US2541870A - Biconical high-frequency antenna - Google Patents

Description

Feb. 13, 1951 G. G. GREENE 2,541,870

BICONICAL HIGH-FREQUENCY ANTENNA Filed July 16, 1948 UNITED STATES PATENT OFFICE a I I B ICONI CAL HIGH-FREQUENCY ANTENNA 1 Gardiner G. Greene, Newton, Mass., assignor to The Workshop Associates, Incorporated; New- .ton Highlands, Mass a corporation of Massa-f 7 Fr et- Q l lfl'i l '1'Application'July'lfi,1948, serialNmsemli; g

zclaims; (01.250-33) Antennas for receiving high frequency telethin foil such as aluminum, copper orother con- Yision and frequency modulation signals are genducting material covers the outside of each o erally either "of'the-half wave dipole type or a the triangular pieces. simplev array comprising a dipole and a reflector To increase the mechanical strength and rigidmounted at as greata heightabove the ground ity of p the pyramidal structure, a poly Onally as possible. To obtain an optimum signal to shaped stiffening member, having a number of noise'pratio and to eliminate reflected signals, sides which corresponds withthe number of trisuch antennas 'must be carefully tuned, and angular pieces in the pyramidal structure, is ino'rientedafter: installation, an operation requiring serted within the structure with each of its sides the services 'ofxa skilledmechanicbecause of the 10 abutting the inner-surface of a'respective triancriticalness of such adjustments and the height gular piece; An ea-r projects from each respective above the ground-at which such adjustments are side of the polygonal member through a correnecessarily made: Being tu'nedto a single wave spendin aperture in he; abutting trian ular length, such antennas of the dipole type inher piece to fasten the polygonal member in position ently give poorer-performance on. all other wave within the. structure. The apex of the structure lengths so that it is often necessary to use sev-' is strengthened by a. conductingmember having eral-such"-"antennas to cover the television frea plurality of arms each-of which is attached to quency bands In order to avoid some of these dis the apex of a respectivetriangular piece thereby advantages-,th'e use of wide band antennas of insuring the electrical interconnection of the thezhorntype,hasjbeen proposed but-these sysgo foils. I w temsthave heretoforebeen quiteheavy, difficult to A'further feature of the invention is a conconstruct and install, and expensive. necting membervvhich may be a rod of insulating material with one end projecting through two holes located on the axis-of the pyramidal structure in the polygonally shaped member and :the

Objects of this invention are to provide a high frequency antenna of the biconical type which maintains a good impedance match to the transmission line over a'wide frequencyband, which conducting memb r r sp c v ly e pp si e is easily adjusted and oriented, which-can be inend of the connecting member'p qj through stalled indoors; which can be assembled and consimilarly located holes in the polygonally shaped nected without special tools or skill, which is light and conducting memb of a Second py dal in weight, which is inexpensive to construct, and tructure t reby o m i ta n th se S ructures which advances the art of antenna manufacture in axial al nm t'with th ap x s th r of in generally. spaced relationship. -'i:iInTa broad aspect the invention contemplates a se a d ot e j c s andasp c s Of t e in;

high frequency antenna comprising a pyramidal vention will be app from p fi m structure of insulating material with oneside 1106111116111? t f l l'IIa Wd l -1 8 d a f i 1 thereof covered by a-conductingfoil. The thickwhich ness of the foil is small relatively to the thickness Fig. 1 is arr-isometric I view of such embod i-:- of the insulating material so that the foil is supment; a ported thereby. In ;another aspect two such Fig. 2 is a plan view-of-two adjacent triangular pyramidal structures are maintained in axial '40 pieces showing one method of interlockingthem;

alignment with the apexes thereof in spaced re- Fig. ;-3 is anenlargedfragmentary cross sec- 7 lationship by a "connecting member of insulating tional view on line 3-3 of Fig-. 1; v I material. v v 4 l Fig. 4- is an elevation of the conducting meme In a specific aspect the pyramidal antenna her; and v structure comprises a plurality of triangular Fig. 5 is'a partial elevation ofthe polygonally pieces of insulating material for example fiber shaped stiffening member.

