An investigation into some aspects of Jovian decametric radiation
- Authors: Hill, I. E.
- Date: 1969
- Subjects: Jupiter (Planet) , Radiation , Magnetosphere
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5552 , http://hdl.handle.net/10962/d1015034
- Description: This thesis describes observations of the flne structure in Jovian decametric radiation made at Grahamstown during the 1967-68 apparition. It was found that pulses with duration less than 0.5 milliseconds were common during fine structure storms. The restrictions placed on the source for different theories of origin of the short pulses are discussed. The variation of the probability of occurrence from year to year is analysed on the assumption that the radiation is found in directions fixed with respect to the planet's magnetic field. It is concluded that there is a factor other than the declination of Earth and the Io effect which controls the probability of occurrence. A detailed analysis suggests a beam width of 3° in latitude at Jupiter but further work is necessary to check this.
- Full Text:
- Date Issued: 1969
- Authors: Hill, I. E.
- Date: 1969
- Subjects: Jupiter (Planet) , Radiation , Magnetosphere
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5552 , http://hdl.handle.net/10962/d1015034
- Description: This thesis describes observations of the flne structure in Jovian decametric radiation made at Grahamstown during the 1967-68 apparition. It was found that pulses with duration less than 0.5 milliseconds were common during fine structure storms. The restrictions placed on the source for different theories of origin of the short pulses are discussed. The variation of the probability of occurrence from year to year is analysed on the assumption that the radiation is found in directions fixed with respect to the planet's magnetic field. It is concluded that there is a factor other than the declination of Earth and the Io effect which controls the probability of occurrence. A detailed analysis suggests a beam width of 3° in latitude at Jupiter but further work is necessary to check this.
- Full Text:
- Date Issued: 1969
A 22 GHz radio telescope
- Authors: Mutch, Laurence Ian
- Date: 1976
- Subjects: Radio telescopes , Paraboloid , Radio astronomy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5532 , http://hdl.handle.net/10962/d1012919
- Description: This thesis reports on the design, construction, testing and operation of the spectral line and continuum receivers built for the 22 GHz Radio Telescope. First results from 'the telescope were obtained and have been analysed to give an estimate of system efficiency. Tests have been performed on the front end and in particular on the 22 GHz mixer in order to determine the minimum detectable temperature. The Sun, Moon and major planets are sources suitable for antenna alignment and consequently a literature survey of emission at 22 GHz from elements of the Solar system has been made.
- Full Text:
- Date Issued: 1976
- Authors: Mutch, Laurence Ian
- Date: 1976
- Subjects: Radio telescopes , Paraboloid , Radio astronomy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5532 , http://hdl.handle.net/10962/d1012919
- Description: This thesis reports on the design, construction, testing and operation of the spectral line and continuum receivers built for the 22 GHz Radio Telescope. First results from 'the telescope were obtained and have been analysed to give an estimate of system efficiency. Tests have been performed on the front end and in particular on the 22 GHz mixer in order to determine the minimum detectable temperature. The Sun, Moon and major planets are sources suitable for antenna alignment and consequently a literature survey of emission at 22 GHz from elements of the Solar system has been made.
- Full Text:
- Date Issued: 1976
The performance of a 22 GHz radio telescope
- Authors: Gaylard, Michael John
- Date: 1977
- Subjects: Radio telescopes , Paraboloid
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5520 , http://hdl.handle.net/10962/d1011946 , Radio telescopes , Paraboloid
- Description: The performance of the Rhodes 22 GHz radio telescope and its improvement are discussed in this thesis. The reflector surfaces of the Cassegrain antenna were surveyed and the surface errors minimised, while the magnitude of thermal and gravitational defomations was calculated. The design and operation of the microwave front end has been improved, and the mixer performance characterised. The continuum and spectral line receivers and their sensitivity are described. The aperture efficiency, which has been raised from 0,47 to 0,57, was deduced from solar and lunar observations and atmospheric attenuation measurements. The antenna beam pattern was also obtained from the observations, with the aid of a computer program, and is compared to that predicted for the telescope.
- Full Text:
- Date Issued: 1977
- Authors: Gaylard, Michael John
- Date: 1977
- Subjects: Radio telescopes , Paraboloid
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5520 , http://hdl.handle.net/10962/d1011946 , Radio telescopes , Paraboloid
- Description: The performance of the Rhodes 22 GHz radio telescope and its improvement are discussed in this thesis. The reflector surfaces of the Cassegrain antenna were surveyed and the surface errors minimised, while the magnitude of thermal and gravitational defomations was calculated. The design and operation of the microwave front end has been improved, and the mixer performance characterised. The continuum and spectral line receivers and their sensitivity are described. The aperture efficiency, which has been raised from 0,47 to 0,57, was deduced from solar and lunar observations and atmospheric attenuation measurements. The antenna beam pattern was also obtained from the observations, with the aid of a computer program, and is compared to that predicted for the telescope.
- Full Text:
- Date Issued: 1977
The construction of a swept-frequency polarimeter for observing decametric radiation from Jupiter
- Authors: Baker, Dirk E.
- Date: 1970-01
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/447507 , vital:74652
- Description: This thesis describes the design and construction of a swept-frequency polarimeter for observing Jupiter’s decametric radiation in the frequency range from 15 to 45 MHz. The frequency band is tuned in two parts using two receivers for observing the left- and right-circular components of the radiation in the 15 to 26 MHz range and two receivers for observing the circular components in the 30 to 45 MHz range. The receivers are tuned electronically by means of varactor diodes and are of novel design in that they do not have any intermediate-frequency stages. The frequency band can be swept 10 times per second or 100 times per second. The antennas used for the polarimeter are helical beam antennas, two for each of the circular components in the 15 to 26 MHz range and two for the 30 to 45 MHz range. Model studies of the antennas were conducted to establish whether they have suitable characteristics for observing the polarisation of Jupiter’s decametric radiation over a wide frequency range. Many spectral records of Jupiter’s decametric radiation were obtained using a preliminary version of the swept-frequency receiver and a log-periodic dipole antenna. Some of the records are presented and one record which shows an interesting case of Faraday rotation is analysed. , Thesis (MSc) -- Faculty of Science, Physics, 1970
- Full Text:
- Date Issued: 1970-01
- Authors: Baker, Dirk E.
- Date: 1970-01
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/447507 , vital:74652
- Description: This thesis describes the design and construction of a swept-frequency polarimeter for observing Jupiter’s decametric radiation in the frequency range from 15 to 45 MHz. The frequency band is tuned in two parts using two receivers for observing the left- and right-circular components of the radiation in the 15 to 26 MHz range and two receivers for observing the circular components in the 30 to 45 MHz range. The receivers are tuned electronically by means of varactor diodes and are of novel design in that they do not have any intermediate-frequency stages. The frequency band can be swept 10 times per second or 100 times per second. The antennas used for the polarimeter are helical beam antennas, two for each of the circular components in the 15 to 26 MHz range and two for the 30 to 45 MHz range. Model studies of the antennas were conducted to establish whether they have suitable characteristics for observing the polarisation of Jupiter’s decametric radiation over a wide frequency range. Many spectral records of Jupiter’s decametric radiation were obtained using a preliminary version of the swept-frequency receiver and a log-periodic dipole antenna. Some of the records are presented and one record which shows an interesting case of Faraday rotation is analysed. , Thesis (MSc) -- Faculty of Science, Physics, 1970
- Full Text:
- Date Issued: 1970-01
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