US3392399A

US3392399A - Combined vhf-uhf television antenna with serpentine director

Info

Publication number: US3392399A
Application number: US488130A
Authority: US
Inventors: John R Winegard
Original assignee: Winegard Co
Current assignee: Winegard Co
Priority date: 1965-09-17
Filing date: 1965-09-17
Publication date: 1968-07-09
Anticipated expiration: 1985-07-09

Description

July 9, 1968 J. R. WINEGARD 3 39 ,39

COMBINED VHFUHF TELEVISION ANTENNA WITH SERPENTINE DIRECTOR Filed Sept. 17, 1965 5 Sheets-Sheet 1 l I Inventor fig- 39 8 Jo hn Rflllinega rd fl-ktomegs y 9, 1968 R. WINEGARD 3,392,399

COMBINED VHF-UHF TELEVISION ANTENNA WITH SERPENTINE DIRECTOR Filed Sept. 17, 1965 5 Sheets-Sheet 2 Infienkor' John. R. (Ninegard July 9, 1968 J R. WINEGARD 3, 9 ,3

COMBINED VHF-UHF TELEVISION ANTENNA WITH SERPENTINE DIRECTOR Filed Sept. 17, 1965 5 Sheets-Sheet 5 Invenl'or m I John R.Wines0rd United States Patent Oflice 3,392,399 Patented July 9, 1968 Iowa Filed Sept. 17, 1965, Ser. No. 488,130 4 Claims. (Cl. 343815) This invention relates in general to antennas and director elements therefor and more particularly to an improved antenna and director element operable in one frequency range (such as the high VHF television frequency band) without a substantial degradation of performance at another frequency range (such as the UHF- television frequency band).

Effective television antenna operation is facilitated by the use of one or more director elements located in front of the driven elements of the antenna system. 'Directors are, however, very frequency sensitive. An element that serves as a director in one operating frequency range, e.g., television channels 7-13, will not serve as an effective director in other frequency ranges, such as the range covering channels 14 to 83. Moreover, a director for channels 7 to 13 is so long at the wave lengths of channels 14 to 83 that it will tend to shield or otherwise degrade the UHF driven elements behind or adjacent thereto.

The present invention rests on the rather surprising discovery that with crinkled or serpentine" convolutions formed in the inboard portions of the respective arms of a dipole director, it, the director, may be made of a length for effective operation at a relatively low frequency range (e.g., television channels 7-13) while at higher frequencies (e.g., covering channels 14 to 83) acting as if in the form of a plurality of short, electrically isolated, elements. The operation in this respect is all the more surprising because the serpentine portions .of the dipole director provide an isolation effect which is not unduly frequency sensitive and therefore is free from the frequency responsive effect ordinarily associated with resonant elements in an antenna.

In accordance with the preferred embodiment of the present invention, as applied to a complete television antenna structure, an antenna is provided having a VHF system and a UHF system separated along the axis .of an antenna boom and inter-coupled to a common transmission line wherein each system operates substantially independently of the other. The VHF system includes a plurality of half wave dipole driven elements, each cut to a particular television channel in the low VHF band, that is, channels 2 to 6, inclusive. For high band operation, unitary parasitic elements may be placed parallel to and in impedance coupling relation to associated dipole driven elements. In its preferred form there are three such parasitic elements. The front-most unitary element acts to load the front-most dipole element to approximately the second harmonic and render the same effective as the main pickup element. The second unitary element is operative to control the impedance of the antenna at the high end of the high VHF band while the third unitary element is effective to render the third dipole driven element operative as a erative to provide director action in a given frequency range but does not load or shield or otherwise affect the performance of the driven or other elements operative at a higher frequency range than said given range.

It is another object of the present invention to provide a director element of the above type capable of achieving director action for television channels in the high VHF band while at the same time does not degrade the performance or otherwise affect the operation .of adjoining UHF television driven elements. 1

Another object of the present invention is to provide an improved all-channel television antenna capable of providing relatively high-gain reception in boththe VHF and UHF television bands through the use of a director element with crinkled or serpentine convolutions over a portion of its length.

Still another object of the present invention is to provide an antenna for television reception which exhibits relatively uniform gain over the entire television frequency spectrum characterized by a simple, light-weight, compact and low-wind resistance yagi construction, short boom length and other features providing a highly practical structure for television use.

