> The Arecibo Observatory and FAST could each detect the TV carrier wave leakage out to a distance of about sixteen lightyears. That’s a little bit further away

> The Arecibo Observatory and FAST could each detect the TV carrier wave leakage out to a distance of about sixteen lightyears. That’s a little bit further away than Tau Ceti is. https://www.forbes.com/sites/quora/2017/01/27/how-far-into-space-can-radio-telescopes-hear/#1ad0fac25de7#1ad0fac25de7 https://www.forbes.com/sites/quora/2017/01/27/how-far-into-s... That's for detecting a TV broadcast. But how far away could one Arecibo observatory detect another Arecibo? > The answer is, that except for obscuration and dust in certain places, it could be anywhere in the galaxy and we would pick up the signals. That means at least one hundred billion stars that you can listen to for signs of extraterrestrial intelligence. https://www.rollingstone.com/culture/culture-news/carl-sagan-life-on-other-planets-162285/ https://www.rollingstone.com/culture/culture-news/carl-sagan...