US1719893A - Loop for radioreoeption - Google Patents

Description

9, 1929. I R H, LANGLEY. 1,719,893

I LOOP FOR MDIOREOEPTIO` File March 29, 1924 Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

RALPH I-I. LANGLEY, OF SCHENECTADY, NEIV YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

LOOP FOR RADIORECEPTION.

Application filed March 29, 1924. Serial No. 702,944.

My present invention relates to the type of antenna for radio reception known as a loop, and more particularly to loops which are adapted to be readily rotated and are of a size convenient for indoor use.

One of the objects of my invention is to provide an etlicient form of receiving loop which may be easily constructed. A further object of my invention is to provide a loop which will have a maximum efficiency for a predetermined maximum available space and maximum predetermined value of inductance.

An indoor loop antenna must las a reasonably small structure and should be arranged preferably to rotate on a vertical axis through an angle of at least 180 degrees. The total space required for the loop'therefore is an imaginary vertical. cylinder whose diameter is the horizontal dimension of the loop, and whose height is the vertical dimension of the loop. In the past loops have usually been constructed in substantially flat form with more or less concentrated windings. The turns are usually wound quite close together sometimes being separated only by the insulation on the wire itself. "With such a.

winding the inductance is very closely proportional to the square of the number of turns. quite definitely limited by the fixed value of the inductance which cannot be exceeded if the desired range of wave lengths for. which the loop is to be employed is to be covered.

Since the loop requires for its rotation all of the space occupied by the imaginary cylinder mentioned previously, the space required for the loop will not be increased if the turns instead of being fairly close together as in other constructions, are spaced apart and distributed around the circumference of the imaginary cylinder. I have found that by spacing the turns in this way a loop which will operate in a given space may be made much more efficient than when the turns are concentrated, or the spacing between turns is very small. lVhen the turns are spaced in this way it will be found that the inductance of the winding is no longer proportional to the square of the number of turns, but that the loop may have several more turns than a concentrated winding before the fixed value of the inductance is reached. In the conventional type of loop Where the turns are close together and all of the same size or nearly so the area inside et the turns is a fair measure The number of turns therefore is of the pick up value of the loop. Forexample, a loop 48 square would have an area of 2,304 square inches, while a loop 33 square, or 30 per cent smaller, would have an .area of only about 1,089 square inches and would be less than half as effective. lVhen the turns are spread out, as described, the pick up value is no longer proportional to the area. In the lirst place the turns no longer all have the same area and in addition several extra turns are obtained forthe same value of inductance. The pick up measure of such a loop is more nearly proportional to the turn-area, that is the number of turns multiplied by the average area included in each turn.

In a radio receiving set with proper amplifrcation it will be found that a loop having certain value of turn area will give satisfactory performance. A larger loop will not give any greater distance or stronger signal. The chosen size will be large enough to receive any signal which has a reasonable ratio to the air noises and set noises which limit the range and sensitiveness of every receiver. I have found that a spaced turn cylindrical loop having the same turn area and inductance as a flat loop of the usual type having the necessary turn area to operate the receiver, can be made which will require for its operation less than one-third the space of the fiat loop. The spaced turn loop of cylindrical form has the additional advantage that on account of the spacing of the turns the losses are from onehalf to one-third as great as in the equivalent flat loop. These low losses not only permit much greater sensitivity'or sharper tuning, but also increase the effectiveness of the loop as a pick up device.-

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims.` My invention itself, however', both as to its organization and method of operation will best be understood by reference to the following description taken in connection with the accompanying drawing in which I have shown in perspective one form of my invention.

I have shown in the drawing a loop which is wound over two end supports of substantially circular" form. These supports each comprise two segments of rings l and 2, which are secured. to a central cross bar 3 by means of 'rods 4;', The two end supports are held in soV spaced relation by means of four spaced vertical rods 5 and a central rod 6, which serves as a shalt. The ends of this sha'i't 6 are supported by bearings 7, which in turn may be secured to a su pporting structure in any desired Way.