It is a further object of the present invention to provide an improved all-channel television antenna and director therefor utilizing features of construction, combination and arrangement wherein a simple, compact, effective and readily manufactured antenna structure is provided, to the end that a product of maximum commercial usefulness is achieved.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, itself, however, together with further objects and advantages thereof, will best be understood by reference to the following description taken in conjunction with the drawings, in which:

FIGURE 1 is a view in perspective of a television antenna constructed in accordance with the present invention;

FIGURE 2 is an enlarged fragmentary view from the front taken generally along'lines 22 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary view from the bottom of the full-wave dipole director;

FIGURE 4 is a schematic representation of the antenna of FIGURE 1';

FIGURE 5 is an enlarged fragmentary view from the side showing the interconnection between the VHF and the UHF antenna systems;

FIGURE 6 is an enlarged fragmentary view from the bottom showing in detail the transposed phasing lines interconnecting the pairs of dipole driven elements;

FIGURE 7 is an enlarged fragmentary view from the side showing the phasing lines interconnecting the dipole driven elements of the VHF system;

FIGURE 8 is an enlarged fragmentary cross sectional view of a mounting detail of the saddle bracket supporting the VHF dipole driven elements taken generally along lines 88 of FIGURE 7;

FIGURE 9 is a fragmentary view in perspective showing a mounting detail for a saddle bracket supporting the UHF dipole driven elements taken generally along lines 99 of FIGURE 5; and

FIGURE 10 is a fragmentary view from the bottom of a director unit operable in both low and high VHF bands.

Referring now to FIGURE 1, an all-channel television antenna 10 is shown constructed in accordance with the present invention. The antenna- 10 includes a VHF system indicated generally at 11 and a UHF system indicated generally at 12 (FIGURES 1 and 4). The antenna structure is supported on a vertical support mast M, to which a horizontal cross-arm or boom B is afiixed. The boom B may be supported on the mast M by any suitable means such as the -U-bolt bracket assembly U (FIG- URES 6 and 7).

The VHF system 11 includes a series of driven

elements

20, 22, 24, 26, 28, 30 and 32. These are in the form of simple dipoles positioned in an aligned, substantially coplanar, relationship along the boom B. Each of the dipoles is supported on the boom by a straddle bracket formed of suitableinsulating material and indicated at 21, 23, 25, 27, 29, 31 and 33. Each of the brackets includes a generally circular area which seats on the boom B, as shown in FIGURE 8 for the bracket 21. It is understood that the

brackets

23, 25, 27, 29, 31 and 33 have the same construction asbracket 21 and support the

respective dipole elements

22, 24, 26, 28, 30 and 32 in the same manner. The bracket 21 further includes laterally extending wing portions 21a and 21b. The bracket 21 is aflixed to the boom B by a rivet 21;- passing through suitable clearance holes provided in the bracket and boom as shown.

Each of the dipoles 20 to 32 includes a pair of arms, being indicated at 20a and 20b, 22a and 22b, 24a and 24b, 26a and 26b, 28a and 28b, 30a and 30b, and 32a and 32b, FIGURES 4 and 6. The respective dipole arms preferably rest on top of the associated support bracket, as.seen in FIGURE 8, and are aflixed thereto by an associated rivet 20;- passing through the respective dipole arms, near the inboard ends and through the ends of the support bracket. The rivets 20r attaching the

dipole arms

20a and 20b to the associated support brackets further serve as effective connection terminals for receiving the interconnecting phasing line conductors shown at 18-18 in FIGURES 1 4, 6 and 7 The respective connections are made by wrapping a portion of the conductors 18-18 around each of the rivets at least one turn so as to ensure that a positive electrical contact as well as a secure mechanical connection is obtained. The transmission line conductors 18-18 are crossed or transposed between each of the

dipole elements

20, 22, 24, 26, 28, 30 and 32. The transmission line 18 has a construction wherein a series of serpentine or sinusoidal convolutions are formed in the plane parallel to the plane of the dipole elements, best seen in FIGURE 6, so that the physical spacing between the respective dipole elements are substantially less than the actual length of the interconnecting phasing lines 18-18 as will be subsequently described.

