US3005982A - Indoor antenna for television reception - Google Patents

Description

Oct. 24, 1961 P. A. BERNFELD 3,

INDOOR ANTENNA FOR TELEVISION RECEPTION Filed June 28, 1960 2 Sheets-Sheet 1 INVENTOR. PHILIP ABRAHAM BERNFELD gmw A TTOP/VFY Oct. 24, 1961 P. A. BERNFELD INDOOR ANTENNA FOR TELEVISION RECEPTION 2 Sheets-Sheet 2 Fil ed June 28, 1960 INVENITOR. PHILIP ABRA HAM BERNFELD" LOOP ARRAY SELECTOR POSITION P2 P3 P4 P5 ATTOPA/T) 3,005,982 INDOOR ANTENNA FOR TELEVESTON RECEPTION Philip Abraham Bernfeld, 15314 73rd Ave.,

Flushing, N .Y. Filed June 28, 1960, Ser. No. 39,280 Claims. (Cl. 343-724) with a plurality of vertically disposed loops mounted on a base and interconnected via adjustable switch means in any of a plurality of predetermined arrays.

A further object is to provide a novel assembly of Vertical loops and horizontal dipoles in an indoor antenna.

Another object is to provide an assembly of loops and dipoles in an indoor antenna in which the loops and dipoles can be serially connected or individually connected to an antenna lead-in transmission line while unconnected loops and dipoles serve as reflectors to shield the signal receiving members against spurious signals.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

FIG. 1 is a top plan view of an antenna assembly em bodying the invention.

FIG. 2 is a front elevational view of the antenna assembly.

FIG. 3 is a vertical cross-sectional view taken on line 33 of FIG. 1.

FIG. 4 is a schematic diagram of the antenna assembly.

FIG. 5 is a chart identifying and listing the several arrays of loops in the different positions of the selector switch.

FIGS. 6 and 7 are cross sections of rod and tubing useful in forming the antenna.

Referring to FIGS. l-3, there is shown a rectangular base 10 providing a platform 12 on which is mounted a plurality of generally circularly curved conductive, tubular loops V1-V4 open at the bottom. The loops have a vertical diametral length substantially equal to one quarter of the wavelength of the center frequency of the broadcast band to which the antenna is responsive. The ends of the several loops are joined by horizontally disposed conductive, tubular links III-H3 which are center tapped at T1-T3; see FIGS. 3 and 4.

The taps T1-T3 pass through openings in the platform 12 into the cavity defined by platform 12 and walls 15-18 of the base. Loops V1 and V4 have ends connected to horizontal unipoles HD4A and HD4B. The ends of these unipoles are joined to a resistor 20. These ends terminate in taps T4A and T4B;

On front wall 15 of the base is a selector switch 22 controlled by a knob 24 marked with an index mark 25 to indicate its switch position. Eight switch positions P1-P8 are provided but more or less switch positions may be employed if desired.

The switch 22 includes an insulated disk 26 on which are lugs 28 to which are connected Wires 30. The wires are preferably conductors shielded by braided wire or center conductors of coaxial cables. The lugs are arranged in eight pairs and are connected to an inner circular array of spaced fixed contacts C1-C8 and to an outer circular array of spaced fixed contacts C1C8 at switch positions P1P8, respectively; see FIG. 4. The knob 24 is mounted on an insulated shaft 23 which carries two spaced conductive rings 29, 31. Ring 29 has a radial arm 32 which makes contact with the inner contacts C1-C8 in turn at the several switch positions. Arm 34 is carried radially by ring 31 and is spaced angularly from arm 32 a fixed distance to that arm 34 contacting one of the outer contacts C1'C8 of a pair, while arm 32 is contacting the inner contact C1-C8 of the same pair. Transmission line 36 has conductors 38, 40 terminating in wiper contacts 39, 41 for making contact with rings 31 and 29, respectively, in all positions thereof.

