US1496155A - Art of radiocommunication - Google Patents

Description

June 3, 1924. 1,496,155

F. J. FRANssoN ART OF RADTO COMMUNICATION Filed Nov. 8, 1919 wrmz'ss I ?atented June 3, I924.

1 SITE PATENT OFFICE.

FRANS J. FRANSSON, OF SHORT HILLS, NEW JERSEY, ASSIGNOR T0 AMERICAN GAS ACCUMULATO'R COMPANY, OF ELIZABETH, NEW JERSEY, A. CORPORATION OF NEW Jnnsny.

ART or RADIOC'OMMTIINICATION.

Application filedNovember 8, 1919. Serial No. 336,658.

To all whom it may concern:

Be itknownthat I, Fn-ANs J. FRANssoN, a subject of the King of Sweden, and a resident of Short Hills, in the county of Essex and- State of New Jersey, have invented an Improvement in the Art of Radiocommunication. of which the following is a specification.

This invention relates to the art of radio communication and more particularly to a duplex system of wireless telegraphy or telephony in which waves or messages may and received messages and, for balancingpurposes, an absorbing circuit or dummy antenna is in some instances coupled to the main antenna, such absorbing circuit being, however, very undesirable because it consumes considerable energy. In other known duplex wireless systems, complicated and inefiicient means are employed to avoid mutual interference in receiving and transmitting, both transmitting and receiving means in some of such systems being coupled to the loop antenna which latter is grounded.

The improved system embodying the present invention overcomes the undesirable features of the systems heretofore known and, in its broader aspects, comprises a system of aero wires or an antenna means arranged so as to include both a loop antenna and an open or plain antenna, whereby the desirable features of both types of antenna may bentilized. Both the loop antenna and the open antenna may have suitable variable inductance or capacitance or both in circuit therewith, for varying the reactance of the antenna and so arranged and balanced that the oscillations set up in the antenna means Will not interfere. Hence the messages or waves transmitted by the transmitting -me'ans coupled to the antenna means or to one branch thereof, will not interfere with" the messages or waves simultaneously re"- ceived by the receiving means that iscoupled' to the antenna means or toits other branch, and vice versa. In this antenna system waves of the same or different wave length may be received and transmitted simultaneously without mutually interfering with one another.

The above and otherobjects and the novel features of the inventions herein disclosed will be apparent from the following descrip tion taken in connection with the figures of the accompanyingdrawing which forms a part of this application. It is to be underillustrate some of, the more desirable embodiments of the broad underlying princi ples of this invention. but the invention is not confined to those systems herein disclosed.

Moreover, the inventions herein disclosed are equally applicable to duplex systems of wireless telegraphy and wireless telephony, the proper or well known transmitting and receiving apparatus in either case being used.

In the drawing-'- Figure 1 is a diagram of a duplex radio system of communication that embodies the present invention; and

Figures 2 to 6 inclusive are similar diagrams of modified-systems, each embodying this invention;

Referring to Figures 1 and 2, the antenna or system of aero wires for transmitting and receiving the waves to and from other'stations comprises a combination of a loop or closed antenna A and an open or grounded antenna- B. The antenna or oscillator means A and B may be of any suitable construction to cooperate in the manner and for the purpose desired. The most desirable arrangement is one in which the loop or closed antenna circuit A includes adjustable means such as variable inductance or variablecapacity or both and an open or grounded antenna portion 13* is provided with the usual coupling inductance coil and variable condenser" for tuning or varying the wave length, such antenna portion B" being connected to the loop antenna circuit A in sucha relation that after the proper adjustment of the variable element or elements, a balanced condition will be obtained in which there will stood that the figures of this drawing merely be no flow of current from the loo-p antenna to the open antenna when the transmitting means is coupled to the loop antenna, and in which the flow of current from the open antenna to the loop antenna will be neutralized in the loop antenna, when the transmitting means is coupled to the open antenna. The particularly desirable loop antenna means A herein shown comprises the wires 10 and 12 connected to the ends of the wire 11, and respectively connected to terminals of the variable condensers 13 and 14. The other terminals of the condense s 13 and 14. may be connected together by suitable inductance means, thereby completing the loop antenna circuit A. A particularly desirable form of connecting link between the condensers 13 and 1 consists of two in dependently variable inductances or coupling coils 15 and 16 respectively connected to the condensers 13 and 14, and to each other at 17.

The open or grounded antenna means B may be of any suitable type that will cooperate with the loop antenna means A and the receiving and the transmitting means in the manner and for the purpose desired. The antenna B herein shown is a particularly desirable construction and con sists of a variable inductance or coupling coil 18 that is connected by a conductor 19 to the common connection point 17 of the inductance coils 15 and 16 of the loop antenna A. The inductance 18 is also connected to the variable condenser 20 by a conductor 21, the said condenser being grounded, as at G.

By properly adjusting the various elements of the system to resonance, either a receiver R or a transmitter T may be used in or associated with the loop portion A of the antenna in combination with a transmitter T or a receiver R in or associated with the open or ground portion B of the antenna, as indicated respectively in Figures 1 and 2. In the several views of the drawing the receiving means R and the transmitting means T are, respectively,

only diagrammatically shown because any suitable or preferred transmitting means adapted for wireless telegraphy or wireless telephony may be employed that will properly supply the energy and produce the telegraphic or telephonic waves desired to be transmitted. Likewise, any suitable or preferred telegraphic or telephonic receiving means may be employed that may be tuned to the incoming waves to properly receive them telegraph or telephone messages.