The VHF system 11 also includes a full-wave dipole director element 38 positioned in front of the foremost driven dipole element 20, FIGURES 2 and 3, and serving as a director for the high VHF band, or television channels 7 to 13, inclusive. A number of

unitary elements

40, 42 and 44 are placed in close proximity to the driven dipole elements to effect eflicient operation of antenna structure 10 within the high VHF band, or television channels 7 to 13, inclusive. The unitary element 40 is positioned in front of the dipole driven element 20 a short distance, i.e., approximately 2% inches, while the

unitary elements

42 and 44 are placed in substantial vertical alignment with the respective .dipole driven

elements

22 and 24 by being properly located on the underside of the boom B, best seen in FIGURE 7.

The driven dipole elements 20 to 32 are cut to particular frequencies within the low VHF. band. The dipole element 32 has a half-wave length generally corresponding to channel 2; dipole element 30 has a half-wave length generally correspondingtochannel 3; dipole element 28 corresponds generally to channel and dipole element 24 corresponds generally to channel 6. For VHF high band operation, that is, channels 7 to 13, the

unitary elements

40, 42 and 44 in conjunction with the driven

dipole elements

20, 22 and-24 are operative to provide for efficient reception of television signals in this range. Y

The UHF system 12 is positioned in front of the VHF system 11 a predetermined distance and in a substantially coplanar aligned relation thereto. The UHF system 12 consists of a series of dipole driven

elements

50, 52 and 54 and a reflector 60 positioned to the rear and a director assembly 5658 positioned to the front of the driven elements. The UHF system includes the dipole driven

elements

50, 52, and 54 aligned in a coplanar relation on the boom B, and supported thereon by associated straddled brackets, indicated respectively at 51, 53 and 55. FIGURE 9 shows in detail the mounting arrangement for bracket 51 in supporting the dipole element 50, and in turn being supported on the boom B. It is understood that brackets 53 and have the same construction and support the

dipole elements

52 and 54, respectively, in the same manner. The bracket 51 is formed with a pair of outwardly extending arms 51a and 51b and a generally fiat surface 51c at the center. A rectangular groove or slot 51d is included to ride on the boom B in the manner shown. The bracket 51 is secured to the boom by a rivet 51;- extending thru the surface 510 and the boom B. The vertical sides of the slot 51d bear against the boom and hold the bracket from rotating thereon. The dipole element 50 includes

arm members

50a and 50b supported on the bracket 51 by suitable means, such as rivets 50r, securing the inboard ends of the

arms

50a and 50b to an end portion on the bracket 51. The rivets 50r extend thru a vertical sleeve 51s to terminate in a fiat end portion at each end of the rivets. A washer 51w is seated under the bottom end of each of the rivets 51r, a portion of which overlaps the transmission line conductors 19-19 and bears against the same under the action of the rivets 512' to hold the lines in place and ensure positive electrical contact thereto. The transmission line conductors 19-19, the bracket 51, and the associated

dipole arms

50a and 50b are held in a sandwiched relation by the rivets 5112 The transmission line conductors 19-19 extend forward from the dipole driven element 54 on the underside of the boom B (viewing FIGURE 5) to interconnect the

dipole elements

52 and 50 and then rearwardly from the element 50 on the top side to connect to the dipole driven element 20 of the VHF system 11.

A UHF director assembly is positioned in front of the driven

elements

50, 52 and 54 and includes a unitary director element 56 and a dipole director element 58. The unitary director 56 is positioned forward of the foremost dipole driven element 50 and the dipole director 58 is interposed between the unitary director 56 and the dipole driven element 50. The dipole director 58 is supported on the boom B by an insulating saddle bracket 59 similar to the

brackets

51, 53 and 55. A UHF reflector 60 is positioned rearwardly of the dipole driven element 54. The

UHF directors

56 and 58 provide their principal action at the high end of the UHF band while the reflector 60 provides reflector action principally at frequencies at the low end of the UHF band.

As previously mentioned, the UHF and

VHF systems

11 and 12 are interconnected by a length of the open transmission line 19-19. As seen in FIGURE 5, the length of the transmission line connecting the UHF dipole element '50 to the VHF dipole element 20 is relatively long. It has been found that, if the length of the transmission line is within a predetermined range, the VHF and UHF systems will operate substantially independently of one another without the need of tuning stubs or the like. In a construction found satisfactory the length of the interconnecting transmission line 19-19 between the UHF dipole element 50 and the VHF dipole element 20 approximated 19 inches.