board or plywood; A plurality of tabs project "In Fig. ,1 are shown ;-two identical pyramidal from each of two respective sides of eachtriansupporting structures II with their axes in her-i; ular p ece- Eac sta has a fin erpr i g zontalalignmentzand .the pex he efi spar normally therefrom which is formed by a slot relationship. 3 Each of the structures It co n;- havingna side inralignment with the edge of the prises eight triangular pieces I2; of light Weight triangular piece-supporting thetab. Each slot insulating material-{for example corrugated fiber and finger engage a corresponding finger and slot board, positioned with their respective edges respectively on the adjacent edge of another of abutting to form aneight sided hollow pyramid said pieces,tnerebxiteeomp e -the; tr tu l; A wi h an penabasa .As i sh wnz n Fi .1.; .39.2.

outside of each triangular piece i2 is covered with a conducting foil [5, for example aluminum, the thickness of which is small relatively to the thickness of the fiber board so that the foil is supported thereby.

Two edges of each respective piece l2 are each provided with three tabs: l3 which interlock with the respective corresponding tabs on the abutting edges of the corresponding adjacent pieces. As is shown in detail in Fig. 2 each tab I3 includes a finger l4 projecting normally therefrom parallel to the adjacent edge of the piece [2. Each finger I4 is formed by a slot 16 one side of which is in alignment with the edge of the piece l2 sup-- porting the tab l3. The fingers on the respective edges of each piece [2 point in opposite directions. Two adjacent pieces l2 are interlocked by engaging the fingers M and the slots l6 of one piece [2 in the corresponding slots and fingers of the adjacent piece.

It is also possible to point the fingers IL on both edges of one piece i 2 in the same direction. When this is done the fingers [4 on both edges of each piece [2 must point in the opposite direction, the" fingers on adjacent pieces being directed in opposite directions. Although the above described methods of interlockin are preferred because of its simplicity and the ease or assembly, it is also possible to connect the piecess l2 b other well-known means, for example, staples, gummed tape or any of the various types of interlocking tabs or cars. I The apexes of the interlocked pieces l2 are fastened together by a metal conducting member I! which is inserted inside the pyramidal structure H. As is shown in Figs. 3 and 4, the conducting member I! has a plurality of arms I8 each of which is fastened to a respective triangular piece I! by aself tappin screw (9. The screws l9 project through holes. 2| (Fig. 2) near the apex of each of the triangular pieces 12 to engage the holes 22' in the respective arms I 8. A washer 23 is placed under the head of each screw Is to make contact with the foil I on each of the respective triangular pieces [2 to insure electrical interconnection of all the foils through the conducting member [1.

Further to reinforce the pyramidal structure II, a polygonally shaped stiffening member 24 of insulating material is inserted therein so that an ear 26 (Fig. 5) on each of the respective sides thereof projects through an aperture such as the slot 21 in each respective abutting triangular piece 12.

The pyramidal structures H are maintained in axial alignment with their apexes in spaced relationship by a connecting member of insulating material such as the wooden rod 28. One end of the rod rojects through the holes 29 and 3| axially located in the polygonal member and the conducting member respectively of one pyramidal structure H. The opposite end of the rods engage similarly located holes in the other pyramidal structure. A plastic collar 30 is attached at the center point of the rod 28 so that the apexes of the respective pyramidal structures l I cannot make electrical contact with each other.

" The antenna is located indoors at as great a height above the ground as practicable, for example, in an attic or under the roof of a garage. Assembly is preferably performed at the final location by laying out the triangular pieces l2 upon the floor with the foil t5 downwardly and then interlocking the adjacent pieces [2 by slid- 4 ing therespective fingers I4 and slots l6 into engagement as described above.

