US2146247A - Antenna system - Google Patents

Description

Feb. 7, 1939. BELLINI 2,146,247

ANTENNA SYSTEM Filed Feb. 11, 1936 INVENTOR 77055 5 LL/A l ATTORNEY Patented Feb. 7, 1939 UNITED STATES ANTENNA $YSTEM Ettore Bellini, Paris, France, assignor to Compagnie Generale de corporation of France Telegraphic Sans Fil, a

Application February 11, 1936, Serial No. 63,309

In France February 15, 1935 8 Claims.

This invention relates to antenna systems and has for its object to provide improvements over the so-called Adcock antenna.

As' is known, an ordinary frame used for radio goniometers produces errors in altitude which may reach 90 if the electrical field is a horizontal one or includes a horizontal component. This case presents itself during the night.

In order to avoid these errors it is necessary that the antenna system shall not be influenced by the horizontal electrical field. As is known, the Adcock system at least partially fulfills this condition.

The principal feature forming the subject matter of the present invention consists of counteracting the electromotive force excited in a horizontal or oblique conductor caused by the horizontal electrical field, this being accomplished by an electromotive force of equal value and opposite sign, induced by the current passing through a tuned vertical frame subjected to the action of the same field.

Figures 1, 2 and 3 show diagrammatically three different embodiments of my invention.

In Fig. 1, an aerial of U-shape is considered. The horizontal electrical field excites in the horizontal branch AB, an electromotive force which is counteracted by an equal electromotive force of opposite sign, induced by the current circulating in the vertical frame a b c d, tuned by the condenser C to the frequency to be received by means of mutual inductances suitably oriented. The current in the frame is being excited by the same electromagnetic field which produces the electromotive force in AB. The resistor R serves for adapting the intensity of the current so as to obtain compensation.

This compensation is possible of accomplishment and always valuable since, as the experiences of Smith-Rose and Barfield (Proceedings of the Royal Society, A, volume 110, 1926) have demonstrated, the horizontal electrical field always propagates on the surface of the ground, close to a few degrees along the vertical direction.

The calculations readily show that the mutual inductions must have the value I 50 41rnh wherein 1 represents the length AB, h the effective height of the frame, 11 is the frequency, and R is the resistance of the frame.

As shown in Fig. 2, the coupling coil S of the radio-goniometer, and the horizontal branch of the aerial of U-shape are enclosed by a shield forming part of the compensating frame. Although the phase of the current in the frame is retarded by ((1 being the height of the frame) with respect to the phase suited for exact compensation, this deficiency is sufiiciently small to be neglected.

The mutual induction in this case is that existing between the branch AB and the shield. It is known in fact that the current passing in a tubular conductor produces an electromotive force in a conductor situated therein (see: PomeyA paradoxial effect of electromagnetic induction-Revue Generale dElectricity, May 5, 1934).

It will be understood that the input circuit for any suitable goniometric apparatus M may be coupled to the coil S.

In the frame of Fig. 3, the horizontal electrical field excites electromotive forces in the sides at and Cd. These electromotive forces are suppressed by the action of the currents circulating in the two tuned frames.

It will thus be seen that I have provided a system for compensating electromotive forces in conductors, in particular for suppressing the night effect in radiogoniometers. My method consists in coupling these conductors to frames in a suitable manner and subjecting them to the action of the same field which produces the electromotive force to be neutralized.

I claim:

1. A receiving antenna system comprising two upright energy-collecting arms, a horizontally disposed conductor interconnecting the lowermost portions of said arms, conductive means insulated from ground and paralleling said horizontally disposed conductor for providing an electromotive force in opposition to the spaceenergy collected by said horizontally disposed conductor, said conductive means and said horizontally disposed conductor being electrically insulated from and inductively related to one another, means for tuning said conductive means to the frequency of said space energy, goniometric apparatus operable in response to signals collected by the upright energy collecting arms, and a transformer having a primary in circuit between the two halves of said horizontally disposed conductor and a secondary through which signals are fed from said upright energy-collecting arms to said goniometric apparatus.

2. A system in accordance with claim 1 and having said conductive means constituted as a metallic tube surrounding the horizontally disposed conductor.

3. A system in accordance with claim 1 and having in addition to said horizontally disposed conductor a similar conductor interconnecting the uppermost portions of said arms, andtunable conductive means insulated from ground and paralleling the last said conductor for the same purposes set forth in respect to the first said paralleling conductive means.

4. In an antenna system, a pair of verticallydisposed space energy collectors, at least one horizontally disposed conductor interconnecting said energy collectors, ungrounded tunable means paralleling said horizontally disposed conductor and insulated therefrom for collecting space energy having a polarization component which is different from that which the vertically disposed collectors are intended to collect, means including a variable impedance for so adjusting the value of the energy collected by the last said means in relation to the energy collected by said horizontally disposed conductor that said ener gies reactively oppose and neutralize one another, and a utilization circuit coupled to said horizontally disposed conductor at the center of symmetry thereof.

5. In combination, a directive aerial comprising vertical and non-vertical conductors, and a device for suppressing the electromotive force generatedby an electromagnetic field in the said non-vertical conductors, said device comprising an ungrounded tuned loop and means for magnetically and symmetrically coupling said loop with at least one of the said non-vertical conductors.

6. The combination claimed in the claim 5,

wherein one side of the tuned loop is constituted by a tube surrounding a non-vertical conductor of the aerial.

'7. In combination, a loop aerial having two horizontal sides and two vertical sides, and a device for suppressing the electromotive force gen erated by an electromagnetic field in the said horizontal sides, said device comprising two separate tuned ungrounded loops and means for magnetically and symmetrically coupling said loops respectively with each of said horizontalvsides.

8. The device according to claim 5 in combination with at least one variable resistance in the circuit of the tuned loop.

E'I'IORE BELLINI.

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