Radio antenna
First Claim
1. A radio transmitting antenna comprised of:
- an elongated conductive member having its ends in generally fixed spaced relationship and having an effective electrical length generally equal to λ
/2 at the desired frequency of operation;
means at one end of said conductive member for coupling said end of said conductive member to at least a transmitter tuned to said frequency;
and elongated generally rigid electrical insulating means extending beyond at least one end of said conductive member, the amount of extension being adjustable whereby said antenna may be elongated independently of the length of the conductive member and may be supported in any position by having the ends of said antenna engage opposed surfaces of a building.
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Accused Products
Abstract
A radio antenna which can be readily tuned to the exact frequency of operation, easily coupled to a coaxial feed-line with minimum standing wave ratio and/or which is normally vertical and can be used where horizontal space is at a premium, such as: indoors or on boats. The antenna has a center loading coil, the inductance of which is adjusted by means of a split coaxial sleeve axially moveable relative to the coil. The input impedance of the antenna is adjusted relative to the impedance of the feed-line by means of a coupling transformer, the transformation ratio of which is controlled by means of a coaxial split metal sleeve axially adjustable relative thereto. A coaxial cable wound into a coil around a ferrite core attenuates the high ratio frequency voltage on the end of the antenna to the feed-line. For indoor use, the antenna is housed in an extensible tubular housing which can be extended to engage the ceiling and floor of a room to hold the antenna in vertical position.
40 Citations
30 Claims
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1. A radio transmitting antenna comprised of:
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an elongated conductive member having its ends in generally fixed spaced relationship and having an effective electrical length generally equal to λ
/2 at the desired frequency of operation;means at one end of said conductive member for coupling said end of said conductive member to at least a transmitter tuned to said frequency; and elongated generally rigid electrical insulating means extending beyond at least one end of said conductive member, the amount of extension being adjustable whereby said antenna may be elongated independently of the length of the conductive member and may be supported in any position by having the ends of said antenna engage opposed surfaces of a building. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 28, 29, 30)
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10. A radio transmitting antenna comprised of;
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an elongated electrically conductive member including a rigid linear portion and a multiturn coil portion immediately adjacent one end of said linear portion and having one of its terminals connected to said one end of said linear portion; the two portions coacting so as to have an effective electrical length of λ
/2 so as to be generally resonant at the desired frequency of operation; anda multi-turn coil of coaxial cable having one end electrically coupled to said coil portion and the other end adapted to be connected to a transmitter and/or receiver. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A vertical radio antenna comprised of an elongated electrically conductive member having an effective electrical length generally equal to λ
- /2 including first and second linear portions in axially aligned relationship;
a first multi-turn coil axial with said linear members and having its terminals connected respectively to the adjacent ends of said linear portions;
a second multi-turn coil coaxial with and adjacent to the end of one of said linear members remote from said first coil and having a terminal connected to said remote end;
a third coil coaxial with said second coil and having one terminal connected to the other terminal of said second coil;
a coil of coaxial cable in axial alignment with said linear portions and said first and second coils;
the shield of the adjacent end of said coaxial cable being connected to the other terminal of said third coil and the center conductor of said end of said coaxial cable being connected to the other terminal of said third cable;
the other end of said coaxial cable being adapted to be connected to a radio transmitter and/or receiver. - View Dependent Claims (23, 24)
- /2 including first and second linear portions in axially aligned relationship;
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25. A radio transmitting antenna comprised of:
- an elongated electrically conductive member including a linear portion and a multi-turn coil portion electrically associated with said linear portion to increase the effective electrical length thereof, the linear portion being generally on the axis of said coil portion, the two portions having an effective electrical length λ
/2 so as to be resonant at the approximate desired frequency of operation;
an electrically conductive sleeve coaxial with and having an inner diameter greater than the outer diameter of said multi-turn coil portion; and
means supporting said sleeve for adjustment axially relative to said coil portion whereby the resonant frequency of said antenna can be easily adjusted. - View Dependent Claims (26, 27)
- an elongated electrically conductive member including a linear portion and a multi-turn coil portion electrically associated with said linear portion to increase the effective electrical length thereof, the linear portion being generally on the axis of said coil portion, the two portions having an effective electrical length λ
Specification