During the recent pro-democracy anti-regime protests in Cuba, the Cuban government apparently began to jam amateur (ham) radio communications. Listen in the video below as it happens. IEEE Spectrum's Stephen Cass has the story:
Amateur radio operators in the United States found that suddenly parts of the popular 40-meter band were being swamped with grating signals. Florida operators reported the signals were loudest there, enough to make communication with hams in Cuba impossible. Other operators in South America, Africa, and Europe also reported hearing the signal, and triangulation software that anyone with a web browser can try placed the source of the signals as emanating from Cuba.
Cuba has a long history of interfering with broadcast signals, with several commercial radio stations in Florida allowed to operate at higher than normal power levels to combat jamming. But these new mystery signals appeared to be intentionally targeting amateur radio transmissions. A few hours after the protest broke out on the 11th, ham Alex Valladares (W7HU) says he was speaking with a Cuban operator on 7.130 megahertz in the 40-meter band, when their conversation was suddenly overwhelmed with interference. "We moved to 7170, and they jam the frequency there," he says. Valladares gave up for the night, but the following morning, he says, "I realize that they didn't turn off those jammers. [Then] we went to 140 the next day and they put jamming in there."
Valladres explains he escaped from Cuba to the United States in a raft in 2005. Like many hams in the large Cuban-American community in Florida, he frequently talks with operators in Cuba, and now he says the government there is "jamming the signal to prevent the Cuban people who listen to us and to prevent them from talking between them[selves]."
"Cuba Jamming Ham Radio? Listen For Yourself" (IEEE Spectrum)