GB2271669A

GB2271669A - Control of antennas

Info

Publication number: GB2271669A
Application number: GB9220739A
Authority: GB
Inventors: David Arends; Colin Edwards
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-10-02
Filing date: 1992-10-02
Publication date: 1994-04-20
Also published as: GB9220739D0

Abstract

In an arrangement for controlling the position of an antenna, control signals determining antenna orientation are sent to the antenna 10 via a cable which also acts as a reception cable for signals, such as television signals, received by the antenna. The antenna may be a dish which can receive signals from different satellites. The antenna may alternatively be a transmitting antenna. <IMAGE>

Description

CONTROL OF ANTENNAE The present invention relates to controlling an antenna and is concerned particularly although not exclusively with controlling the position of a receiving antenna.

Often to receive a signal, such as an electromagnetic signal, a parabolic dish is used as an antenna. The parabolic dish is able to gather radiation incident upon its parabolic surface and focus the radiation at a point spaced from that surface.

A common use for this kind of parabolic or "dish" receiver is in the reception of television signals which are transmitted from a terrestrial station to a satellite mounted in geostationary orbit above the earth, and reflected or re-transmitted by the satellite to be received by terrestrial receivers. The television signals from the satellite are incident upon a receiving dish which may, for example, be mounted on the exterior of a house, and are collected and focused by the dish whereupon they are transmitted to a receiving/decoding unit located indoors before being relayed to a television set in a conventional way.

Such equipment has become increasingly popular in recent years and a number of different satellites are now reflecting or re-transmitting television signals from their positions in geostationary orbits above the earth.

However, in order for the parabolic dish receiver to receive television signals from a particular orbiting satellite it is necessary that the dish is made to point substantially towards that satellite.

Thus for owners of dish receiving equipment who wish to receive signals from more than one satellite it is necessary either to have more than one dish, or to have one dish which is moveable between the different orientations necessary to receive television signals from the various satellites.

Conventionally such moveable dish receivers include a motor arranged in use to alter the orientation of the dish, and control means arranged to control the degree to which the motor moves the dish, according to which of the orbiting satellites it is desired to receive television signals from. The motor is conventionally situated on or adjacent the dish, and the control means is conventionally situated indoors, adjacent the receiver/decoder apparatus.

The motor and control unit are conventionally linked by a multi-core cable.

When it is desired to alter the orientation of the dish to receive signals from different satellites, the user conventionally operates a remote handset which indicates to the control unit which satellite is required.

The control unit then sends a control signal along the multi-core cable to the motor causing the motor to alter the orientation of the dish by moving it a predetermined number of degrees along a pre-set arc so that a signal from a chosen satellite orbiting at a particular longitude coordinate may be received. Feedback signals from the motor to the control unit indicate the position of the dish to the control unit so that the dish can be moved by the correct number of degrees of arc.

According to one aspect of the present invention there is provided control apparatus for controlling the orientation of an antenna, the antenna being arranged, in use, to receive a reception signal and to transmit the reception signal to receiver apparatus along reception cable, the apparatus comprising motor means, arranged in use to move the antenna and control means arranged to control the extent to which the antenna is moved, wherein the control means is arranged to send a control signal to the motor means along the reception cable.

Preferably the antenna comprises a parabolic or other dish-type antennae.

Preferably the antennae is arranged to receive an electro-magnetic signal such as a television signal.

In a preferred arrangement the apparatus is arranged to control the orientation of the parabolic antennae such that the antenna receives electro-magnetic signals from one of a number of orbiting satellite transmitters situated at different locations above the surface of the earth.

The control signal may comprise one of a number of signals, at least one of which corresponds to a particular orientation of the antenna.

Preferably the control signal comprises an electrical control signal.

In a preferred arrangement, the control signal is sent to the motor means via a co-axial cable.

Preferably the cable along which the control signal is sent from the control means to the motor means is the same cable along which is sent the reception signal from the antenna to the receiver apparatus.

Preferably the control signal comprises one or more electrical pulses. In a preferred arrangement the control signal comprises a series of electrical pulses.

Preferably different sets of electrical pulses are arranged to represent different orientations of the antenna.

Preferably the antenna is provided with detector means arranged to detect electromagnetic signals received by the antenna. The detector means may comprise a low noise block (LNB).

In a preferred arrangement the electronic pulses represent changes in electrical voltage or in electrical current between a first value which is used to instruct the detector means to detect electromagnetic signals having a first kind of polarisation and a second value which is used to instruct the detector means to detect electromagnetic signals having a second kind of polarisation.

Preferably the first and second kinds of polarisation are horizontal and vertical polarisations respectively.

