CA1067202A - Moving dipole receives test signal in radiation pattern determination system - Google Patents
Moving dipole receives test signal in radiation pattern determination systemInfo
- Publication number
- CA1067202A CA1067202A CA274,338A CA274338A CA1067202A CA 1067202 A CA1067202 A CA 1067202A CA 274338 A CA274338 A CA 274338A CA 1067202 A CA1067202 A CA 1067202A
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- dipole
- telemetry
- receiving
- recording
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
- G01R29/10—Radiation diagrams of antennas
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a system and method for determining the radiation pattern of an antenna through the use of a RELEDOP (Receiving ELEmentary Dipole with Optional Polarity). The advantage of this invention is that it is suitable for measuring the patterns of most antennae, including large aperture antennae requiring measurements to be made at distances of 30 to 60 miles. The method involves transmitting a signal of either horizontal or vertical polarization from the antenna being measured to a receiving dipole coupled to a receiver. The dipole and receiver are towed behind an airborne vehicle in a substantially circular pattern over the antenna. The received signal is telemetered over a VHF link to a receiver and recording device, and the pattern of the antenna is then derived directly from the recording device. By this invention, enough power is transmitted from the antenna to enable a more thorough measurement of the pattern of the antenna then had previously been possible with methods which transmitted from the towed dipole to the antenna.
This invention relates to a system and method for determining the radiation pattern of an antenna through the use of a RELEDOP (Receiving ELEmentary Dipole with Optional Polarity). The advantage of this invention is that it is suitable for measuring the patterns of most antennae, including large aperture antennae requiring measurements to be made at distances of 30 to 60 miles. The method involves transmitting a signal of either horizontal or vertical polarization from the antenna being measured to a receiving dipole coupled to a receiver. The dipole and receiver are towed behind an airborne vehicle in a substantially circular pattern over the antenna. The received signal is telemetered over a VHF link to a receiver and recording device, and the pattern of the antenna is then derived directly from the recording device. By this invention, enough power is transmitted from the antenna to enable a more thorough measurement of the pattern of the antenna then had previously been possible with methods which transmitted from the towed dipole to the antenna.
Description
~067Z0Z
This invention relates to a system and method for determining the radiation pattern of an antenna. The invention is based on the use of what may be termed RELEDOP (Receiving ELEmentary Dipole with Optional Polarity).
Generally, the measurement of radiation patterns is a difficult problem, which requires careful positioning of a radio source of the correct polarization at a specific distance, elevation angle and azimuth relative to the antenna being measured. Historically, measurement of VHF
and HF antenna patterns has been neglected because of the inherent difficulty of making the measurement. Patterns with varying degrees of relevance to real life applications have been derived using mathematical and scale modeling techniques. The accuracy of these are limited by the difficulty of precise modeling of complex environments such as those provided by ships, cities, etc. This problem is particularly severe at HF frequencies where the ground is an inherent part of the antenna. Large aperture antennas are currently utilized, for example, at those frequencies which can be degraded by irregu-larities and inhomogeneities in the ground. These parameters are easily measured prior to the installation of the antenna by measuring the pattern of a standard monopole antenna erected at the proposed antenna site. Proper engineering of an antenna and its optimum utilization in a communications circuit requires accurate knowledge of its radiation pattern.
One method which is known involves the use of what has been termed XELEDOP, or transmitting elementary dipole with optional polarity. This technique consists of an aircraft towing an aerodynamically stable package equipped with a short dipole antenna and transmitter that sequentially trans-mits on a number of frequencies. The signals are received by the antenna being calibrated and their amplitude recorded. This data defines the radiation pattern of the antenna after corrections are made for the pattern of the test dipole, non-linearities in the electronics and variation in distance between the XELEDOP and the antenna being measured. This system has been found to be effective in measuring antenna patterns and the results are well documented.
~067ZOZ
The main disadvantage of the XELEDOP system is that it is difficult to transmit enough power to generate sufficiently strong fields at the unknown antenna to measure all aspects of its pattern. This is particularly true when the measurements must be made at a distance of 30 to 60 miles which is the case for large aperture antennas. In essence, it is technically very difficult to couple energy from the low output impedance XELEDOP transmitter to its short dipole because the dipole has a high input impedance which is highly reactive.
