This is unfortunately not true for radio astronomy, the receivers are very sensitive, and will show interference from even a simple LCD screen within a mile. At

This is unfortunately not true for radio astronomy, the receivers are very sensitive, and will show interference from even a simple LCD screen within a mile. At frequencies below 1 GHz, the VLA often has to throw away more than half of the data due to interference. Most observations happen outside of the protected bands, nature uses the whole spectrum, although the absolute most important bands are protected, like the 1420 MHz hydrogen line. For comparison, if you put a cell phone on the surface of the moon, it would be the brighter than the brightest natural source at 2 GHz. FM bands are wiped out, but some experiments where it is really important (the epoch of reionization) are put specifically in Western Australia or South Africa where it's wasteland and they protect the sites from interference.