US2834015A

US2834015A - Television antenna

Info

Publication number: US2834015A
Application number: US464693A
Authority: US
Inventors: Douglas H Carpenter
Original assignee: JFD Manufacturing Co Inc
Current assignee: JFD Manufacturing Co Inc; JFD MANUFACTURING COMPANY Inc
Priority date: 1954-10-26
Filing date: 1954-10-26
Publication date: 1958-05-06
Anticipated expiration: 1975-05-06

Description

May 6, 1958 D. H. CARPENTER TELEVISION ANTENNA Filed 001:. 26, 1954 2 Shee ts-Sheet 1 J. .1- .l 2.1. 4'6 T :1 90

F40 5Z 56 E 1 57 5. /Z :i 6 $4 v I INVENTOR DOUGLAS 64 ChePENTER ATTORNEY Filed 001',- 26, 1954 D. H. CARPENTE-R TELEVISION ANTENNA May 6, 1958 2 Sheets-Sheet 2 INVENTOR ATTORNEY TER United States Patent :1

TELEVISION ANTENNA Douglas H. Carpenter, Brooklyn, N. Y., assignor to JFD Manufacturing Company, Incorporated, Brooklyn, 7 N. Y., a corporation of New York Application October 26, 1954, Serial No. 464,693 2 Claims. (Cl. 343-876) The present invention relates to an improved receiving antenna and it relates more particularly to an improved adjustable television receiving antenna suitable for indoor use.

The requirements for a good antenna, particularly that used in television reception, is that it be capable of re ceiving the desired signal to the substantial exclusion or the relative attenuation of other and spurious signals and to the exclusion of the same signal traversing a different path, that it have good gain characteristics of the desired signal and that it be capable of efliciently delivering the signal to the transmission line without the introduction of additional time delayed signals. In order that the antenna pick up the desired signal at its maximum strength and Without the interference of other signals or without picking up the same signal displaced in time to cause ghosts the antenna should have good directivity and be capable of adjustable orientation. While stacked arrays and antennae provided with directors and reflectors are superior in this respect, the simple dipole is highly satisfactory particularly in relatively strong signal areas and possesses the advantage of compactness, which permits its indoor use and the simple manipulation for the proper orientation thereof. As to the relative gain of the various antennae, the stacked arrays and those provided with directors and reflectors are generally higher than the simple dipole. However, they are extremely bulky and are not adopted for indoor use. Moreover, they are not readily adaptable to tuning by means of length adjustment, as is the simple dipole, and hence are of varying gain characteristics, frequently below that of the correspondingly tuned dipole. Thus the simple dipole of adjustable length readily lends itself to indoor use, specifically for the reception of television signals, since it is compact, readily tunable by the adjustment of the length thereof and easily directed. However, with the advent of color television the requirement that the signal be faithfully and efiiciently delivered to the transmission line has assumed great importance. In order to effect such transfer of the signal it is necessary that the antenna be matched to the transmission line. Not only does a mismatch result in an attenuation of the transmitted signal but more important the discontinuity caused by the mismatch results in multiple reflections and consequently in ghosts. While these ghosts, under normal circumstances in black and white television are only slightly spaced and effect the definition of the picture in only a minor degree, in the case of colored television, the observed undesirable results are appreciable, reducing definition and color fidelity. It is thus important that a relatively good match be achieved between the antenna and the transmission line. The transmission line usually employed in television reception is the so-called two-wire flat ribbon line or its equivalent, being a balanced line having a nominal 300 ohm impedance but usually somewhat less in commercial availability, of the order of 270 ohms. In order to achieve a good match between the antenna and the conventional 300 ohm transmission line it is necessary that the out-'.

put impedance of the antenna system be always adjustable about the three hundred ohm range at the various frequencies to which the antenna is tuned.

It is thus a principal object of the present invention to provide an improved antenna.

' Another object of the present-invention is to provide an improved indoor receiving antenna.

Still another object of the present invention is to provide an improved indoor television receiving antenna.

A further object of the present invention is to provide an improved indoor television receiving antenna simply tunable to resonate at selected frequencies.