The object of this invention is to permit sufficient power to be generated to enable a more thorough measurement of the antenna radiation pattern to be made. In this invention, the antenna which is being measured is the transmitting antenna, and the dipole is the receiving antenna. Thus, instead of transmitting from the airborne dipole, transmissions are made from the antenna being calibrated and the signals are received by the dipole and receiver, which are towed behind an aircraft in a set pattern above the transmitting antenna. The elementary dipole is coupled directly to the input preamplifier of the receiver, thereby giving a system with high sensitivity. Coupling the input impedance of the dipole to the high input impedance preamplifier is much more efficient than coupling it to a power amplifier with its inherently low output impedance. A VHF telemetry link is employed with the amplitude of the received signal being telemetered in real-time either directly to the aircraft towing the dipole and receiver, or to a ground terminal. The system of this invention is capable of 2, or more, orders of magnitude more sensitivity than that of the XELEDOP, although only 1 watt is transmitted from the ground antenna which is being measured.
Optional polarity is available with the receiving dipole arrange-ment of this invention. The receiver and dipole are towed sufficiently far behind the aircraft so as to provide isolation from the distorting effects of the aircraft fuselage. This allows the polarization of the transmitted signal to be changed from horizontal to vertical.
In accordance with one aspect of this invention there is provided a system for determining the radiation pattern of an antenna comprising a transmitter coupled to said antenna, a receiving elementary dipole adapted to be orien~ed to receive either vertical or horizontal polarized signals coupled to a receiving means for detecting the amplitude of the signal, and adapted to be moved in a determined manner about the antenna, means for recording the position of the dipole with respect to the antenna, a telemetry transmitter coupled to said receiving means, and a telemetry receiving and recording arrangement having a recording device adapted to co-ordinate and record the amplitude of the signal and the position of the dipole to permit the derivation of the radiation pattern directly from said recording device.
In accordance with another aspect of this invention there is provided a method of determining the radiation pattern of an antenna com-prising the steps of transmitting a signal from the antenna, receiving the signal with an elementry dipole coupled to a receiving means adapted to detect the amplitude of the signal and moved in a determined manner about the antenna, recording the position of the dipole with respect to the antenna, transmit-ting the amplitude of said signal from a telemetry transmitter coupled to the receiving means to a telemetry receiving and recording system having a recor-ding device, co-ordinating and recording on said device the amplitude of the signal and the position of the dipole and deriving the radiation pattern directly from the recording device.
Reference should be had to the drawings which are as follows:-Figure 1 is a schematic of the RELEDOP, or receiving elementarydipole with optional polarity;
Figure 2 is a sketch of the configuration employed during measure-ment of the antenna radiation pattern;
Figure 3 is a block diagram of the total system configuration;
Figure 4 is a block diagram of the telemetry receiving and record-ing arrangement.
Referring to Figure 1 it can be seen that a preferredembodiment of the RELEDOR, generally indicated at 20, is comprised of a 6 foot dipole antenna 10,10' ~ith end spheres 12,12' connected to a receiver (not shown), housed in a fiberglass spherical chamber 14, having a diameter of six inches. The spherical chamber 14 is connected to a towing rope 15 by the use of a FIBERGLAS (trade mark) bridle 16. This allows for adjust-ment and orientation of the dipole antenna.
Referring to Figure 2, it can be seen that the receiver and dipole are towed as part of a flight package 20 behind an aircraft 21, which flies, for the most part, in a circular pattern at a fixed distance from the antenna 25 at various altitudes.
The dipole can be oriented to accept either vertical or horizontal polarized signals. A departure from this normal flight plan is necessarily made to obtain the vertical pattern of the antenna. The aircraft in this case flies over the antenna in straight lines at a constant altitude. ~ radar 26, which can be deployed adjacent to the antenna 25, is used to measure the position of the aircraft, and consequently, of the flight package. This information is recorded with time markers, and the information i5 subsequently analyzed in order to derive direct readings from the ultimate recording mechanism.
Figure 3 represents a block diagram of the flight package 20, which comprises the dipole and receiYer. Each half 10,10' of the six foot dipole antenna is connected to the high impedance input of a push-pull preamplifier 30. The output of the preamplifier 30 is stepped down to 50 ohms and fed into a balanced mixer 31. The signals are then mixed with the output of a high frequency oscillator 33, and amplified by an IF amplifier 35. Detection of the signal takes place in the ~ ~ 4 linear detector and the output of the linear detector 36 controls the frequency of the linear voltage controlled oscillator 37 output which in turn modulates the slgnal transmitted by the telemetry trans~ltter 38. The telemetry transmitter 38 can be an FM telemetr~ trans~itter. The overall ~oltage gain of the receiver is in the order of 70 dB.
