SETI FAQ

At what distance from Earth can radio and TV signals be detected, given current technology? Not very far beyond Pluto's orbit, really.

"Detection of broadband signals from Earth such as AM radio,
FM radio, and television picture and sound would be
extremely difficult even at a fraction of a light-year
distant from the Sun. For example, a TV picture having 5
MHz of bandwidth and 5 MWatts of power could not be detected
beyond the solar system even with a radio telescope with 100
times the sensitivity of the 305 meter diameter Arecibo
telescope."