JG0LD writes "Students at a tiny Appalachian public school can't use Wi-Fi because any such network can throw the radio equivalent of a monkey wrench into a gigantic super-sensitive radio telescope just up the road. GBT's extraordinary sensitivity means that it's very susceptible to human-generated radio interference, according to site interference protection engineer Carla Beaudet. 'If there was no dirt between us and the transmitter, a typical access point ... would have to be on the order of 1,000,000 km [more than 620,000 miles, or about two and a half times the distance from the Earth to the Moon] distant to not interfere. Fortunately, we have mountains around us which provide lots of attenuation, so we're not seeing everything from everywhere,' she said. A standard Wi-Fi access point would wipe out a significant range of usable frequencies for the observatory. 'It simply ruins the spectrum for observations from 2400-2483.5MHz and from 5725-5875MHz for observational purposes,' wrote Beaudet."