-4a-Referring to Figure 4, there is shown a blo~k diagram of the tele-metry receiving and recording arrangement, having a recording device, such as a chart recorder 40. The audio output of the telemetry receiver 41 drives a frequency to voltage converter 42 whose output is displayed on the chart recorder 40. The time markers are also recorded in the chart recorder 40, and are correlated with the radar fixes recorded during the measurement interval. Since the linearity of the system is maintained from the input of the RELEDOP receiver to the output of the telemetry receiver 41 and frequency to voltage converter 42, the pattern of the antenna can be derived directly from the chart recorder 40.
This invention relates to a system and method for determining the radiation pattern of an antenna. The invention is based on the use of what may be termed RELEDOP (Receiving ELEmentary Dipole with Optional Polarity).
Generally, the measurement of radiation patterns is a difficult problem, which requires careful positioning of a radio source of the correct polarization at a specific distance, elevation angle and azimuth relative to the antenna being measured. Historically, measurement of VHF
and HF antenna patterns has been neglected because of the inherent difficulty of making the measurement. Patterns with varying degrees of relevance to real life applications have been derived using mathematical and scale modeling techniques. The accuracy of these are limited by the difficulty of precise modeling of complex environments such as those provided by ships, cities, etc. This problem is particularly severe at HF frequencies where the ground is an inherent part of the antenna. Large aperture antennas are currently utilized, for example, at those frequencies which can be degraded by irregu-larities and inhomogeneities in the ground. These parameters are easily measured prior to the installation of the antenna by measuring the pattern of a standard monopole antenna erected at the proposed antenna site. Proper engineering of an antenna and its optimum utilization in a communications circuit requires accurate knowledge of its radiation pattern.
One method which is known involves the use of what has been termed XELEDOP, or transmitting elementary dipole with optional polarity. This technique consists of an aircraft towing an aerodynamically stable package equipped with a short dipole antenna and transmitter that sequentially trans-mits on a number of frequencies. The signals are received by the antenna being calibrated and their amplitude recorded. This data defines the radiation pattern of the antenna after corrections are made for the pattern of the test dipole, non-linearities in the electronics and variation in distance between the XELEDOP and the antenna being measured. This system has been found to be effective in measuring antenna patterns and the results are well documented.
~067ZOZ
The main disadvantage of the XELEDOP system is that it is difficult to transmit enough power to generate sufficiently strong fields at the unknown antenna to measure all aspects of its pattern. This is particularly true when the measurements must be made at a distance of 30 to 60 miles which is the case for large aperture antennas. In essence, it is technically very difficult to couple energy from the low output impedance XELEDOP transmitter to its short dipole because the dipole has a high input impedance which is highly reactive.
The object of this invention is to permit sufficient power to be generated to enable a more thorough measurement of the antenna radiation pattern to be made. In this invention, the antenna which is being measured is the transmitting antenna, and the dipole is the receiving antenna. Thus, instead of transmitting from the airborne dipole, transmissions are made from the antenna being calibrated and the signals are received by the dipole and receiver, which are towed behind an aircraft in a set pattern above the transmitting antenna. The elementary dipole is coupled directly to the input preamplifier of the receiver, thereby giving a system with high sensitivity. Coupling the input impedance of the dipole to the high input impedance preamplifier is much more efficient than coupling it to a power amplifier with its inherently low output impedance. A VHF telemetry link is employed with the amplitude of the received signal being telemetered in real-time either directly to the aircraft towing the dipole and receiver, or to a ground terminal. The system of this invention is capable of 2, or more, orders of magnitude more sensitivity than that of the XELEDOP, although only 1 watt is transmitted from the ground antenna which is being measured.
Optional polarity is available with the receiving dipole arrange-ment of this invention. The receiver and dipole are towed sufficiently far behind the aircraft so as to provide isolation from the distorting effects of the aircraft fuselage. This allows the polarization of the transmitted signal to be changed from horizontal to vertical.
In accordance with one aspect of this invention there is provided a system for determining the radiation pattern of an antenna comprising a transmitter coupled to said antenna, a receiving elementary dipole adapted to be orien~ed to receive either vertical or horizontal polarized signals coupled to a receiving means for detecting the amplitude of the signal, and adapted to be moved in a determined manner about the antenna, means for recording the position of the dipole with respect to the antenna, a telemetry transmitter coupled to said receiving means, and a telemetry receiving and recording arrangement having a recording device adapted to co-ordinate and record the amplitude of the signal and the position of the dipole to permit the derivation of the radiation pattern directly from said recording device.
