US2096501A - Antenna - Google Patents

Description

ct. 19, 1937. C, E, SCHULE-R 2,096,501y

i ANTENNA Filed Nov. 6, 1935 Patented Oct. 19, 1937 UNITED STATES PATENT OFFICE International-Stacey Corporation, Columbus,

Ohio, a corporation of h10 Application November 6, 1935, Serial No. 48,531

2 Claims.

This invention relates to the art of radio broadcasting and transmission of electromagnetic waves through space by means of a radio tower or vertical antenna radiator.

Such towers or radiators most commonly take the form of fabricated structural steel poles or masts which extend from the ground line to any desired height. At their lower ends, these masts are supported upon insulators in order to be electrically spaced from the ground foundation and, in addition, said masts may be formed so that they are inherently stable and of self supporting formation or in other instances are maintained in vertical order by means of lateral extensions such as guy wires.

In the practical operation of these towers, considerable energy is lost by radiation to the ground in the vicinity immediately surrounding said towers, and in my prior patent, No. 2,008,931 granted July 23, 1935, I have disclosed electrical means by which this normally lost energy may, to a very considerable extent, be returned to the vertical antenna for re-radiation, to the end of increasing the electrical efficiency of such antenna and their eective range of broadcasting.

It is the primary object of the present invention to provide an improved ground screen or collector over that disclosed in my above referred to prior patent to increase both its mechanical and electrical factors of eciency and to reduce cost and simplify the installation thereof in connection with any type of vertical antenna radiator.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawing, wherein:

Fig. il is a view in side elevation of a vertical radial antenna provided with the ground screen comprising the present invention;

Fig. 2 is an enlarged vertical sectional view taken through the ground screen and the associated lower portions of the antenna;

Fig. 3 is a horizontal sectional view on the plane indicated by the line III-III of Fig. 2.

Referring more particularly to the drawing, the numeral l represents a tower formed of structural steel members and reenforcing struts and girders, providing a four-cornered tower with a broad base tapering to a narrow top. While this type of tower has been selected for purposes of illustration, it will be understood, as the description proceeds, that the features of the invention are applicable to structural steel radiators or antenna of any other desired configuration. In this instance, the lower end of the tower is supported by insulators 2, which are secured upon the upper surfaces of concrete foundation piers 3, which are embedded in the ground adjacent to the tower.

In carrying out the present invention, the up- (Cl. Z50-33) per surface of the ground, contiguous to the piers 3, is preferably excavated to a depth of several inches to receive a bed of gravel, indicated at 4, on the top of which is laid a metallic, horizontally disposed screen 5. This screen is substantially rectangular in configuration and in the event the tower l is approximately 125 ft. high, the screen may advantageously be 20 ft. square. 'Ihe gravel bed 4 is preferably treated with tar in order to supress vegetation. Electrically connected with the margins of the screen 5 are a plurality of horizontally extending wires 6 which project radially from the center of the tower l and are placed ordinarily six inches below the ground line. These Wires extend approximately 125 ft. from the marginal edges of the screen 5 and constitute a part of the collector system.

In accordance With the present invention, the ground screen provides a highly conductive surface below the antenna tower, at which the electro-static lines emanating from the base of the tower terminate, thereby providing a low resistance surface. In the present instance, the ground screen is not supported by the antenna tower, but lies at its base and is insulated therefrom. The screen described provides in combination with the antenna an electrical system that reduces to a negligible amount the power loss that would normally occur at the base of the antenna tower, and it is particularly useful in the matter of decreasing the height of such towers without loss of broadcasting range.

What is claimed is:

1. In an antenna system, a vertical radiator, a foundation pier extending into the ground for supporting said radiator, a supporting insulator disposed between said pier and the lower end of said radiator, a prepared bed incapable of supporting plant life, such as gravel and tar or the like, formed in the ground and surrounding said pier below said radiator, a ground screen resting on said bed in centralized relationship with but spaced from said radiator, and a plurality of conductor wires embedded in the ground and extending radially from the marginal edges of said screen in substantially the same horizontal plane as the screen.

2. An antenna system comprising a vertical tower mounted on insulating supports, a prepared bed incapable of supporting plant life, such as gravel and tar or the like, provided in the ground surface below said tower, a flat horizontally disposed mesh conductor placed upon the bed beneath the tower and in spaced relation from the latter, the said mesh conductor possessing an area materially in excess of that of the plane configuration of the lower end of the tower, and a plurality of ground wires connected with and radiating from the marginal edges of said conductor.

CHARLES E. SCI-IULER.

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