US 1799576 A
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Patented Apr- 7, 1931 J UNHTED STATES ERNEST WILDHAIBER, or ROCHESTER,' NEW YORK METHOD 0E EMITTING mm smmm Application filed July 16,
My invention relates to methods of emitting signals'by radio, that is by wireless telegraphyor wireless telephony.
One main object is to guide ships and to prevent their collision. 'A further object is to emit radio signals which are strong at .close range but vanish rapidly at increasing distances. A still other aim is to provide a method of emitting radio signals decreasing in strength so rapidly at increasing distances, that the distance between sender and receiver can be dependably determined by the strength of the received signal. Another object is to provide an antenna for carrying out my method. y Y
In explaining my invention, reference is made to the accompanying drawings, in which I Fig.1 is a schematic view of an antenna for carrying out my method; 7
Fig. 2 is a view of a slightly. modified antenna; I
[Fig 3 is a schematic view of another modified antenna;
7 Fig. '4.- is axdiagram explaining the nature of my novel method of emitting radio sig-' nals; H a
Fig. 5 is a diagram supplementing Fig. 4. Fig. 6 is a front View of a preferred embodiment of my invention, leaving out known details;
Fig. Fig. 6.
Fig. 8 is a plan view of a slightly modified embodiment. r
Signals for guidance of ships and for preventing collision hitherto have been'produced 7 is a plan view corresponding to mainly by way of light and by way of sound.
The former is not dependable in mists and fogs, and the latter has not'sufiicientreach, in addition to reminding passengers every minute of the risks they run.
Radio signals have not been used hitherto in this way and for this purpose, as far as I am aware. Radio signals of usual type carry too far, and therefore too many signals could be heard at'a'time, which would result in confusion. If'made so Weak'as to carry only a short distance they are not de* pendablei produced whose strength "decreases much is required, when the various ships send out signals of the same wave length. The sigorder to be seen, must be in the directionof 1925. Serial no. 44,025.
It is an object of the present invention to produce a radio signal, which is strong at short distances, but nevertheless does not carry far. In other words,- a signal shall be more rapidly at increasing distances, than usual radio signals; This will be done without'resortmg to inconvenient wave lengths,
as will be more fully disclosed hereafter;
Such signals may be emitted at the same' wave lengths by diflerent ships, and also land stations, and preferably with equal strength.
Distant ships will not notice respective signals, on account of the vanishing nature of the new signals. When however two ships come close to each other, respective signals will be received, in clear or misty or foggy weather, and the ships are thus aware of their close presence. It is noted that no tuning in nals are therefore received automatically, in
a way even superior to a light, which, in
look of the observer. 1
Moreover the distance between two ships can be measured by the intensity ofthe receivedsignal; and if so desired the direction of a ship with respect to another can be. determined in known manner, forinstance with a coil receiver. I
in wire 11, a current of about equal'strength flows downward in wire 12. The waves transmitted to the ether by the two wires 11 and12 are therefore of opposite phase.
The arrangement of Fig. 2 differs from the one indicated in Fig. -1 merely by. contain- "ing tubes 15, 16 instead of the wires 11 and 12. The tubes areconcentric with a mast 17,
which serves to hold them in place.
Fig. 3 indicates a cage of wires in place of a single wire. The different wires 18, 19, 20, 21 of the upper cage 22 are connected in paralleL-that is current flows in the same direction in all of them. Similarly the wires 23, 24, 25, 26 of the lower cage 27 are also connected in parallel. Radio impulses are applied by a wire 28 in any suitable known The action of the above arrangements and of the subsequent arrangements will now be explained with reference to Fig. 4 and Fig. 5. These figures are in part a repetition of Fig. 1, as representing a very simple em; bodiment of my invention. I
30, 31 are two points equidistant trom point 32, at which the lead in Wire 33 is attached. 34 represents the sea level, or broad'-' ly a horizontal direction. At a point 35, which has the same distance from either point and 31, radio waves of exactly opposite phase arrive from the directions 36, 37 respectively. If these waves of opposite phase and equal strength would have the same direction, they would wipe out each other. The directions 36, 37 are however at an angle 38 with respect to one another, so that the individual waves combine to a resultant wave whose strength is in proportion to angle 38, aside of being proportional to the strength of an individual wave at point 35.
Angle 38 decreases with increasing distance of point from points 30, 31, so that the strength of a resultant wave decreases much faster than the strength of an individual wave, that is of a usual radio wave. As has been previously pointed out, this is one of the principal aims of my invention. By suitably dimensioning the sending antenna and by applying suitable power, signals can thus be produced, which are strong atclose range but which vanish rapidly at a distance.
According. to my method an increasing degree of interference is thereforeproduced at increasing distances.
Fig. 5 refers to a point 40 which hasslight- 1y different distances 41, 42 from symmetrically placedpoints 30, 31. In this case the waves coming from 30 and those coming from 31 are not of exactly opposite phase, the difference from opposite phase corre sponding to the difference of the distances 41, Since however this difference, as well asangle 43 decreases at increasing distances, seepoint 44, the resultant waves decrease in the same rapid manner as inpoints 35, Fig. 4.