The antenna 10 is preferably formed of aluminum tubing or rod. The phasing lines and the various dipole and unitary elements can be stamped from a metal plate in one or more sections or cast from metal plastic that has been suitably plated with a metallic conductor. In one specific construction found satisfactory, the arms of the directors, dipole and unitary elements were formed VHF SYSTEM Element Span (inch) Arm Length (inch) Dipole 32 110 Dipole 30 96 Dipole 28 90 Dipole 26 78 Dipole 24.-.. 66 Dipole 22 54 Dipole 20 48 Unitary director 44- 27. 5 Unitary director 42. 26.6 Unitary director 40 27 The dipole director 38 has a total span of 35 inches and an actual physical length of 46 inches (actual arm length 21.5 inches).

Distances along the boom B between the respective elements of the antenna are as follows:

Between

elements Inches

32 and 30 5.75 30 and 28 5.75 28 and 26 5.75 26 and 24 5.75 24 and 22 5 .75 22 and 5.75 20 and 40 2.5 40 and 38 11.75

Elements

42 and 44 are vertically aligned with the dipole driven

elements

22 and 24, respectively.

UHF SYSTEM Element Span (inch) Arm Length (inch) Unitary reflector 60 26 Dipole 54 17.5 7. Dipole 52 14. 5 5. 75 Dipole 50 11.75 4. 75 Dipole director 58 10 4. 0 Unitary director 56 5. 25

Distances along the boom B between the respective elements of the antenna 10 are as follows:

Between

elements Inches

60 and 54 4 54 and 52 3.75 52 and 50 3.75 50 and 58 2.25 58 and 56 3.25

PRACTICAL OPERATION In the practical operation of the antenna 10 for the low VHF band, that is, television channels 2 to 6, the dipole driven elements 20 to 32 become progressively half-wave resonant elements. For channel 2, for example, the dipole driven element 32 is approximately onehalf wave in length and provides eflicient reception of signals on that frequency. The shorter elements, that is, VHF dipole driven elements to 20, inclusive, either provide limited director action or are substantially ineflective. For channel 3, the dipole driven element 30 is approximately one-half wave in length at that frequency and provides eflicient reception therefor. In this instance, dipole element 32, being resonant at a lower frequency, provides a degree of reflector action while the shorter dipole elements 28 to 20, inclusive, are either inactive or provide some director action. For channel 4 operation, dipole driven element 28 is approximately one-half wave in length to provide eflicient reception of signals at that frequency while the

dipole elements

30 and 32 provide some reflector action and the dipole elements 26 to 20, inclusive, provide some director action. For channel 5, dipole driven element 26 is approximately one-half wave in length to provide eflicient reception of signals at that frequency while dipole elements 28 to 32, inclusive, provide some reflection action and dipole elements 24 to 20, inclusive, provide some director action. For channel 6 operation, the dipole driven element 24 is approximately one-half wave in length to provide for efficient reception of signals at that frequency while the dipole elements 26 to 32, inclusive, are operative to give some reflector action and the dipole driven

elements

22 and 20 provide some degree of direction action.

In the foregoing operation in the low VHF band, the respective dipole driven elements do not each become active or inactive at any one frequency. Moreover, for television reception, the respective channels are 6 megacycles in width. For these reasons, the actual operation of the antenna as a unit must be considered and not that of any one element divorced from the other elements. It is believed that the combined action also results from the relatively close spacings between the successive dipole elements, that is, spacings which are close in relation to the wave lengths of the VHF band frequency. Such spacings are on the order of 0.1 wave length with reference to the high end of the high VHF band, or approxirnately 200 megacycles. These spacings are seen to be substantially less than the actual physical lengths of the transmission phasing line conductors 18-18 interconnecting the dipole elements 20 to 32, inclusive. It is believed that the relatively close spacing of the VHF dipole elements 20- to 32 present a more favorable radiation capture capability for the antenna 10 as a whole while maintaining relatively broad band response and favorable gain and directivity characteristics by virtue of optimum lengths of the interconnecting phasing lines 18-48. The actual length of the phasing lines 1818 between the VHF dipole elements is approximately three times the spacing between dipoles.