In accordance with another aspect of this invention there is provided a method of determining the radiation pattern of an antenna com-prising the steps of transmitting a signal from the antenna, receiving the signal with an elementry dipole coupled to a receiving means adapted to detect the amplitude of the signal and moved in a determined manner about the antenna, recording the position of the dipole with respect to the antenna, transmit-ting the amplitude of said signal from a telemetry transmitter coupled to the receiving means to a telemetry receiving and recording system having a recor-ding device, co-ordinating and recording on said device the amplitude of the signal and the position of the dipole and deriving the radiation pattern directly from the recording device.
Reference should be had to the drawings which are as follows:-Figure 1 is a schematic of the RELEDOP, or receiving elementarydipole with optional polarity;
Figure 2 is a sketch of the configuration employed during measure-ment of the antenna radiation pattern;
Figure 3 is a block diagram of the total system configuration;
Figure 4 is a block diagram of the telemetry receiving and record-ing arrangement.
Referring to Figure 1 it can be seen that a preferredembodiment of the RELEDOR, generally indicated at 20, is comprised of a 6 foot dipole antenna 10,10' ~ith end spheres 12,12' connected to a receiver (not shown), housed in a fiberglass spherical chamber 14, having a diameter of six inches. The spherical chamber 14 is connected to a towing rope 15 by the use of a FIBERGLAS (trade mark) bridle 16. This allows for adjust-ment and orientation of the dipole antenna.
Referring to Figure 2, it can be seen that the receiver and dipole are towed as part of a flight package 20 behind an aircraft 21, which flies, for the most part, in a circular pattern at a fixed distance from the antenna 25 at various altitudes.
The dipole can be oriented to accept either vertical or horizontal polarized signals. A departure from this normal flight plan is necessarily made to obtain the vertical pattern of the antenna. The aircraft in this case flies over the antenna in straight lines at a constant altitude. ~ radar 26, which can be deployed adjacent to the antenna 25, is used to measure the position of the aircraft, and consequently, of the flight package. This information is recorded with time markers, and the information i5 subsequently analyzed in order to derive direct readings from the ultimate recording mechanism.
Figure 3 represents a block diagram of the flight package 20, which comprises the dipole and receiYer. Each half 10,10' of the six foot dipole antenna is connected to the high impedance input of a push-pull preamplifier 30. The output of the preamplifier 30 is stepped down to 50 ohms and fed into a balanced mixer 31. The signals are then mixed with the output of a high frequency oscillator 33, and amplified by an IF amplifier 35. Detection of the signal takes place in the ~ ~ 4 linear detector and the output of the linear detector 36 controls the frequency of the linear voltage controlled oscillator 37 output which in turn modulates the slgnal transmitted by the telemetry trans~ltter 38. The telemetry transmitter 38 can be an FM telemetr~ trans~itter. The overall ~oltage gain of the receiver is in the order of 70 dB.
-4a-Referring to Figure 4, there is shown a blo~k diagram of the tele-metry receiving and recording arrangement, having a recording device, such as a chart recorder 40. The audio output of the telemetry receiver 41 drives a frequency to voltage converter 42 whose output is displayed on the chart recorder 40. The time markers are also recorded in the chart recorder 40, and are correlated with the radar fixes recorded during the measurement interval. Since the linearity of the system is maintained from the input of the RELEDOP receiver to the output of the telemetry receiver 41 and frequency to voltage converter 42, the pattern of the antenna can be derived directly from the chart recorder 40.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A system for determining the radiation pattern of an antenna com-prising a transmitter coupled to said antenna, a receiving elementary dipole adapted to be oriented to receive either vertical or horizontal polarized signals coupled to a receiving means for detecting the amplitude of the signal radiated by said antenna, and adapted to be moved in a determined manner about the antenna, means for recording the position of the dipole with respect to the antenna, a telemetry transmitter coupled to said receiving means, and a telementry receiving and recording arrangement having a record-ing device adapted to co-ordinate and record the amplitude of the signal and the position of the dipole relative to said antenna to permit the deriva-tion of the radiation pattern directly from said recording device.
2. A system according to claim 1 wherein the dipole is attached to a spherical chamber containing the receiving means, and has a bridle for secur-ing said spherical chamber to a rope for movement about the antenna.
3. A system according to claim 2 wherein the receiving means comprises a preamplifier having its output connected to a mixer, a high frequency os-cillator connected to said mixer, the output of said mixer connected to an IF amplifier, the output of said IF amplifier coupled to a linear detector, and the output of said linear detector connected to a voltage controlled os-cillator.
4. A system according to claim 3, wherein the means for recording the position of the dipole comprises a radar and a source of time markers.