In a preferred arrangement the control means comprises conventional receiver apparatus. Preferably, the control signal is sent from the control means to the motor means in the form of a number of electrical pulses which pulses represent transitions in electrical voltage between a first voltage level arranged in use to instruct the detector means to detect received electromagnetic signals of a first polarisation, and a second voltage level arranged in use to instruct the detector to detect received electro-magnetic signals of a second polarisation.

The motor means is preferably provided with a motor controller arranged to receive the control signals from the control means and to operate the motor according to the nature of the control signal. Preferably the motor controller is located integral with or adjacent the motor means.

In a preferred arrangement there is provided a remote handset, operable by a user in which is stored at least one and preferably several command codes, which command codes correspond to the different orientations which must be adopted by the antenna to receive electromagnetic signals from different orbiting satellite transmitters.

The or each command code may comprise a stream of pulses which is transmitted from the handset to the control means. The control means is preferably arranged to receive the command code and to switch correspondingly between first and second levels of electrical voltage used to instruct the detector of the antenna to detect electromagnetic signals having first and second polarisations respectively.

The control means may comprise means to effect switching of the levels of voltage. Alternatively or additionally there may be provided additional switching means to effect switching of the levels of voltage.

Preferably the switching of the control means between first and second electrical voltage levels produces a pulse stream corresponding to the position code which pulse stream is transmitted to the motor means via the reception cable. The motor controller is preferably arranged to interpret a particular pulse stream as an instruction to operate the motor so as to move the antenna by a particular number of degrees of arc along a pre-set arc.

Alternatively or additionally the handset may store a command code which is interpreted by the motor controller as an instruction to calibrate the position of the antenna. Preferably the handset stores at least one command code which is interpreted by the motor controller as an instruction to move the antenna continuously until the command ceases. The handset may include at least one command code which is interpreted by the motor controller as an instruction to switch the detector.

According to a second aspect of the present invention there is provided control apparatus for controlling the orientation of a transmitter, the transmitter being arranged in use to transmit a transmission signal which transmission signal is sent to the transmitter, along a transmission cable, the apparatus comprising motor means, arranged in use to move the transmitter and control means arranged to control the extent to which the transmitter is moved, wherein the control means is arranged to send a control signal to the motor means along the transmission cable.

Other features of the invention may be as stated in any statement herein.

According to a third aspect of the present invention there is provided a method of controlling the orientation of an antenna, the antenna being arranged, in use to receive a reception signal and to transmit the reception signal to receiver apparatus along a reception cable, the method comprising changing the orientation of the antennae with motor means and controlling the motor means by sending a control signal to the motor means along the reception cable.

Preferably the method comprises a method of controlling the orientation of a parabolic or other dishtype antenna. The method may comprise a method of controlling the orientation of an antenna which antenna is arranged to receive an electro-magnetic signal such as a television signal.

Preferably the method comprises changing the orientation of an antenna to receive signals from one or more orbiting satellite transmitters.

In a preferred arrangement the method comprises sending a control signal to the motor which control signal comprises one or more electrical pulses. The method may comprise sending electrical pulses which pulses are formed by transitions between voltage or current levels. The method preferably includes sending pulses which pulses are formed by transitions between values of electrical voltage or electrical current which values are used to instruct a detector of the antenna to detect either electro-magnetic signals having a first polarisation or electro-magnetic signals having a second polarisation.

The invention also includes any combination of the features or limitations referred to herein.

The invention may be carried into practice in various ways but an embodiment will now be described by way of example with reference to the accompanying diagrammatic drawings in which: Figure 1 shows a prior art apparatus for controlling the orientation of an antenna, and Figure 2 shows an apparatus for controlling the orientation of an antenna according to an embodiment of the present invention.

Referring firstly to Figure 1, this shows a prior art system for controlling the orientation of a parabolic dish antenna 10. Conventionally the dish 10 is mounted on the exterior of a building 11. As television signals from an orbiting satellite are incident upon the dish 10 they become focused at a detector 12 known as a low noise block (LNB). The detected television signals are then sent down a co-axial cable 13 to a receiver/decoder 14 which receives and decodes the signals before relaying them to a television set (not shown). A remote hand set 15 is conventionally used to select which of the transmitted television channels which make up the television signal is to be received and decoded for viewing on the television set.Although, as stated above, a number of television channels are transmitted by an orbiting satellite, there are also a number of different orbiting satellites, each situated in a different location in geostationary orbit above the earth. In order that the dish antenna can be made to receive television signals from a different orbiting satellite, the dish must be made to point substantially towards that satellite. This is achieved by altering the orientation of the dish 10, along a predetermined arc, by the required number of degrees of arc.