Still a further object of the present invention is to provide an improved portable television antenna capable of being matched to a transmission line over a wide range of frequencies.

antenna constituting a preferred embodiment of the present invention;

Figure 2 is an enlargedsectional view taken along line 2 --2 in Figure 1 with parts broken away for convenience of illustration;

Figure 3 is a sectional view taken along line 3-3 in Figure 2;

Figure 4 is a sectional view taken Figure 2;

Figure 5 is a detailed sectional view taken along line 5 5 in Figure 4; and

Figure 6 is a schematic wiring diagram of the improved antenna.

The present invention broadly contemplates the provision of an improved antenna comprising a base member, a pair of separated antenna elements of adjustable length carried by said base member, a pair of parallel open: ended tuning elements of adjustable length each of' said tuning elements being coupled to a corresponding antenna element and a transmission line having a pair of Y conductors each of said conductors being connected to a respective set of antenna element and tuning element.

In accordance with a preferred embodiment of the present invention the base member is substantially heavy and supports a pair of upright brackets preferably formed -of an insulating material and provided with confronting cavities which define a housing. The brackets are of cup-shaped configuration their open ends facing each other and having upper confronting edges with recesses having serrated bases. Each of the antenna elements consists of a plurality of telescoping sections so that they may be independently collapsed or extended to any desired length. The inner ends of the antenna elements project through corresponding openings formed in the assembled brackets -and are pin connected to the brackets to permit their 'Wthe tuning elements each of which likewise consists of a angular adjustment, the serrated confronting bases of the bracket wall recesses maintaining the antenna elements in selected angular positions. Also carried by the brackets in upright, parallel, closely spaced positions are plurality 'of telescoping sections to permit their collapse or extension to any desired length. The tuning elements are openended, the open ends being engaged by a common insulated .finger pieceto'facilitate the adjustment dofthe tuning elements ,to similar positions. a A .rotary along line 4-4 in peripheral walls provided along their .3 selector'switch is housed the cavity defined by the brackets and 'is "carried between the walls thereof, the shaft of the switch passing "through one of the brackets and terminating in a suitable knob. The switch includes a pair of two=fingered"rotary arms rotated in .uriison, and so connected tothe innerends of the tun ng elements and of the antenna elements'and to the' termini eta t-rans-' mission line or other "suitable terminals to permit :thelintel-connection between each 'of the antenna. elementsto a corresponding tuning element Land the coupling'offthe.

transmission line termini to the respective junctions as well as'ayariety of other combinations that will be hereinafterdescribed. i

Reference is now'made to the drawings .which'iillustrate -a preferred-embodiment of the present invention,

wherein the numeral generally designates a base or pedestal pre'ferablyformed of. metal and sufiicientl'yheavy to support the antenna in any desired position and farrangement. "T he 'base'10 is provided with laterally. spaced parallel ridges 11 and 12 and has formed .therein ajbottom well 13 and an upper'well 14. A passageway 16fis disposed between and separates the ridges 12. A pair .of cup-shaped bracket'members I7 and19are verticallyarranged'withtheiropen endsconfronting each other and are provided with horizontally projectingperipheral walls 20 whose respective ledges abut each other, the bottom o'f-the assembled brackets being flattened as at -21-..and resting upon the "base ltl'between the ridges -I1.and..12 and being tightly secured thereto by means of a suitable nutandboltfastener 22 passing through corresponding aligned openings formed in the'bracket assembly andin therbase .10. Furthermore, the bracket members Hand 19 'have confronting recesses 18 formed intheir upper perip'heralwalls extending from the'horizontal diameter of, the brackets to points short of the top thereof, the bases of the recesses'being suitably serrated.

The antenna elements are designated as 25 and. 2'6-.respectivelyandeach consists of 3 slidibly telescoping'sections 27,28 and 29 of conventional ,constructionihe section 29 being'rod shaped and terminating 'in-a plastic ball 30. The

