Contributions to radio astronomy

This thesis presents contributions to radio astronomy in the areas of instrumentation, pulsar astronomy and low frequency radio astronomy made over a twenty year period. The contributions in instrumentation include the development of broad-band array telescopes for use at low frequencies, a new control system for the Parkes telescope and a wide-band spectrograph and polarimeter using surface acoustic wave devices. In pulsar astronomy significant contributions include extensive studies of pulsar polarization, detailed observations of the recovery from period discontinuities and the discovery of the first radio pulsar in another galaxy. The papers in low frequency radio astronomy give the first high-resolution whole sky surveys at frequencies below 20 MHz, and an analysis which revealed the free electron distribution in the galactic plane subsequently confirmed by other measurements such as the dispersion of pulsar signals. The great majority of the work reported here has been carried out using national or shared facilities - for example the Australian National Radio Astronomy Observatory at Parkes, New South Wales, and facilities of the Deep Space Communications Network operated for NASA. Many of the equipment configurations were 'unusual' in the sense of being non-standard at the observatories. It is neither feasible nor sensible to operate someone else's telescope in such a manner on your own, and I have had very profitable collaboration not only with colleagues and students at the University of Tasmania but also with members of the CSIRO Division of Radiophysics (which Division operates the Parkes Observatory). Such collaboration has been a vital factor in getting the science done but it has led to joint authorship of many of the papers in this collection, and at times the ordering of authors on a paper has been influenced by more than scientific factors (including a scientific journal's \house style\"). I have therefore prefaced the thesis with a short review concentrating on my contributions to the material presented. Not all the publications which are submitted are covered by the review but rather the key papers and topics. The review is followed by a full list of the papers submitted together with further comments on my contributions to papers with several authors. The thesis concludes with the submitted papers grouped according to topic rather than in chronological order. All of the material presented here is original; I have submitted none of it for the Degree of Doctor of Science."