getting tours of radio telescopes is a great radio engineering experience. these “electronic hums” are of course a live detailed broadcast of everything everyone’s devices are processing (as well as radar, biosignals by hearsay, weather) https://www.space.com/square-kilometer-array-radio-quiet-electronics Electronics on world's largest radio telescope are more radio-quiet than a smartphone on the moon published 5 days ago Human-made electronic hums could limit the telescope's ability to peer into the deepest universe. The Square Kilometer Array Low frequency telescope in Australia will be able to detect the faintest radio signals from the most distant reaches of the universe. [1] (Image credit: SKAO) New electronic devices designed to power antennas of the world's largest radio telescope are so quiet that they'll cause less disturbance than a mobile phone on the moon. The new electronic devices, or SMART boxes, were developed for the Square Kilometer Array [2] (SKA) Low frequency telescope, a network of radio dishes currently under construction in Western Australia. Together with its mid-frequency counterpart, which is being built in South Africa, the SKA Low telescope will be the world's largest and most sensitive radio telescope once it comes online later this decade. [here was media my device did not render] SKA Low's 131,072 dipole antennas will be able to detect the faintest radio signals coming from the most distant reaches of the universe. But this exquisite sensitivity means that the array, located in a remote, barely inhabited area about 500 miles (800 kilometers) north of Perth, will be very susceptible to interference from human-made sources of radio waves. For example, a recent study[3] found that the telescope's antennas are so sensitive that they'll pick up even the soft hum emitted by electronics on board SpaceX's Starlink internet-beaming satellites, which orbit 342 miles (550 kilometers) above Earth. Human-made sources of radio waves could interfere with the observations and confuse astronomical research. The Square Kilometer Array Observatory's (SKAO) radio spectrum manager Federico di Vruno told Space.com in an earlier interview that this interference could, for example, impair the telescope's search for signs of extraterrestrial life[4]. To minimize disruptions, a radio-quiet zone surrounds the telescope, where the use of mobile phones and radio transmitters is strictly controlled. And, to make sure that the telescope's own electronics don't contribute to the problem, engineers at the International Centre for Radio Astronomy Research (ICRAR) at Curtin University in Perth developed special power and signal distribution devices that emit nearly no electromagnetic radiation. "It’s so radio-quiet at the observatory site that the biggest potential source of interference is the electronics like ours, due to the proximity to the antennas," Tom Booler, program lead for engineering and operations at ICRAR, said in an emailed statement. "That meant our project had to meet the strictest radio emission requirements across the entire Australian SKA site." In addition to being made from radio-quiet components, the devices are encased in special wrapping that prevents any electromagnetic radiation from escaping into the environment. When tested, the devices emitted less radiation than would reach the antennas from a mobile phone placed on the surface of the moon, Booler added. Construction of the giant radio telescope[5] began in December 2022 after more than 30 years of preparations. The two telescope sites in Australia and South Africa will have a combined collecting area of 1 square kilometer, as the name suggests, or 0.34 square miles. The site in Western Australia will listen to radio waves with the lowest frequencies, between 50 to 350 MHz. The South African array, which will consist of 197 50-foot-wide (15 meters) dish antennas, will focus on shorter wavelengths, between 350 MHz and 15.4 GHz Radio waves have much longer wavelengths than visible light, which enables them to penetrate through dust and debris. Sensitive radio telescopes such as SKAO allow astronomers to detect radio waves escaping from parts of the cosmos that are otherwise obscured and invisible to other types of telescopes. "The SKA telescopes will truly revolutionize our understanding of the universe," Catherine Cesarsky, the chair of the SKAO council, said in a statement last year. "They will allow us to study its evolution and some of its most mysterious phenomena in unprecedented detail, and that's really exciting for the scientific community." 1: https://cdn.mos.cms.futurecdn.net/SS69w5KaqtWjuYpoUEV8hg-1920-80.jpg.webp 2: https://www.space.com/square-kilometre-array-observatory-skao 3: https://www.space.com/starlink-electronics-hum-disturbs-radio-astronomy

https://www.aanda.org/component/article?access=doi&doi=10.1051/0004-6361/202346374 4: https://www.space.com/spacex-starlink-affects-search-for-life-radio-observat... 5: https://www.space.com/square-kilometer-array-observatory-construction-begins