sections

27 and 28 are tubular having .their outer ends inwardly 'swaged and their inner ends outwardly swaged whereas the section 29 has its inner end, outwardly swaged toprevent the separation of theaseveral sections. sections 2.7 projects into the bracket cavity .throu'ghthe respective slots .defined by the recesses.18:and sfflattened, as "at 32, and is provided with a -circular.aperture.which rotatably engages a-corresponding p in,'33 ,supportedrin aligned wells formed in oppositely disposed bosses or stubs 34 locatedupon confronting faces -of-the. bracket members Hand 19. A pair of helical compression springs 36 register with thepin33 andareentrappedsbetween the opposite faces of the antennaflattened v.end 32 andjthe confronting faces of: the stubs 34. .Itshouldbe noted that a pair of stubs 34 are ,providedforeachtof the antenna .elements 25 and .26 and arelocatedin-dia metrically opposedpositions and arehorizontally spaced. Thus, by means ofthe above construction,..the.antenna elementsi25 and 26 are independently adjustable to any desired length andarelikewise independently adjustable to any desired angular, position being maintainedatsuch position by being engaged by .the opposite serrated bases of .the recesses 18.

The tuning. elements,.designated as 40 and 41 respec- The inner end of each of the antenna-element ings formed in the brackets 17 and 19 and terminating in transversely projecting pins 43 which are engaged by elements 40 and 41-to correspondingly equal lengths.

Housed in the 'cavity formed in the bracket assembly is s a vrotary swit'ch consisting -0fa base-plate- 5-1, an intermediate contact carrying plate 52 and a detented index plate 53 the plates "51, 52 and S3 being'asseml'iled and supportedv in parallel laterally spaced position by a suitable pair of screws and nuts 54 the screws passing through eorresponding' openings formed in the plates 51, 52 and S3 and having registering therewith between the successive plates tubular spacing elements 56. The

- brecketmembers -17.and 19 have centrally disposedhubs 56.and 57 respectively, integrally formed-'thereon the switch-baseplateJSl being secured to the inneri faceof the hub 57 by means of a screw 58 passing through a corresponding opening.formed in the hub5'7 and engaging a tapped-opening formed in the switch baseiplate 5.1. removable cap 59 seals the-front opening in ;the

hub-57. -Mounted on the index plate 53 and projecting f onwardly-thereof isan'externally threaded bushing-"60 which-,massestthrough an opening in the hub 56-randds tightly secured thereto by means of a nut61fengaging the threadedwbushingfiil and adjusted into tight abutment with-the touter-vfacetofwthe hub 56. The contactgplate S2:carries=on opposite-:faceszthereof a lower set of five contacts AL Az, aAS,.-A4 and A5 respectively, and an 1 upper set:of regularlytspaced contacts; B1, :B2, B3, B4

and :B5-res pectively.' Thesuccessive contacts in caclnset areaseparatedbya'unit increment. A shaft 65fiextends through thebushing-60 projectingbeyondbothends thereof and carries :at its inner end, by means of suitable. in

t sulated discs, azpair'of switch'arms 66 and .G'Z'I'CSPECilVQ lY,

the-switch arm '66being .provided with a pair-cffingers 68 and 69 :separated by four increments rand fadapted to :be:-brought into selective registry with the lowerwsettof contacts :AIl'to A5 whereas the arm 67.is provided with fingers 70 and 7-1 likewise angularly. spaced four incre ments'aandiadapted i to be brought into registry withcorresponding :contaetsBl through B5. The switchwarrns 66:a:nd :67.;are.:rotatable .in unison. and are carried by thc shaft 65 .aontopposite sides o'fxthe contact plate 52, the relative :positions of the fingers -68 and'ti9 and"70-and 7llcbeingtsuch thatwhen'the finger- 69 registers-With the contact. Aldhe "finger 70 registers with the contact-B1 and-Lthe arms are rotatable so that the'fingers 69 and- 7b register :with successive contacts A1, A2,.A3, Adnnd-A'S and-B1 B2,'-'B3, =B4 and l35 respectively. Also carriedby the shaft 65- is .a disc "72 which is provided with sprung fingers which are brought into registry'with successive detents formed on' the index plate "53 in a conventional mannerso that the fingers 69 and '70 are positioned in registry with successive contacts. It should be noted that Whenthe fingers 69 and 7(l'register with contacts AS and 'BSthejfingers 68 and 71 register with the contacts A1 :andiBl. .T he electrical connection of the tuning elements, the switches and the transmission line terminals areillus'trated in' Figure 6 of the drawing. The transmission'lineterminals'73..and 74 are connected to the switch arms- 66 .and-67 respectively by meansof suitable brushes. .Thecontacts A1 and A2 are commonly connected to -the antenna element 26 Whereas thecontactelemeuts B1 and B3 :are connectedto the antenna elements 25. Eurther-more, the contact elements A3, A4 and AS-are connected :tothe tuning--element- 60 and the 'contact elements B2,.B4 HIldnBS :are connected .tozthetuningaelernent 41. Thewvarious electrical connections mays'be-anade with insulation acovered twiresin itheconventional-manner. l tre shaft 65acarries a :suitable knob 76 provided with a pointer 77 which cooperates with the indicia 78 carried on the face of the front bracket member 17. Thus when the switch 50 is in the first position as indicated in Figure 6 of the drawings wherein the fingers 69 and 7:; register with the contacts A1 and B1 respectively, the transmission line termini 73 and 7 2- are each connected only to the corresponding antenna elements 25 and By advancing the switch to its second position the finger 69 registers with the contact A2 and the finger 70 registers with the contact B2 thereby connecting the transmission line conductors to the antenna element and the tuning element 41 respectively. As the switch is advanced to the third position wherein the finger 69 registers with the contact A3 and the finger 70 registers with the contact B3, the transmission line termini are connected to the tuning element 40 and to the antenna element 25 respectively. In the switchs fourth position the finger 69 registers with the contact A4 and the finger '70 registers with the contact B4 thereby connecting the transmission line termini 73 and 74 to the tuning elements and respectively. In order to connect the transmission line to both tuning elements and to both antenna elements the switch is rotated to its fifth position wherein the