Before completing the final joint, the assembly should be lifted and formed into the eight sided pyramidal structure H with the apex thereof downward and the foil [5 on the outside. With the apex of the structure H resting upon the fioor, the cats 26 of the polygonal shaped reinforcing member are then inserted in the respective slots 21 in the triangular pieces I2.

The structure H is next turned over so that its base rests upon the floor and the conductirig member I! inserted inside the apex of the structure II and rotated so that the holes 22 in the arms l8 thereof are in alignment with the respective holes in the triangular pieces l2. The conducting member i1 is secured in this position by inserting one of the screws IS in each of respective pair of aligned holes. Before insertin each screw is a washer 23 is placed under the head thereof.

The second pyramidal structure it is assembled in a similar manner. To maintain the structures H in horizontal axial alignment the ends of the connecting rod 28 are inserted in the holes 29 and 3| of the respective polygonal stiffener and star shaped conducting member of the structures ll. Each of the wires of the lead-in cable 32 is clipped under a respective screw 19 in the apex of each of the pyramidal structures H.

When thus assembled the antenna is ready for use. Adjustment to give a maximum per'-. formance of the receiver is made by rotating the assembly about a vertical line through the colla 30 of the'rod 28.

Under some conditions most satisfactory results may be obtained by the use of a reflector such as indicated at 33 of Fig. 1, comprising a sheet of conducting foil, similar tothe covering foil [5, hung in a vertical plane parellel to and located approximately 3 /2 feet from the horizontal axis or the structures H. This distance is varied to obtain the optimum location where the best results without double images are ob-' tained. In some cases double images may be eliminated by rotating structures I I so that there is, a small angle between the axis thereof and the plane of the reflector 33.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A high frequency antenna comprising a plurality of triangular pieces of insulating material each with an aperture therein, a plurality of tabs projecting from each of two respective edges of said pieces, each tab having a finger projecting normally therefrom, said finger being formed by a slot having one side in alignment with the edge of the triangular piece supporting the tab, said slot and finger engaging the corresponding finger and slot respectively of the edge of another of said pieces thereby to com plete a pyramidal supporting structure, a thin conducting foil covering the outside of each of the respective triangular pieces, a polygonally shaped stiffening memberof insulating material with an ear projecting from each of the respec tive sides thereof to engage apertures in adjacent triangular pieces, and a conducting member having a lurality of arms each of which is fas i tened to the apex of one of the respective'trian 5 gular pieces thereby insuring electrical interconnection of said foils.

2. A high frequency antenna comprising two pyramidal structures each including a plurality of separate triangular pieces of insulating material, each piece having an aperture therein and a plurality of tabs projecting from each of two ger projecting normally therefrom, said finger being formed by a slot which has a side in alignment with the edge of the triangular piece supporting the tab, and each of said slots and fingers engaging the corresponding fingers and slots respectively on the adjacent edge of another of said pieces thereby to complete said structure; a thin conducting foil covering the outside of each of the respective triangular pieces; a polygonally shaped stiffening member of insulating material having a hole in the center thereof and an ear projecting from each of the respective sides thereof to engage the apertures in adjacent triangular pieces; a conducting member having a hole in the center thereof and a plurality of arms each of which is fastened to the apex of a respective triangular piece thererespective edges thereof, each tab having a fin- 7 byvinsuring electrical interconnection of said ;;foils; and a connecting rod of insulating mate-- rial having one end projecting through the respective holes in said connecting member and isa-id'fpolygonal member of one of said structures, fthejother rod end projecting through the respective holes in said conducting member and j -polygonal member of the other of said strucwares thereby to maintain the apexes of said 10 ;lstructures in axial alignment and spaced relationship.

GARDINER G GREENE.

REFERENCES CITED The following references are of record in the UNITED STATES PATENTS Num er Name Date 1 ,061,297 Johnson May 13, 1913 1,959 104 Ewers Mar. 6, 1934 2,267,889 Aubert Dec. 80. 1941 w 2,440,597 Atwood Apr. 27, 1948 2352.822 Wolf Nov. 2. 1948'

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