MSc Dissertation: Sydney Dunn


Adobe-PDF-downloadDunn, Sydney Bobby. A Study of the SA SKA RFI Measurement Systems. MSc Dissertation. Department of Electrical Engineering, University of Cape Town, 2008.



The Square Kilometre Array (SKA) is an ambitious multi-billion rands project to build the worlds’s largest and most sensitive radio astronomy telescope. The telescope will have a collection area of 1 million square metres and will be able to look at a larger portion of the sky than current telescopes. The sensitivity of this telescope is of such a nature that isolation of this instrument from the negative effects of man-made noise is paramount. As such a campaign to measure the levels of electromagnetic radiation at the prospective sites had to be conducted. In response to this, the South African (SA) SKA team developed the RFI Measurement System 2 to perform these measurements.

This dissertation documents the findings of a study of the functionality of RFI Measurement System 2 that was conducted by the author. An in depth study of MEMO 37 (RFI Measurement Protocol) was employed first. After which, an exhaustive audit of all the equipment used and a thorough analysis of the method of data collection and processing was conducted. A sample of raw uncalibrated, MODE 1 field measurement data was scrutinized. The data chosen was for RF signals in the 70 – 150 MHz frequency range and following similar data processing procedures as that of the SA SKA team, the plots of Spectral Flux Density versus Frequency were generated in the laboratory using MATLAB.

It was found that for the frequency range 80 MHz to 150 MHz, these graphs closely matched that of the SA SKA team and that for this bandwidth, both the SA SKA graph and that replicated by the author were within their tolerance limits. A relatively strong correlation coefficient of 0.4430 was observed for the maximum values graph. The range 70 MHz to 80 MHz lies outside the operational ability of the antennas as prescribed by the manufacturers and for this reason some differences between the work of the SA SKA team and that of my work was observed for this range.



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