fingers

68 and 69 register with the contacts A1 and A5 and the fingers 7t) and '71 register with the contacts B3. and B5 so that the transmission line terminal '73 is coupled to the tuning element and the antenna element 26 which are electrically connected at their inner ends and the terminal 74 is connected to the turning element 41 and the antenna element 25 which are llliwise connected at their inner ends. In the sixth position of the switch the transmission line is completely disconnected from the antenna elements and the tuning elements.

Considering now the operation of the improved antenna, it is connected by way of a conventional 300 ohm transmission line 80 to the input terminals of a television receiver. The switch is set at its fifth position and the

tuning elements

25 and 26 are then spread and the lengths thereof adjusted until maximum signal is received as indicated by the image on the picture tube. The antenna is then oriented and located in a position whereby minimum ghosts are observed and maximum signal obtained. Thereafter the height of the

tuning elements

40 and 41 are adjusted to effect an optimum impedance match between the antenna and the transmission line 80 as determinable by the fidelity and definition of the received picture and by the absence of ghosts. In the majority of cases this procedure will result in the reception of an optimum picture. However, in the event that reception is still unsatisfactory, the switch 5'5 may be adjusted to any of its other positions and the antenna and tuning elements manipulated until optimum reception is achieved. It should be noted that in the commercial embodiment of the present inven tion the

tuning elements

40 and 41 are continuously adjustable in length from approximately 4 /2 inches to approximately 12 /2 inches whereas each of the antenna elements are adjustable in length from approximately 17 /2 inches to approximately 43 inches, greater lengths being somewhat awkward.

While there has been illustrated and described a preferred embodiment of the present invention it is apparent that numerous alterations and omissions may be,

made without departing from the spirit thereof.

What is claimed is:

1. An improved antenna comprising a base portion, a pair of separated antenna elements disposed at an angle to the vertical and carried by said base member, a pair of parallel open ended tuning elements of adjustable length, each of said tuning elements being coupled to a corresponding antenna element and a transmission line having a pair of conductors, each of said conductors being connected to a respective set of antenna element and tuning element.

2. An improved antenna comprising a base member, a pair of laterally spaced elongated antenna elements pivotally connected to said base member adjacent their inner ends to permit the relative angular adjustment thereof, each or" said antenna elements including a plurality of mutually slidable telescoping members, an open ended pair of parallel elongated tuning elements carried by said base member, each of said tuning elements including a plurality of mutually slidable telescoping members, a pair of conductors and switching means connected to said pair of conductors and said tuning elements and said antenna elements whereby to permit selective coupling of said conductors to said tuning elements and antenna elements, solely to said tuning elements, and to a single tuning element and a single antenna element respectively.

References Cited in the file of this patent UNITED STATES PATENTS