In Fig. 1, for example, the inductance coil of the receiver R is shown as inductively coupled to or associated with the inductance coils 15 and 16 of the loop antenna circuit A and the inductance coil of the neutralized and the transmitting apparatus transmitter T is shown as inductively coupled to or associated with the inductance coil 18 of the grounded antenna circuit B. With the several variable elements adjusted for resonance, the receiver R and transmitter T may operate simultaneously to receive waves from other stations and transmit waves to other stations without mutual interference. The currents induced by the transmitter T in the inductance 18 will flow in equal and opposite directions, through the inductances 15 and 16, and, accordingly, currents induced thereby in the inductance coil of the receiver R will be 80 will therefore have no efiect upon the in dicating means of the receiving apparatus.

The loop antenna circuit A is utilized for receiving purposes, the waves generated at the distant station causing a current to flow or oscillate in the loop antenna and at a given instant such current will flow in the same direction through the inductances 15 and 16, inducing currents in the receiver inductance coil R to cause operation of the receiving apparatus.

In the arrangement shown in Figure 2, the inductance coil of the transmitter T is inductively connected to or associated with the inductance coils 15 and 16, and when the various elements are properly adjusted and balanced, none of the transmitted current or energy will flow to ground through the. inductance 18. and the receiving apparatus R coupled to the coil 18 will therefore not be affected in any way by the transmitter. However, signals from other stations will be received on the antenna system A, B, operating as an open antenna, whereby the receiving apparatus will be operated by outside waves but not by those generated by the associated transmitter. In this arrangement, the antenna inductance 18, the receiver inductance 22 and the. condenser 20 are inclosed in a case 23 of con- 0 ducting material, which may be grounded as shown, and which is adapted to screen these parts of the P60611131 R from inductive influences of the transmitter T.

It will be understood that instead of inductively connecting or coupling the trans mitter T to the loop antenna A, such transniitter may be conductively connected or coupled to such antenna, as shown for example in Figure where the leads 25 and 26 of the transmitter are respectively con nected to the loop antenna A between the condenser 13 and inductance 15 and between the condenser 14 and inductance 16.

In a system such as the present one it is also desirable to provide means whereby the loop antenna circuit can be adjusted or balanced Without changing the wave length at which it is desired to transmit signals and to which the loop antenna has been tuned. W

In Figure 3, one way of accomplishing this purpose is shown, the same consisting in inductively connecting a short-circuited inductance 24 to the inductances 15 and 16 in such a way that it can be moved axially with respect to the inductances 15 and 16. Otherwise the system illustrated in Figure 3 is similar to the one illustrated in Figure 2.

Instead of inductively or conductively coupling or connecting the transmitter to the loop antenna system, a capacitive cou pling may be used, which is found to be desirable when transmitting on short wave lengths. One arrangement of capacitive coupling is illustrated in Figure 4 in which the loop antenna A includes condensers 27 and 28 substituted in place of inductances 15 and 16 of the systems of Figures 1, 2 and 8. The leads 251, 261 of the transmitter are connected to the loop antenna between such condensers 27, 28 and the condensers 131, 141, respectively, the latter being variable so that the loop antenna may be balanced to prevent interference between the transmitter T and the receiver R during their simultaneous operation. The open antenna branch circuit '13 is connected to both condensers 27 and 28 at a point 171 between said condensers, and otherwise the system of Figure 4 is in general similar to those of Figures 2 and 3.

Figures 5 and 6 illustrate other duplex radio transmitting and receiving systems wherein the loop antenna circuit may be adjusted or balanced without changing the wave length to which the loop antenna has been tuned. In Figure 5 the loop antenna circuit A includes two independent inductance coils 152, 162 between which is arranged a variable double condenser 30 of well known construction. The transmitter T has two coils 31 and 32 which are connected in series and inductively coupled to the coils 152 and 162. This arrangement is such that the loop antenna circuit is always balanced without changing the wave length, by means of the variable condenser 30, which has its movable plates connected to ground by the open antenna circuit B through the inductance 18 and condenser 20.

Figure-6 illustrates a system which is desirable when transmitting on short wave lengths and the same is arranged so that the loop antenna circuit A may be ad justed without changing the wave length at which it is desired to transmit signals. In the system of Figure 6 the loop antenna circuitA contains a variable double condenser 33 of well known construction that is connected to the condensers 133 and 1 13, which are also in the loop antenna circuit. The leads 253, 263 of the transmitter T are connected to the loop antenna circuit A between the condensers 133, 143 and the condenser 33, respectively. The movable plates of the double condenser 33 are connected to ground through the open antenna B and may be adjusted to a position to balance the loop antenna A for transmitting purposes.

It will be obvious from the foregoing that numerous circuit arrangements are possible which embody the broad principles of this invention, in which a simple and efficient radio system is provided for simultaneously transmitting and receiving waves or messages, without mutual interference. Therefore, it is to be understood that the present invention is not limited to the systems shown and described in the present drawing and specification.

What is claimed is:

1. A system of radio communication'comprising the combination of antenna means having a loop antenna including condensers and a grounded antenna connected to such loop antenna at a point between said condensers, transmitting means coupled to one of said antennas, and receiving means coupled to the other antenna.

2. A system of radio communication comprising in combination antenna means having a loop antenna including pairs of condensers, and a grounded antenna connected to such loop antenna at a point in balanced relation to said pairs of condensers, transmitting means coupled to one of said antenna means, and receiving means coupled to the other antenna means.

3. A system of radio communication comprising in combination antenna means including a loop antenna and a grounded antenna connected in circuit, transmitting means coupled to one of saidantennas, re* ceiving means coupled to the other antenna, and means for balancing said system without changing the wave length adjustment at which it is desired to transmit signals.

In testimony that I claim the foregoing as my invention, I have hereunto signed my name this 3d day of November A. D., 1919.

FRANS J. FRANSSON.

Images