US2115788A - Ultrashort wave system - Google Patents

Description

May 3, 1938. H SCHARLAU ULTRASHORT WAVE SYSTEM Filed May 14, 1956 INVENTOR HANS SCHARLA-U 7%? m' L/ ATTORNEY RECEIVER Patented May 3, 1938 UNITED STATES ULTRASHORT WAVE SYSTEM Hans Scharlau, Berlin, Germany, assignor to Telefunken Gesellschaft fur Drahtlose Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application May 14, 1936, Serial No. 79,634 In Germany June 8, 1935 2 Claims.

The present invention is concerned with an arrangement adapted to receive electrical waves, especially ultra short waves, from all directions.

In order to insure reception of electromagnetic waves from all and any direction it has been customary in the prior art to use for the receiving aerial simple wires and dipoles, and for the reception of greater energies wires of a length equal to several waves, and also rows of dipoles.

In order to pick up uniform volumes of energy from all directions, it is necessary that the said antenna arrangements be mounted vertically.

Of course, it will be feasible only in this way to pick up vertically polarized waves. If, for one reason or another, horizontally or obliquely polarized waves are also to be received, the said arrangements of the prior art fail to operate.

1 According to the present invention, waves com- I ing in from different directions and polarized in various ways can be picked up by the aid of a conical reflector which reflects them onto a receiving arrangement which is fundamentally known in the art and which is responsive to waves of any direction of polarization. Such an arrangement, for instance, may consist of two crossed dipoles which are caused to act upon the receiver with a phase displacement angle of 90.

Figs. 1 and 2 show two different embodiments of the invention.

Fig. 1 shows an arrangement of this invention for waves coming in from different directions and which is built into a railway car. K is a coneshaped reflector which will reflect a wave com- .ing in from any transmitter S at all into the interior of the car by way of the parabolic reflector Sp onto the crossed dipoles D which are united with the receiver E. Since a conical reflector is built circularly symmetrical, the waves may come in from all possible directions. By means of the Z crossed dipoles, the directions of polarization of the incoming waves are immaterial for effecting reception.

Fig. 2 shows a similar embodiment by way of example. In the power propelled car A, in the focus of the concave mirror Sp, is disposed the dipole cross D which is associated with the receiver E. In lieu of the cone reflector K of Fig. 1, there is provided a rotary reflecting structure 7 F similar to the lift screw or propeller of a l helicopter type airplane. The reflecting vanes or blades I, 2, 3 4 and 5 could, for instance, be cut out of a conical shell, but the breadth of the constituent vanes at the reflecting points must be at least equal to M2 in order that they may also reflect horizontally polarized waves. The rev lows: From a transmitter S a wave-train, say,

unmodulated in nature, shall be assumed to strike one of the vanes of the mirror wheel F and is thus reflected into the interior of the car A. Inasmuch as the wheel revolves, the vanes continue rotating and the wave-train no longer 5 reaches the receiver. Then the second vane becomes efiective and operative, and so on. The result is that brief impulses of waves are received which act in such a fashion as though the transmitter were modulated at a frequency which 10 is equal to the rate of rotation per second of the vaned wheel multiplied by the number of the vanes. Also, in the case of this arrangement it is, fundamentally speaking, immaterial from which direction the waves impinge upon the 15 vaned wheel or reflector wheel. A considerable advantage results also in that the incoming wave by the modulation of the reflector wheel is completely modulated.

Of course, the embodiments hereinbefore shown 20 and described do not exhaust the basic idea of this invention. For example, in lieu of a coneshaped reflector also a pyramidal reflector could be employed which, in addition, could be rotatable. Also, for the receiving aerial to pick up the waves, recourse could be had to other dispositions, say, a "Christmas tree type of aerial, although crossed dipoles would have to be used in the latter rather than individual dipoles or else two crossed Christmas tree type antennae in order to render the assembly independent of the polarization of the incoming waves.

What is claimed is:

1. In combination, in a short wave receiving system, a reflector in the form of a cone, said re- 35 flector comprising a plurality of spaced reflecting blades arranged in the surface of said cone, said reflector being rotatable around the axis passing through the apex thereof, whereby the waves impinging on said reflector are modulated at a 40 frequency which is a function of the rate of rotation of said reflector and the spacing of said blades, and an arrangement substantially symmetrically positioned with respect to the 'apex of said conical reflector for receiving waves of any 5 polarization impinging upon the blades of said conical reflector.

2. In combination, in a short wave receiving system, a. reflector in the form of a cone, said reflector comprising a plurality of spaced reflecting 50 blades arranged in the surface of said cone, and an arrangement substantially symmetrically positioned with respect to the apex of said conical reflector for receiving waves of any polarization impinging upon the blades of said conical re- 55 flector, said blades having a width at one portion at least as wide as half the length of the communication wave.

HANS SCHARLAU. 60

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