon as the platform I) arrives at the end of its path it will abut against the shoulder l, and ll is at this moment disengaged from the fork J and the platform 13 turns in a. horizontal plane.

The form of execution of the principle of invention hereinbet'ore described evidently possesses the PI'OIXltlQS mentioned under numbers 1, 3 and 4.

There is further obtained a very pronounced syntony owing to the great facility with which the coupling can be modified. In the cases where the synton'y ought to be pushed to the extreme there can easily be established an intermediary circuit by the adjunction ot' a simple interrupter. It the interrupter is placed at I (Fig. 1) a loop will be formed it' the said interrupter is closed, said loop being composed of the selfinductance S, of the primaries P. P,,, I,

and of condenser C. This loop constitutes an intermediary circuit oscillating between the system of the ground antenna and the series of jiggers. the coupling with the said system being besides easy to regulate by displacing for example the contact It.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is:

1. Receiver for radio-telegraphic stations comprising an antenna, a plurality of induction-jiggers having their primaries, consisting of coils separated to such a distance that they have no influence upon each other, arranged in series with each other and their secondaries in series with each other, and means for switching into circuit a greater or smaller number of induction jiggers according to the waves received from the sender station. 1

Receiver for radio-telegraphic stations comprising a plurality of induction-jiggers, a displaceable frame upon which the primaries of said induction-jiggers are mounted, means for displacing said frame for varying the relative position of the primaries with respect to the secondaries, and means for mechanically coupling the primary and secondary of the transformer so that the number of coils in each can be varied uniformly and simultaneously.

3. In a receiver for radio-telegraphic stations comprising an antenna, a plurality of jiggers having their primaries and their secondaries arranged in series, a self-inductance apart of which connects the primaries of said jiggers with said antenna, a condenser between said jiggers and the ground, and means for grounding a point of the selfinductance for establishing an intermediary circuit comprising self-inductance of the primary jigger windings and said condenser, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

EMILE GIRARDEAU.

Witnesses:

J. BETHENQD, BARTLEY F. Yos'r.

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