5. A system according to claim 4 wherein the telemetry receiving and recording arrangement comprises a telemetry receiver coupled to a frequency to voltage converter connected to a chart recorder which is adapted to co-ordinate and record the amplitude of the signal and the position of the dipole to permit the derivation of the radiation pattern directly from said chart recorder.
6. A system according to claim 5, wherein the telemetry transmitter is an FM telemetry transmitter and the telemetry receiving and recording ar-rangement is an FM telemetry arrangement.
7. A method of determining the radiation pattern of an antenna com-prising the steps of transmitting a signal from the antenna, receiving the signal with an elementary dipole coupled to a receiving means adapted to detect the amplitude of the signal, moving the dipole in a determined manner about the antenna, recording the position of the dipole with respect to the antenna, transmitting the detected amplitude of said signal from a telemetry transmitter coupled to the receiving means to a telemetry receiving and record-ing system having a recording device, co-ordinating and recording on said recording device the amplitude of the signal and the position of the dipole and deriving the radiation pattern directly from the recording device.
8. The method of claim 7 wherein said elementary dipole and receiving means are towed behind an aircraft about the antenna in a circular pattern at a fixed distance from the antenna at different altitudes.
9. The method of claim 8 wherein said elementary dipole and receiving means are towed behind an airborne vehicle about the antenna in straight lines at a constant altitude to derive a vertical radiation pattern and in circles to derive the horizontal radiation pattern.
10. The method of claim 7 wherein the position of the dipole with re-spect to the antenna is measured by radar, time markers are recorded and correlated with the radar fixes, and said time markers are recorded on a chart recorder.
11. A system for determing the radiation pattern of an antenna, comprising a transmitter coupled to said antenna, a flight package adapted to be towed by an aircraft a distance therefrom via a non-conductive line, said flight package comprising a receiving elementary dipole capable of being oriented to receive either vertical or horizontal polarized signals, a receiving means of said flight package connected to said dipole for detecting the amplitude of signals radiated by said antenna and received by said dipole, said receiving means including a pre-amplifier, wherein said received signal is directly coupled to the high-impedance input of said pre-amplifier, a telemetry transmitter of said flight package coupled to the output of said receiving means for transmitting telemetry signals corresponding to the amplitude of signals received by said dipole, a telemetry receiver spaced from said flight package for receiving said telemetry signals, and a recording apparatus associated with said telemetry receiver for recording the amplitude of the signals received by said dipole and the position of said dipole relative to said antenna to permit derivation of the radiation pattern of said antenna from said recording device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA274,338A CA1067202A (en) | 1977-03-21 | 1977-03-21 | Moving dipole receives test signal in radiation pattern determination system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA274,338A CA1067202A (en) | 1977-03-21 | 1977-03-21 | Moving dipole receives test signal in radiation pattern determination system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1067202A true CA1067202A (en) | 1979-11-27 |
Family
ID=4108200
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA274,338A Expired CA1067202A (en) | 1977-03-21 | 1977-03-21 | Moving dipole receives test signal in radiation pattern determination system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1067202A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4884078A (en) * | 1986-08-01 | 1989-11-28 | Hughes Aircraft Company | Antenna test and measurement system |
| CN107179449A (en) * | 2017-04-20 | 2017-09-19 | 中国人民解放军海军工程大学 | A kind of short-wave receiving antenna 3 D stereo directional diagram aerial mobile measuring system and method |
| CN110058092A (en) * | 2019-04-29 | 2019-07-26 | 湖南国科微电子股份有限公司 | A kind of antenna detection circuit based on CMOS technology and the chip and terminal device with it |
-
1977
- 1977-03-21 CA CA274,338A patent/CA1067202A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4884078A (en) * | 1986-08-01 | 1989-11-28 | Hughes Aircraft Company | Antenna test and measurement system |
| CN107179449A (en) * | 2017-04-20 | 2017-09-19 | 中国人民解放军海军工程大学 | A kind of short-wave receiving antenna 3 D stereo directional diagram aerial mobile measuring system and method |
| CN107179449B (en) * | 2017-04-20 | 2019-09-20 | 中国人民解放军海军工程大学 | A kind of short-wave receiving antenna 3 D stereo directional diagram aerial mobile measuring system and method |
| CN110058092A (en) * | 2019-04-29 | 2019-07-26 | 湖南国科微电子股份有限公司 | A kind of antenna detection circuit based on CMOS technology and the chip and terminal device with it |
| CN110058092B (en) * | 2019-04-29 | 2022-04-19 | 湖南国科微电子股份有限公司 | Antenna detection circuit, chip and terminal equipment |
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