In the high VHF band operation, 174 to 216 megacycles, covering channels 7 to 13, inclusive, the principally active elements are the dipole driven

elements

20, 22 and 24. The unitary element 40 is electrically coupled to the front VHF dipole driven element 20 so as to render the same effective as the main pickup element in the high VHF band. The element 40 loads the dipole element 20 to approximately the second harmonic of its natural half-wave resonant frequency. At the low end of the VHF high band, that is, television channels 7, 8 and possibly 9, the unitary element 44 is coupled to the dipole driven element 24 in a manner effective to make the latter provide a reflector action to increase the gain of the antenna. The unitary element 42 is coupled to the dipole driven element 22 in a manner effective to control the impedance of the antennna structure 10 at the high end of the high VHF band, or approximately 200 megacycles. As the frequency increases toward that of channels 10 to 13, the action of the elements change in that the operation is more and more influenced by the

unitary elements

40, 42 and 44. Unitary element 40 is cut to provide maximum director action at about channel 13 While

unitary elements

42 and 44 reflect their impedance into the associated

dipole elements

22 and 24, respectively, to provide a more favorable impedance match of the feed line L. Again, it will be noted that the dipole driven elements effective in this frequency range, namely

elements

20, 22 and 24, are spaced at physical distances approximating 0.1 wavelength at channel 13 while being connected electrically by transmission line conductors of approximately three times this distance. It has been found that the coaction of the dipole driven elements with the transmission line and the various unitary elements provides a relatively uniform gain and good impedance match throughout the VHF band covering channels 2 to 13, in elusive.

For UHF operation, 470 to 890 megacycles, covering television channels 14 to 83, inclusive, the active elements are the dipole driven

elements

50, 52 and 54, which are cut to particular frequencies within this range. As previously described, unitary element 60 provides reflector action while the unitary member 56 and the dipole member 58 provide director action, thereby contributing to the gain of the antenna operating in the UHF band. With the three driven dipoles, it has been found that a reasonably good impedance match is achieved with respect to the 300 ohm twin-lead feed line L.

With the antenna constructed according to the foregoing dimensions and physical spacings, a relatively efficient operation is achieved over the entire frequency spectrum. Gain of approximately 4 db is obtained from the VHF low band or 54-88 megacycles, a gain of approximately 6 db is obtained for the VHF gain high band or 174-216 megacycles while a gain of approximately 6 db is obtained for the UHF band, or 470-890 megacycles. The impedance presented by the antennna 10 remains relatively uniform over the entier television frequency spectrum and presents a reasonably close match to the 300 ohm twin-lead L, and in turn, to the antenna input terminals of an associated television receiver.

It is to be emphasized that the antenna of the present invention is characterized by physical spacings between the respective VHF dipole driven elements 20 to 32, inclusive, which are substantially less than the physical lengths of the transmission line conductors interconnecting them. Spacings of approximately 5.75 inches between the dipole elements have been found effective while the actual length of the interconnecting conductor is on the order of 19 inches.

This arrangement not only provides a uniquely compact arrangement, but also contributes to the overall efficiency of the antenna structure. It is not known with certainty just why this arrangement is so unusually effective but is believed to be a function of the coaction of the various elements with each other in a manner to increase the efficiency of radiation capture and the effect of a plurality of elements functioning as driven elements, reflectors or directors on any given television channel. In any event, the plurality of driven elements and the relatively close spacings described and claimed herein have been found to be effective and provide an all-channel antenna structure of unusually desirable characteristics with respect to gain, directivity, and impedance characteristics and overall size.

The relatively close spacings between the VHF dipole pairs in terms of the wave length at those frequencies, and the physical length of the interconnecting transmission line conductors, is accomplished in the manner best seen in FIGURE 6. The transmission lines 1 81 8 are formed with a series of waves on convolutions, indicated at 18a, for each segment interconnecting dipole pairs. The transmission lines 18-18 are preferably formed from relatively stiff wire of approximately #17 gauge, suitably tempered to hold its shape when so formed. The lines 1i8 18 are sufficiently light in weight to be readily suspendable between respective dipole pairs in a self-supporting relation, as shown in FIGURE 7. Further, the lines 18 18 are crossed or transposed between dipole pairs with an insulating material covering the portions of the lines, which would otherwise make contact with one another.

