Square Kilometre Array Radio Telescope in Australia to cover 50 to 350 MHz

The Square Kilometre Array (SKA) is an international radio astronomy project with the object of scanning the cosmos from 50 Mhz to 15.4 GHz.

This project was originally conceived in 1991. The first 10 years were about developing the concepts and ideas. The second 10 was spent doing the technology development. And then the last decade was about detailed design, securing the sites, getting governments to agree to set up a treaty organisation (SKAO) and provide the funds to start.

There are two key sites. The SKA-mid array in South Africa covers 350 MHz to 15.4 GHz and it uses dish antennas. In this post, I'll focus on the SKA-low array in Western Australia which covers 50 MHz to 350 MHz.

The SKA-low array will be located at a remote site near Murchison in Western Australia. Bulldozers are expected to start working on the site in early 2023, with the completion date estimated as 2028. 

The array is described as follows... "a phased array of simple dipole antennas to cover the frequency range from 50 to 350 MHz. These will be grouped in 40 m diameter stations each containing 256 vertically oriented dual-polarisation dipole elements.". 

"Stations will be arranged with 75% located within a 2 km diameter core and the remaining stations situated on three spiral arms, extending out to a radius of 50 km."

While the array description is of 'simple dipole antennas', the 'Christmas Tree' antenna is actually a log-periodic antenna with two polarisation feeds. There seems to be a metallic grid underneath to maximise the gain upwards.

While the gain of each individual antenna is low... possibly in the region of 6dBd... it's the sheer number of antennas fed in phase with each other that gives the high gain and resolution.

The array will produce up to ~5 Tb/s (or ~ 700 GB/s) of measurement data, which is equivalent to downloading ~200 High-Definition movies in one second. This data will be transported via a dedicated fibre from the Murchison Radio-astronomy Observatory to the SKA-Low science processing centre located in Perth. 

As might be expected, all radio transmitters are banned from the area to maintain a low noise environment. The Murchison site is about 600kms to the north of the city of Perth and is very remote.

Videos... Sirio are probably better known to the radio community as the manufacturer of various types of CB antenna as well as some for the VHF amateur bands. Their antenna plant in Volta Mantovana (Italy) will produce 78,000 'Christmas tree' antennas which will go to Western Australia to form the low-frequency part of the SKA telescope.

1) The video is in Italian but YouTube does a good job of translating it...

2) This second video titled 'Making the SKA telescopes a reality: the next chapter' gives an overview of the SKA project.

It is expected that the Square Kilometre Array project will contribute to many areas of radio astronomy.

These include...
Signals emitted in the first few hundred million years after the Big Bang.
Trace the full history of hydrogen, the most abundant element in the Universe.
Detect hydrogen's presence even before great clouds of it collapsed to form the first stars.
Fast radio bursts which output the equivalent of an entire year's worth of energy from our Sun in just a fraction of a second.

Links...
1) For more information on the SKA project, go to https://www.skao.int/

Radio astronomers image sky at 144 MHz in more detail

I came across an interesting article today about how radio astronomers are in the process of plotting the radio sources of the northern sky in more detail at 144 MHz.

The problem up to now is that the ionosphere slightly distorts the signal at 144 MHz and that impacts the resolution of the radio image. A team of radio astronomers have now worked out a way to compensate for this distortion which allows resolution of radio sources at much greater detail. Some of these are shown above.

The paper was published in Nature Astronomy on the 27th of January 2022 and a preview can be seen HERE

Radio Astronomy from Cork in Ireland!!

OK...Not exactly Amateur Radio related but I can see it from my house! The piece below appeared in a local newspaper about a 32 metre dish which happens to be the largest in the country. Instead of leaving it to rust, the dish which is located just north of Midleton in Cork is now going to be utilised for Radio Astronomy.

"IT was destined for the scrapheap, but a rusted and outdated satellite dish will soon be transmitting sounds from the very edges of the known universe. Astronomers will upgrade the 32-metre dish with hi-tech detectors, transforming it into the country’s largest deep space radio telescope and enabling it to "listen" to cosmic signals coming from distant galaxies created soon after the Big Bang. It is hoped to be in operation by June 2011.


Details of the exciting partnership between Cork Institute of Technology (CIT) and the National Space Centre (NSC) Ltd will be announced this morning by Sean Sherlock TD, the Minister of State with responsibility for Research and Innovation. The telescope, located just outside Cork city, will allow astronomers to "listen" to radio waves coming from some of the most mysterious and oldest objects in the universe.


Because of its huge size, the telescope will be able to pick up signals from black holes, pulsars and quasars located billions of light years from Earth — almost at the edge of the observable universe. It will also be able to "image" most astronomical objects such as galaxies, nebulae and even radio emissions from planets.


The telescope will be linked to CIT’s Blackrock Castle Observatory in Cork city, and in turn made available to thousands of school children, making it one of the biggest in Europe used for education and outreach. IT’s head of research, Dr Niall Smith, said: "There is nothing else like it in the country. It’s a pretty special instrument."


The dish, at Elfordstown, near Midleton, was developed in the 1980s as part of a joint venture between the European and American communications industries. It entered service in 1984 with Telecom Éireann, carrying data, voice and television services between Europe and the US until the mid-1990s. But its 32-metre dish was considered too big for today’s commercial uses and it could simply have been left to rust.


This appeared in the printed version of the Irish Examiner Monday, May 09, 2011"

So a Radio Astronomy dish located 15 kms away...how cool is that! They'll be fine as long as they don't listen on 50 MHz ;o)