Inreducing my method to practice, it is to be kept in mind that the lead inwire (10 in Fig. 1 should not disturbthe action of the opposite Wirings (1'1 and 12 in Fig. 1). One way of practically eliminating the influence of aleadin wire 10) is to put a small sending set asv a whole with metal enclosing between the two Wirings (11 and 12).
The two opposite wirings may be. accurate- 1y balanced to emit waves of exactly equal strength, by slightly changing the location e d i w e (10.) s indicat d n F g- 1 a Fig. 1 also outlines means for controlling the emitted waves, to produce signals. These means may consist of a buzzer circuit 46 of known character, which is inductively coupled with the antennae 11, 12, by means of coils 47 48. Coil 47 or a plurality of such coils form an inductive connection between the electric capacity constituted by the antennae and the electric capacity constituted by a ring 49, thus making the whole an oscillatory system. When key 46' is depressed, the battery circuit is periodically closed and opened in known manner and oscillations are periodically induced in the oscillatory system of which the antennae form part.
Fig.- 6 and Fig. 7 indicate an adaptation of my invention to the coil type of antenna, which permits closed electric circuits. Inasmuch as in most applications of my invention itisdesirable to send out non directions al signals, that is signals of equal strength in every direction, a plurality of angularly displaced coils 50, 51 is provided, to offset the directional qualities of single coils. In the embodiment of Fig. 6 and Fig. 7 two systems 52, 53 of coils are used, which consist of two single coils each. The two systems. are preferably symmetrical, insucha way, that electric current of the same strength flows oppositely in the two systems, so that radio waves increasingly interfere at increasing distances,
Figs. 8 outlines a system of three double coils. 54, 55, 56 grouped around a mastv 57.
Preferably periodical signals are used, and automatically emitted. They may consist of dots and dashes, that is of abrupt and prolonged sounds, or'they mayconsist of words and then may be reproduced by phonographs. In all cases they arecarried by radio waves.
It isunderstood that such changes and modifications may be made in my invention, as fall within the. limits of the appended claims.
hat l m s:
1. A method of emitting radio signals for guidance of ships, which consistsin radiating electromagnetic waves, the waves radiated inhorizontal direction containing magnetic induction lines of horizontal general direction, in simultaneously radiating waves of the same character and of the same intensity from another place, in changing the amplitude. of said waves, thereby emitting signals, and in maintaining the twosystems of waves continuously-in opposite phase, so as to cause increasing interference at increasing distance.
2. A method of emitting radio signalsfor guidance of ships, whichconsists in radiating electromagnetic waves, the waves radiated in horizontal. direction having-magnetic induction lines of horizontal general direction, in simultaneously radiating other waves of the same character, and the same intensity asthe first said waves, said other waves being radiated from another place, in periodically changing the amplitude of said waves, thereby emitting periodical signals, and in maintaining the two systems of waves continuously in phase opposition, so as to cause increasing interference at increasing distance.
3. A method of emitting radio signals for guidance of ships, which consists in radiating electromagnetic waves uniformly in all horizontal directions, the waves radiated in horizontal direction having magnetic induction lines of horizontal general direction, in simultaneously radiating other waves of the same character and the same intensity as the first said waves, said other waves'being radiated from a different place, in periodically changing the amplitude of said waves, thereby emitting periodicalsignals, and in maintaining the two systems of waves continuously in phase opposition, so as to cause increasing interference at increasing distance.
4:. A method of emitting radio signals for the guidance of ships by the use of two vertically displaced antennae, which consists in periodically radiating electromagnetic waves uniformly in all horizontal directions by effecting alternating currents in said antennae, the waves radiated in horizontal directions having magnetic induction lines of horizontal general direction, and in maintaining the currents in the two antennae continuously in phase opposition, so as to cause increasing interference at increasing distance.
5. An antenna for emitting radio signals, comprising two parts vertically displaced with respect to each other and symmetrically disposed with respect to an intermediate horizontal plane, said parts being of vertical gen eral direction, and means for maintaining electric current in said two parts in opposite phase.
6. An antenna for emitting radio signals, comprising two parts vertically displaced with respect to each other, said parts being of vertical general direction and being connected in parallel with a lead in wire, so as to maintain electric current in said two parts in opposite phase.
7 An antenna for emitting radio signals, comprising two parts vertically displaced with respect to each other, each of said parts being of vertical general direction and being substantially symmetrical with respect to at least four vertical planes passing through the vertical center line of said part, and means for maintaining electric current in said two parts in opposite phase.
8. An antenna for emitting radio signals, comprising two parts vertically displaced with respect to each other, each of said parts being of vertical general direction and being substantially symmetrical with respect to at least four vertical planes passing through the vertical center line of said part, and a lead in wire connected in parallel with said parts.