FIG. 5 lists in chart form the array of loops to which line conductors 38, 49 are connected at each of the positions P1-P8 of the selector switch. At positions P1, P2, P4 and P6, individual loops V1, V2, V3 and V4 are connected to the external transmission line. At positions P2, P5 and P8, two loops V1, V2; V2, V3; and V1, V4 are serially connected. At switch position P7, three loops V1, V2 and V3 are serially connected.

Thus, by setting the switch 22 to each position in turn, it is possible to orient the antenna for optimum reception of signals emitted by stations broadcasting from any of several directions.

When any one loop or group of loops are connected to the line 36, the remaining unconnected loops serve as active reflectors to stop spurious signal reflections approaching from directions removed from the direction of approach of the desired signals.

The antenna assembly is simple to operate, requiring only a single control knob. The user will tune the antenna by rotating the knob until optimum reception is noted at the receiver (not shown) connected to the transmission line.

The horizontal links in the several arrays increase the gain of the antenna by picking up components of signals arriving from directions other than horizontal. They therefore constitute in effect horizontal dipoles in series with vertical loops. Since the loops are primarily inductive in nature while the horizontal links are primarily capacitative, they may constitute tuned resonant circuits which serve to resonate and intensity the amplitudes of the received signals.

The several links and loops may be formed from a single length of aluminum or other metal tubing bent to the form shown in the drawings. The tubing may be coated with cooper, cadmium, silver, or other highly conductive metal to improve reception by reducing high frequency energy losses. As an alternative the loop may be formed of low-loss plastic rod 50 or tubing 52 coated with a highly conductive metal coating 51 or 53 as indicated in FIGS. 6 and 7, respectively.

While I have illustrated and described the preferred embodiment of my invention, it is to be understood that I do not limit myself to the precise construction herein disclosed and that various changes and modifications may be made within the scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent 1. An antenna for reception of high frequency broadcast signals, comprising a base, a plurality of conductive loops disposed in vertical planes at right angles to each other on said base, horizontal links connecting ends of the loops, switch means having a plurality of switch positions, said horizontal links having taps connected to said switch means at the several positions thereof, and a transmission line connected to rotatable contacts of said switch means, whereby selected ones of said loops and links are connected to said line at each position of the switch while the other loops and links serve as reflectors shielding the selected loops and links from spurious radiated signals.

2. An antenna for reception of high frequency broadcast signals, comprising a base including a raised platform and side walls defining a cavity therewith, a rod having an external electrically conductive surface, said rod being formed to define four loops and four dipole links, said loops being disposed in vertical planes at right angles to each other on said platform, said links being disposed horizontally and having taps extending through said platform into said cavity, multiple position switch means mounted on one of said walls and having spaced contacts connected to said taps, said switch means having rotatable contacts, and a transmission line having wipers connected to said rotatable contacts whereby selected ones of said loops and links are connected to said transmission line at each of the positions of said switch means.

3. An antenna for reception of high frequency broadcast signals, comprising a base including a raised platform and side walls defining a cavity therewith, a rod having an external electrically conductive surface, said rod being formed to define four loops and four dipole links, said loops being disposed in vertical planes at right angles to each other on said platform, said links being disposed horizontally and having taps extending through said platform into said cavity, multiple position switch means mounted on one of said walls and having spaced contacts connected to said taps, said switch means having rotatable contacts, and a transmission line having wipers connected to said rotatable contacts whereby selected ones of said loops and links are connected to said transmission line at each of the positions of said switch means, said rod being formed of low-loss material coated with highly conductive metal.

4. An antenna for reception of high frequency broadcast signals, comprising a base including a raised platform and side walls defining a cavity therewith, a rod having an external electrically conductive surface, said rod being formed to define four loops and four dipole links, said loops being disposed in vertical planes at right angles to each other on said platform, said links being disposed horizontally and having taps extending through said platform into said cavity, multiple position switch means mounted on one of said walls and having spaced contacts connected to said taps, said switch means having rotatable contacts, and a transmission line having Wipers connected to said rotatable contacts whereby selected ones of said loops and links are connected to said transmission line at each of the positions of said switch means, said rod being a plastic tube coated with highly conductive metal.