The prior art system shown in Figure 1 achieves this with the use of a positioning device 16 which is linked to a motor unit 17. The motor unit 17 controls the movement of the dish 10 along a predetermined arc in response to a control signal sent by the positioning device 16 along a multi-core cable 18. As the motor unit 17 moves the dish 10 the position of the dish 10 is relayed to the positioning device 16 along the multi-core cable 18. When the dish 10 is correctly positioned, the positioning device 16 signals to the motor unit 17 to cease moving the dish 10. The longitude co-ordinates of each of the available orbiting satellites are stored in the positioning device 16 and the desired satellite is selected by a second remote handset 19.

Referring now to Figure 2, this shows a system for controlling the orientation of an antenna according to an embodiment of the present invention.

In the conventional manner a parabolic dish antenna 10 receives incident television signals from a transmitting orbiting satellite (not shown) and focuses those signals to a detector 12 which comprises an LNB.

The detected television signals are relayed along a coaxial cable 13 through a wall of building 11 in the conventional way to a receiver/decoder 14 which receives and decodes the television signals before relaying them to a television set (not shown). The detector is conventionally arranged to detect television signals having either horizontal polarisation or vertical polarisation and can be switched between the two upon receipt of a polarisation signal from the receiver/decoder 14. The desired channel of the many which are transmitted by each satellite is chosen by a user using a remote handset 15. If it is desired to change the orientation of the dish 10 to receive television signals from a different orbiting satellite, the following procedure is adopted.

The user, using a second hand-set 20 selects the desired satellite. The hand-set 20 then sends a unique code identifying the desired satellite in the form of an infra-red signal to the receiver/decoder 14. The receiver/decoder 14 indicates to a motor control unit 21 which of the satellites is desired by sequentially switching the polarisation signal which, as described above, is conventionally used to instruct the detector 12 to detect either horizontally or vertically polarised television signals.

In more detail, this entails the production of a sequence of voltage pulses in the coaxial cable 13. For example, a voltage of 12 volts in the cable 13 might conventionally instruct the detector 12 to detect horizontally polarised television signals and a voltage of 16 volts in the cable 13 might instruct the detector 12 to detect vertically polarised television signals. By switching between 12 volts and 16 volts a pulse stream can be transmitted to the motor controller 21. Each distinct pulse stream is a unique identity code identifying a particular satellite to the motor controller 21 which, upon receipt of a particular identity code, moves the dish 10 by the appropriate extent along a preset arc. The dish 10 can then be made to receive television signals from any one of number of satellites located at particular longitude co-ordinates in orbit above the earth.

The positions of all of the available satellites are stored in the motor controller.

The apparatus described above provides a convenient means of controlling the orientation of a dish antenna.

The apparatus can be readily made to operate with existing fixed dish equipment with a minimum of installation. No additional wiring is required into the building since the control signal which controls the movement of the dish is transmitted along the existing coaxial cable. In addition the motor controller receives power in the same way as does the detector, i.e. via the coaxial cable.

Although the above described apparatus involves the controlling of the orientation of an antenna for receiving television signals, it will be understood by those skilled in the art that a similar system could be employed to control the orientation of a transmitter, whilst not departing from the scope of the invention.

Claims

1. Control apparatus for controlling the orientation of an antenna, the antenna being arranged, in use, to receive a reception signal and to transmit the reception signal to receiver apparatus along reception cable, the apparatus comprising motor means, arranged in use to move the antenna and control means arranged to control the extent to which the antenna is moved, wherein the control means is arranged to send a control signal to the motor means along the reception cable.

2. Apparatus according to claim 1, wherein the antenna comprises a parabolic or other dish-type antennae.

3. Apparatus according to claim 1 or 2, wherein the antenna is arranged to receive an electro-magnetic signal such as a television signal.

4. Apparatus according to any of the preceding claims, wherein the apparatus is arranged to control the orientation of the antenna such that the antenna receives electro-magnetic signals from one of a number of orbiting satellite transmitters situated at different locations above the surface of the earth.

5. Apparatus according to any of the preceding claims, wherein the control signal comprises one of a number of signals, at least one of which corresponds to a particular orientation of the antenna.

6. Apparatus according to any of the preceding claims, wherein the control signal comprises an electrical control signal.

7. Apparatus according to any of the preceding claims, wherein the control signal is sent to the motor means via a coaxial cable.

8. Apparatus according to any of the preceding claims, wherein the control signal comprises one or more electrical pulses.

9. Apparatus according to claim 8, wherein the control signal comprises a series of electrical pulses.

10. Apparatus according to claims 8 or 9 wherein different sets of electrical pulses are arranged to represent different orientations of the antenna.

