Sean Gallagher at Ars Technica revisits the still-unsolved Nov. 22, 1987 pirate television hijacking of the signal of two Chicago television stations. A man in a Max Headroom mask broadcast a taped message interrupting a prime-time news broadcast on Chicago's WGN, and a broadcast of "Dr. Who" on the Chicago public television station WTTW. Whoever was responsible for the most famous pirate broadcast in United States history has never been identified by authorities. The pirate overpowered the signals sent by the television studios to a transmitter and antenna atop the John Hancock building in Chicago, replacing the scheduled programming with their own. WGN engineers were able to to switch frequencies on the studio-to-transmitter link to quickly take back the broadcast signal. The WTTW takeover lasted 90 seconds, with the audio audible. Gallagher reports a similar signal hijacking took place in England in 1977. An ITV Southern Television broadcast showed an alien representative of an "Intergalactic Association" with the message, "All your weapons of evil must be removed… You have but a short time to learn to live together in peace." There are also reports that in 1986, supporters of the Polish labor movement Solidarność took over state television stations with "printed anti-government messages," and other reports of state television stations in the Soviet Union frequently being taken over by pirate transmissions around the same time. More recently, an HDTV broadcast of a Washington D.C. ABC affiliate was taken over in 2007, with a morning news broadcast replaced by a black and white photo of a man and woman. Radio station signals get hijacked more often. Earlier this year several U.S. radio stations lost their signals, with a profane song about the current president replacing regularly scheduled programming.