US 3419872 A
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Description (OCR text may contain errors)
De@ 31, 1968 w. E. sT. vRAlN ET AL 3,419,872
DIPOLE ANTENNA HAVING COAXIAL CABLE ARMS CAPACITIVELY COUPLE'D TO SPACED TUBULAR RADIATORS Filed June 2s, 196e United States Patent C) 3,419,872 DIPOLE ANTENNA HAVING CDAXIAL CABLE ARMS CAPACITIVELY COUPLED T SPACED TUBULAR RADIATORS Wallace E. St. Vrain, Kirkwood, and Joseph J. Mandino, Bridgeton, Mo., assignors to Mosley Electronics, Inc., Bridgeton, Mo., a corporation of Missouri Filed June 23, 1966, Ser. No. 559,817 3 Claims. (Cl. 343-792) This invention relates to a beam antenna of extremely simple and inexpensive construction, incorporating means to improve the resistance of the antenna, permitting longer antenna elements by decreasing the reactance of the elements. Specifically, the object of the Iinvention is to provide a beam antenna having one or more antenna elements with the usual coaxial cable connection for transmitting the pickup signal to a receiver, and with coaxial cable extensions through the hollow antenna element to decrease the reactance of the antenna, thereby permitting increased length of the antenna elements and resultant increased resistance. A general object of the invention, therefore, is to provide a beam antenna incorporated with extremely inexpensive and simple means for decreasing the reactance of the antenna element, to permit increasing the length of the elements to increase the resistance for improved reception.
Other objects and advantages will be apparent to those skilled in the art.
The drawing is a fragmentary view in longitudinal medial section through a typical single element antenna showing the connections for the improved resistancereactance characteristics of the antenna,
While this invention is particularly described in connection with a single element antenna, it will be appreciated by those skilled in the art that its features and advantages may be incorporated in any multi-element antenna.
As shown in the drawing, the antenna i8 has a conventional element support 9 mounted through any conventional aluminum 'clamping block 10 by a U-bolt 11 to a conventional Iboorn 12. An electrically non-conductive matching tube and connector 13 is hollow with open ends 14 and 15 into which antenna or wall elements 16 and 17 are received. The wall elements 16 and 17 are mounted on insulators 18. Screws 19 extend through the wall elements 16 and 17 and into the insulator 18 and other screws 20 from the underside of the element support 9 to fasten the parts together as is clearly illustrated in the drawing.
An electrically conductive connector 22 having an externally threaded base 23 is attached through -an opening 24 in the lower central wall of the matching tube and connector 13. The connector 22 has a passage'25 through it in which an insulating grommet 26 is received. An electrically conductive terminal strip 27 is secured in the grommet 26.
A conventional coaxial cable 28 having a central hot wire 29 surrounded by an insulating sleeve, a meshed ground conductor 31, and an outer insulating cover 32 is connected to the terminal strip 27 and the body of the connector 22. The hot wire 29 is tightly fastened to the terminal strip 27, while the ground conductor 31 is tightly fastened and secured to the body of the connector 22. The other end of the coaxial cable 28 is con- :nected to the receiver or transmitter (not shown).
According to this invention, another conventional cable 33 has its central wire 34 soldered to the upper end of the terminal strip 27 and extends through the wall 3,419,872 Patented Dec. 31, 1968 element 17, and a separate cable 35 has its central wire 36 soldered to the connector 22 and extends through the other wall element 16.
The result of extending the coaxial cables 33 and 35 through the antenna elements 16 and 17, with the cable 33 connected directly to the hot wire 29 of the cable 28 through the terminal strip 27 and the cable 35 connected through the connector 2.2 to the ground conductor 31, is to de'crease the reactance of the antenna and permit greater resistance. This means that the antenna elements 16 and 17 (along with the usual extensions and trap assemblies) may be lengthened over what is standard for antennas. Consequently, the gain of the antenna is greatly improved and stronger signals are received by the receiver. For example, by extending the cables 33 and 35 through approximately three-fourths the length of the respective antenna elements 16 and 17, the total length end to end between the left end of the antenna element 16 (and its extensions and trap assembly) and the right end of the antenna element 17 (and its extensions and trap assembly) can be 25 ft. 4 inches for the redector element, 25 ft. 2 inches for the radiator, and 20 ft. 8 inches for the director. Yet, this result is achieved with inexpensive parts simply constructed and installed.
Various changes and modifications may be made within the purview of this invention as will be readily -apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as dened by the claims appended hereto.
What is claimed is:
1. An antenna assembly comprising a support, a central hollow tube having open ends, a first antenna element received within one open end of the hollow tube, a second antenna element received within the other open end of the hollow tube, both antenna elements being hollow and being supported with the hollow tube on the antenna support, a rst insulated conductor extending through a substantial portion of the length of the first antenna element, a second insulated conductor extending through a substantial portion of the length of the second antenna element, forming a capacitor between conductor and element, a coaxial cable, the coaxial cable having the conventional hot line and ground conductor separated by insulation, first means for connecting the first conductor to the hot wire of the coaxial cable, and second means insulated from the first means for connecting the second conductor to the ground conductor of the coaxial cable.
2. The antenna assembly of claim 1 wherein the second means comprises an electrically lconductive plug-like connector threaded through the wall of the hollow tube, the second conductor and the ground conductor of the coaxial cable being soldered to the plug-like connector, and the first means comprises an electrically conductive strip supported by an insulator which in turn is supported by the plug-like connector, the first conductor and the hot wire of the coaxial cable being soldered to the strip.
3. The antenna assembly of claim 1 wherein the first and second conductors are coaxial cables.
References Cited UNITED STATES PATENTS ELI LIEBERMAN, Primary Examiner.
U.S. Cl. X.R. 343-802