5. An antenna for reception of high frequency broadcast signals, comprising a base including a raised platform and side walls defining a cavity therewith, a rod having an external electrically conductive surface, said rod being formed to define four loops and four dipole links, said loops being disposed in vertical planes at right angles to each other on said platform, said links being disposed horizontally and having taps extending through said platform into said cavity, multiple position switch means mounted on one of said walls and having spaced contacts connected to said taps, said switch means having rotatable contacts, and a transmission line having wipers connected to said rotatable contacts whereby selected ones of said loops and links are connected to said transmission line at each of the positions of said switch means, said rod being a metal tube.

6. An antenna assembly comprising an array of conductive loops disposed in vertical planes at angles to each other, successive loops being connected by horizontal curved links center-tapped to define dipoles, two of said loops terminating in taps connected by a resistor, a multiple position switch having fixed contacts connected to taps of the links, rotatable contacts disposed to contact the fixed contacts at each position of the switch, and a transmission line having terminals making wiping contact with the rotatable contacts for selectively connecting individual ones of said loops to the transmission line at certain positions of the switch and for selectively connecting groups of serially connected loops and links in others of the switch positions.

7. An antenna assembly comprising an array of conductive loops disposed in vertical planes at angles to each other, successive loops being connected by horizontal curved links center-tapped to define dipoles, two of said loops terminating in taps connected by a resistor, a multiple position switch having fixed contacts connected to taps of the links, rotatable contacts disposed to contact the fixed contacts at each position of the switch, and a transmission line having terminals making wiping contact with the rotatable contacts for selectively connecting individual ones of said loops to the transmission line at certain positions of the switch and for selectively connecting groups of serially connected loops and links in others of the switch positions, there being four of said loops and four of said dipoles in planes in said array at right angles to each other.

8. An antenna assembly comprising an array of conductive loops disposed in vertical planes at angles to each other, successive loops being connected by horizontal curved links center-tapped to define dipoles, two of said loops terminating in taps connected by a resistor, a multiple position switch having fixed contacts connected to taps or the links, rotatable contacts disposed to contact the fixed contacts at each position of the switch, and a transmission line having terminals making wiping contact with the rotatable contacts for selectively connecting individual ones of said loops to the transmission line at certain positions of the switch and for selectively connecting groups of serially connected loops and links in others of the switch positions, there being four of said loops and four of said dipoles in planes in said array at right angles to each other, said loops and links being formed by a single piece of bent conductive material.

9. An antenna assembly comprising an array of conduc- *tive loops disposed in vertical planes at angles to each other, successive loops being connected by horizontal curved links center-tapped to define dipoles, two of said loops terminating in taps connected by a resistor, a multiple position switch having fixed contacts connected to taps of the links, rotatable contacts disposed to contact the fixed contacts at each position of the switch, and a transmission line having terminals making wiping contact with the rotatable contacts for selectively connecting individual ones of said loops to the transmission line at certain positions of the switch and for selectively connecting groups of serially connected loops and links in others of the switch positions, said loops and links being formed by a single piece of bent and shaped plastic rod coated with metal.

10. An antenna assembly comprising an array of conductive loops disposed in vertical planes at angles to each other, successive loops being connected by horizontal curved links center-tapped to define dipoles, two of said loops terminating in taps connected by a resistor, a multiple position switch having fixed contacts connected to taps of the links, rotatable contacts disposed to contact the fixed contacts at each position of the switch, and a transmission line having terminals making wiping contact with the rotatable contacts for selectively connecting individual ones of said loops to the transmission line at certain positions of the switch and for selectively connecting groups of serially connected loops and links in others of the switch positions, said array being formed by a single piece of metal tubing bent and shaped to form said loops and links.

No references cited.

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