Many thanks to SWLing Post contributor, James Jordan, who shares a link to this article in Wired magazine:
IF YOU TUNED into just the right shortwave radio frequency in the 1970s, you might hear a creepy computerized voice reading out a string of numbers. It was the Cold War, and the coded messages were rumored to be secret intelligence broadcasts from “number stations” located around the globe.
Photographer Lewis Bush is obsessed with these stations to “an almost irrational degree” and hunts them down in Shadows of the State, featuring 30 composite satellite images of alleged number stations from Germany to Australia. The series took two years and endless research. “It’s a difficult project to quantify in terms of man hours wasted on it,” he says.[…]
When Bush finds what he believes to be a station, he takes up to 50 close-up screen grabs and stitches them together in Photoshop to create one high-resolution image. He also listens to frequencies where broadcasts supposedly still happen on radio listening software, taking screen shots of the software’s spectrograms, graphics depicting the sound spectrum.
The final images try to visualize something largely intangible. No government has ever confirmed the existence of numbers stations, and Bush himself isn’t completely certain of their locations. No one can be sure what these scratchy codes really are. And that’s precisely what makes them so intriguing.