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The Australia Telescope National Facility Colloquium
14:00-15:00 Tue 22 Feb 2011

ATNF Marsfield Lecture Theatre

Dr Andrew ('Andy') Kulessa

(DSTO Electronic Warfare and Radar Division)


Ever wondered how the weather impacts on the propagation of terrestrial radiowaves? Why 50cm broadcast transmitters can interfere with radioastronomical observations for long periods of time, despite being located hundreds of kilometres away and way beyond the local horizon? Whether such ‘ducting’ events can be reliably predicted?. These questions are of wider interest, for scientists, engineers and technologists designing wireless communication services, managing spectrum & RFI and conducting radio-astronomical observations – eg. ISM researchers may find considerable analytical synergies!

Dr Andrew (‘Andy’) Kulessa, a radiometeorologist with the DSTO’s Electronic Warfare and Radar Division, will in this talk provide an overview of tropospheric radio propagation, in particular the phenomenon known as ‘ducting’. Andy will cover the basic concepts of atmospheric refractivity and describe some of the atmospheric processes that can cause ducting of signals. The concepts of radio-holes and signal “leakage” from ducts will also be discussed. Examples of non-standard signal coverage will be given from some of his extensive radio measurement campaigns, as well as theoretical predictions of signal coverage using mesoscale modelling techniques.

BIO: Andy was born in Newcastle, Australia and received his scientific training at universities within Australia and the United Kingdom. His research interests include the characterisation of clear-air tropospheric propagation phenomena, measurement and modelling of micro and meso - scale meteorological phenomena and how these atmospheric phenomena affect communications and Electronic Warfare systems. He has also been involved in the design and development of instrumentation to measure microwave ducting. Other research activities include the design, development and testing of novel electronic support measures systems. Andy is a member of various scientific bodies and technical committees.

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Erik Lensson

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