The antenna 10 is further characterized by a VHF dipole director element 38 having a series of crinkled or serpentine conformations 38w formed in the

respective dipole arms

38a and 38b at the inboard ends thereof, best seen in FIGURE 3. This construction has been found to aid considerably in minimizing the shielding or loading effect normally induced by such VHF director elements on adjacent UHF system elements.

Ordinarily, directors are relatively frequency sensitive such that a director element effective in one frequency range, e.g., television channels 7 to 13, will not provide efiicient director action in another frequency range, say, the UHF band covering channels 14 to 83. Furthermore, a director element to be effective in the range covering channels 7 to 13 will require a length which, without more, will ordinarily produce undesirable shielding or otherwise degrade the performance characteristics of any UHF driven elements that may be positioned adjacent or in otherwise close proximity thereto. For this reason, it has been a common practice in constructing all-channel television antennas to place the UHF system a substantial distance in front of the VHF antenna system.

In accordance with the present invention, however, the director element 38 is located in a position immediately adjacent (i.e., above) the UHF dipole element 52 and in front of the dipole element 54 and reflector element 60. The director element 38 has a span to provide fullwave director action at frequencies in the high VHF band covering television channels 7 to 13, inclusive. At frequencies in the UHF television band, 470 to 890 megacycles, the serpentine conformations 38w operate to provide a decoupling or isolation effect between the director element 38 and the UHF system elements 50-54. The precise nature of the decoupling action of the director element 38 is not fully understood but is thought to be the result of the serpentine conformations acting as if a plurality of short, electrically isolated, elements were present at frequencies in the UHF band rather than a single, continuous element. In any event, the result is a dipole director capable of operating efficiently in a selected frequency range which exhibits a progressively pronounced isolation effect as higher frequencies outside the selected range are approached with respect to any system elements immediately adjacent thereto. This permits the placing of UHF system elements in close proximity to the director element without undesirable shielding or loading of the same by the director unit. Further, a director unit is obtained which is not unduly frequency sensitive and therefore is free from the frequency responsive effect ordinarily associated with resonant elements in an antenna.

In one specific construction found satisfactory, the director element 38 was fabricated from solid aluminum rod having an CD. of inch. The span of the director 38 was approximately 35 inches and an arm length of approximately 16.5 inches. The outboard sections indicated at 38a and 38b of FIGURE 3 were approximately 7 inches in length with the axial length or span of the serpentine conformations SSW at the inboard ends approximately 7.5 inches. This represents a distance which extends outboard the terminal point of the longest UHF driven element, that being dipole element 54. The depth of the serpentine conformations, indicated by the arrow d, was approximately 2 inches with the distance between adjacent peaks, indicated by the arrow 1, approximately 3 inches.

It is to be understood, however, that the director unit 38 need not be limited to operation entirely within one VHF frequency band. A director element 138 is shown in FIGURE 10 which is similar to the director element 38, but which is capable of providing effective director action in both the low and high VHF bands. The director 138 includes a coupling unit 138c interconnecting the inboard ends of the respective arms 138a and 138b. The U-shaped coupling unit 1380 has an overall length which at frequencies in the low VHF band causes the unit to act essentially as a short circuit line with some inductive effect whereby the director 138 operates as a unitary element with a half-wave resonance at a frequency somewhat lower than its length would otherwise indicate. At higher frequencies, such as those in the high VHF band, the coupling unit 1380, in conjunction with stray capacitances induced by the surrounding metallic surfaces resonates at approximately the frequency at which the arms'l38u and 138/1 are half-wave in length. The lengths of the 9 arms 138a and 13811 are then chosen to provide director action in the high VHF band.

While only one specific embodiment of the invention is shown and described, it will, of course, be understood that many variations and modifications may be effected without departing from the true spirit and scope of the invention. The particular construction of the insulating supports, the connections between the dipole driven elements and the transmission line construction, the shape and form of the low VHF director unit, and other factors may be varied to suit the convenience of the maker or user of the antenna. The appended claims are intended to cover all such modifications and alternative constructions that fall within their true scope and spirit.