The turns ol the loop are Wound over this Ylorin, as indicated, the vertical portions torming elements of the iii'iaginary cylinder and the ends ot the loop are secured to the central cross bar 3 ol? the top support and connected to two rings 8, ol conductive material, which are mounted on the shaft (5. l? rushes 9, which bear upon these rings S serve to Iconduct the current received on the loop to the receiving set. An end gear l() may be secured to the shalt 6 and the loop rotated by means of a pinion l1, which meshes with the bevel gear l0, and which is secured to a shaft ll, having at its end an operating knob 12. The loop may be incased in the lower part ot' a cabinet of a receiving` set and the sna'lit ll extended through the panel on the set. A pointer 13 may be secured to the operating knob l2 to indicate on a convenient scale the direction of orientation ot the loop.

In the device illustrated the vertical por` tions of the turns oit the loop are distributed over approximately 240 degrees ot the eircumierence of the inniginary cylinder. This is about the maximum portion of the circumference ot the cylinder vvhich ycan be used to advantage as the horizontal dimension of the lfeiv additional turns Which could be obtained by covering a larg'eportion ot the circumference would be too small to be ot much advantage for reception. It Will ot course be apparent that some olf the advantages ot' my invention may be obtained With the turns of the loop distributed over a. smaller portion or the circumference of the cylinder.

The torni upon which the loop is Wound is preferably constructed entirely of insiillating material and fastened together Without the use ot any metal securing,` devices, as the use ot any metal Within the loop introduces losses which should be avoided.

lV hat I claim as new and desire to secure by Letters Patent ot the United States, is,-

l. A receiving loop for radio reception comprising a plurality of spaced turns of Wire ot ditl'erent horizontal dimensions so arranged that the vertical portions of a plurality olf turns form elements oit a single cylinder and none ot the horizont-al port-ions otA the turns cross a horizontal portion of another turn.

2. A receiving,r loop for radio reception comprisingr a plurality ot spaced turns of Wire of di'li'erent horizontal dimensions so arranged that the Vertical portions of the turns lorm elements ot a cylinder, and are distributed over at least ninety degrees of the circumference of the cylinder and that no horizontal portion of a turn crosses a horizontal portion of another' turn.

A receiving; loop for radio reception con'iprisino` a plurality of spaced turns of wire of different horizontal dimensions so arranged that the vertical portions of the turns 'form elements of' a cylinder' and are distributed over approximately two-hundred and forty degrees oi the circumference ol the cylinder and that no horizontal portion ot a turn crosses a horizontal portion of another turn.

4f. A loop for radio reception com prising a plurality of spaced turns of wire ot different horizontal dimensions so arranged that the vertical portions of a plurality ol.t turns 'forni elements ot single cylinder having' a diameter substantially equal to the horizontal diniensions oit the turn having' the greatest horizontal dimension and that no horizontal portion of a turn crosses a horizontal portion ot another' turn.

5. A receiving` loop for radio reception adapted to be mounted to rotate within a cabinet comprising a plurality ot spaced parallel turns of Wire of ditlerent horizontal di ensions so arranged that the vertical portions oit all of the turns form elements ot' a single cylinder having; a diameter substantially equal to the horizontal d' ncnsion of the turn having the greatest horizontal dimension and that no horizontal portion ot a turn crosses a horizontal portion oi another turn.

(E. A receiving loop lor radio reception comprising1 a plurality of turns ol" Wire of d illlerent horizontal dimensions so arranged that the vertical portions of the turns form elements of a cylinder and are distributed over at least ninety degrees ot the circumference of the cylinder, each oit said turns being spaced from the turns adjacent thereto by a distance materially greater than the diameter of the Wire, and the horizontal portions of said turns being` so arranged that no horizontal portion olf-a turn crosses a horizontal portion ot another turn.

In Witness whereof, 1 have hereunto set my had this 28th day ol March, 1924.

RALPH H. LANG-LEY.

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