Newsletter for the Rotary Club of Greater Geraldton - Issue No.: 782 Issue Date: 29 Apr, 2024

Introduced by a rather tongue tied Peter Sukiennik, Christoph Brem is a radio-frequency Engineer with a broad background in signalling and receiver systems and global HF communication networks. He was born in Switzerland, moved to Narrari NSW and transferred to Geraldton in February this year to work with the commissioning of the SKA project. Like your club photographer, his hobby is collecting photons!

The CSIRO Astronomy and Space Science Australia Telescope National Facility extends right around Australia, Parkes of course was made famous by the movie “The Dish” but is in fact Tidbinbillla that operates closely with NASA.

How does a radio telescope work? The antenna (“dish”) collects the electromagnetic energy and reflects it onto the central receiver, where it is converted into digital data into a signal processing correlator! Now did you get that?

Christoph went on to point out the similarity between the modern Smart Phone and radio telescopes. A radio receiver converts signals from a radio antenna to a usable form, just what our phones do! The ones in the telescopes capture the signals and amplify them. By blending XRAY, UV, optical and infrared and other electromagnetic signals, a complete image of a galaxy can be obtained. But the signals are weak, similar to picking up a signal from a mobile phone on the moon!

Why build these structures in the outback? The answer is the need for absolute radio quiet to be able to pick up extremely weak signals and not have them corrupted by background radio clutter. The huge Murchison Shire, at 41.000 square kilometres, with no towns and a population of 120 is ideal, the best spot in the world! Indeed, legislation has been passed to ensure a 70km area of complete radio quiet. The Murchison Radio Observatory has required 30km of roads and an emergency airstrip to be built, together with 7776 fibres to connect the 36 antennas and the control building. This building is a dual faraday cage that reduces any extraneous signal by 100 billion billion!!

The Australian Square Kilometre Array Pathfinder has 36 antennas which will give a huge field of view of the sky. Data streams in form the telescopes at 72 trillion bits per second and the ASKAP correlator combines the data mathematically to compress it by 20 thousand times. An example of the power of this system: It took the ATCA array 12000 hours to obtain the Centaurus A image, 15 million light years away. The ASKAP took 10 minutes!

Christoph was thanked by PP Tim Duggan, who like the rest of us, was blown away by the presentation!