11. Apparatus according to any of the preceding claims, wherein the electrical pulses represent changes in electrical voltage or in electrical current between a first value which is used to instruct the detector means to detect electromagnetic signals having a first kind of polarisation and a second value which is used to instruct the detector means to detect electromagnetic signals having a second kind of polarisation.

12. Apparatus according to claim 11, wherein the first and second kinds of polarisation are horizontal and vertical polarisations respectively.

13. Apparatus according to any of the preceding claims, wherein the antenna is provided with detector means arranged to detect electromagnetic signals received by the antenna.

14. Apparatus according to claim 14, wherein the detector means comprises a low noise block (LNB).

15. Apparatus according to any of the preceding claims, wherein the control means comprises conventional receiver apparatus.

16. Apparatus according to any of the preceding claims, wherein the control signal is sent from the control means to the motor means in the form of a number of electrical pulses which pulses represent transitions in electrical voltage between a first voltage level arranged in use to instruct the detector means to detect received electromagnetic signals of a first polarisation, and a second voltage level arranged in use to instruct the detector to detect received electro-magnetic signals of a second polarisation.

17. Apparatus according to any of the preceding claims, wherein the motor means is provided with a motor controller arranged to receive the control signals from the control means and to operate the motor according to the nature of the control signal.

18. Apparatus according to claim 17, wherein the motor controller is located integral with or adjacent the motor means.

19. Apparatus according to any of the preceding claims, wherein a remote handset is provided, operable by a user in which is stored at least one and preferably several command codes, which command codes correspond to different orientations which must be adopted by the antenna to receive electromagnetic signals from different orbiting satellite transmitters.

20. Apparatus according to claim 19, where the or each command code comprises a stream of pulses which is transmitted from the handset to the control means.

21. Apparatus according to claim 19 or claim 20, wherein the control means is arranged to receive the command code and to switch correspondingly between first and second levels of electrical voltage used to instruct the detector of the antenna to detect electro-magnetic signals having first and second polarisations respectively.

22. Apparatus according to claim 21, wherein the control means comprises means to effect switching of the levels of voltage.

23. Apparatus according to claim 22, wherein additional switching means is provided to effect switching of the levels of voltage.

24. Apparatus according to any of claims 21 to 23, wherein the switching of the control means between first and second electrical voltage levels produces a pulse stream corresponding to a position code which pulse stream is transmitted to the motor means via the reception cable.

25. Apparatus according to claim 24, wherein the motor controller is arranged to interpret a particular pulse stream as an instruction to operate the motor so as to move the antenna by a particular number of degrees of arc along a pre-set arc.

26. Apparatus according to any of claims 19 to 25, wherein the hand set stores a command code which is interpreted by the motor controller as an instruction to calibrate the position of the antenna.

27. Apparatus according to any of claims 19 to 26, wherein the handset stores at least one command code which is interpreted by the motor controller as an instruction to move the antenna continuously until the command ceases.

28. Apparatus according to any one of claims 19 to 27, wherein the handset includes at least one command code which is interpreted by the motor controller as an instruction to switch the detector.

29. Control apparatus for controlling the orientation of a transmitter, the transmitter being arranged in use to transmit a transmission signal which transmission signal is sent to the transmitter, along a transmission cable,, the apparatus comprising motor means, arranged in use to move the transmitter and control means arranged to control the extent to which the transmitter is moved, wherein the control means is arranged to send a control signal to the motor means along the transmission cable.

30. A method of controlling the orientation of an antenna, the antenna being arranged, in use to receive a reception signal and to transmit the reception signal to receiver apparatus along a reception cable, the method comprising changing the orientation of the antenna with motor means and controlling the motor means by sending a control signal to the motor means along the reception cable.

31. The method of claim 31 comprising a method of controlling the orientation of a parabolic or other dishtype antenna.

32. The method of claim 30 or claim 31, wherein the method comprises a method of controlling the orientation of an antenna which antenna is arranged to receive an electro-magnetic signal such as a television signal.

33. The method of claim 30, claim 31 or claim 32, wherein the method comprises changing the orientation of an antenna to receive signals from one or more orbiting satellite transmitters.

34. The method according to any of claims 30 to 33, wherein the method comprises sending a control signal to the motor which control signal comprises one or more electrical pulses.

35. The method according to any of claims 30 to 35, wherein the method includes sending pulses which pulses are formed by transitions between voltage or current levels.

36. The method according to any of claims 30 to 35, wherein the method includes sending pulses, which pulses are formed by transitions between values of electrical voltage or electrical current which values are used to instruct a detector of the antenna to detect either electro-magnetic signals having a first polarisation or electro-magnetic signals having a second polarisation.

37. Control apparatus substantially as herein described with reference to Figure 2.

38. A method of controlling the orientation of an antenna substantially as herein described with reference to Figure 2.