What is claimed is:

1. A television antenna structure operable in the VHF frequency range and in the UHF frequency range, comprising in combination:

a first antenna system for receiving television signals in the UHF range, said system including a plurality of elements in coplanar and aligned relation along a predetermined axis;

a second antenna system for receiving television signals in the VHF range, said antenna having at least one driven element located in back of and in substantially coplanar aligned relation with said first antenna system; and

a dipole director for said second antenna systems having a pair of arms and located in substantially coplanar aligned relation with said first antenna system, said dipole director being located in front of at least a portion of said first antenna system, said dipole director being of length to provide full wave director action at the high frequency portion of the VHF range and having serpentine conformations at the inboard end of each of the dipole arms whereby shielding or loading or other interference with performance characteristics of said first antenna system by said dipole director is effectively avoided.

2. A television antenna structure operable in the VHF frequency range and in the UHF frequency range, comprising in combination:

a dipole director for said second antenna system having a pair of arms and located in substantially coplanar aligned relation with said first antenna system, said dipole director being located in front of at least a portion of said first antenna system, said dipole director being of length to provide full wave director action at the high frequency portion of the VHF range and having serpentine conformations at the inboard end of each of the arms, said serpentine conformations being in the form of zig-zag convolutions in the plane of said first mentioned antenna system.

3. A television antenna structure operable in the VHF frequency range and in the UHF frequency range, comprising in combination:

a dipole director for said second antenna system having a pair of arms and located in substantially coplanar aligned relation with said first antenna system, said dipole director being located in front of at least a portion of said first antenna system, said dipole director being of length to provide full wave director action at the high frequency portion of the VHF range and having serpentine conformations at the inboard end of each of the dipole arms, said serpentine portions of each dipole arm containing at least half of the total length of conductor therein.

4. A television antenna structure operable in the VHF frequency range and in the UHF frequency range, comprising in combination:

a dipole director for said second antenna system having a pair of arms and located in substantially coplanar aligned relation with said first antenna system, said dipole director being located in front of at least a portion of said first antenna system, said dipole director being of length to provide full wave director action at the high frequency portion of the VHF range and having serpentine conformations in a plane parallel to the plane of said first antenna system at each of the inboard ends of the dipole arms, said serpentine conformations extending axially outwardly to a point beyond the outboard terminals of the longest UHF driven element in said first antenna system.

References Cited UNITED STATES PATENTS 2,992,430 7/1961 Winegard 343816 ELI LIEBERMAN, Primary Examiner.

Claims

1. A TELEVISION ANTENNA STRUCTURE OPERABLE IN THE VHF FREQUENCY RANGE AND IN THE UHF FREQUENCY RANGE, COMPRISING IN COMBINATION: A FIRST ANTENNA SYSTEM FOR RECEIVING TELEVISION SIGNALS IN THE UHF RANGE, SAID SYSTEM INCLUDING A PLURALITY OF ELEMENTS IN COPLANAR AND ALIGNED RELATION ALONG A PREDETERMINED AXIS; A SECOND ANTENNA SYSTEM FOR RECEIVING TELEVISION SIGNALS IN THE VHF RANGE, SAID ANTENNA HAVING AT LEAST ONE DRIVEN ELEMENT LOCATED IN BACK OF AND IN SUBSTANTIALLY COPLANAR ALIGNED RELATION WITH SAID FIRST ANTENNA SYSTEM; AND A DIPOLE DIRECTOR FOR SAID SECOND ANTENNA SYSTEMS HAVING A PAIR OF ARMS AND LOCATED IN SUBSTANTIALLY COPLANAR ALIGNED RELATION WITH SAID FIRST ANTENNA SYSTEM, SAID DIPOLE DIRECTOR BEING LOCATED IN FRONT OF AT LEAST A PORTION OF SAID FIRST ANTENNA SYSTEM, SAID DIPOLE DIRECTOR BEING OF LENGTH TO PROVIDE FULL WAVE DIRECTOR ACTION AT THE HIGH FREQUENCY PORTION OF THE VHF RANGE AND HAVING SERPENTINE CONFORMATIONS AT THE INBOARD END OF EACH OF THE DIPOLE ARMS WHEREBY SHIELDING OR LOADING OR OTHER INTERFERENCE WITH PERFORMANCE CHARACTERISTICS OF SAID FIRST ANTENNA SYSTEM BY SAID DIPOLE DIRECTOR IS EFFECTIVELY AVOIDED.