Wired Magazine run an interesting news article entitled "The Great Brazilian Sat-Hack Crackdown"
Photo caption: Brazilian satellite hackers use high-performance
antennas and homebrew gear to turn U.S. Navy satellites into
their personal CB radios
antennas and homebrew gear to turn U.S. Navy satellites into
their personal CB radios
The article referred to "Much of this country's geography is remote, and beyond the reach of cellphone coverage, making American satellites an ideal, if illegal, communications option. The problem goes back more than a decade, to the mid-1990s, when Brazilian radio technicians discovered they could jump on the UHF frequencies dedicated to satellites in the Navy's Fleet Satellite Communication system, or FLTSATCOM. They've been at it ever since."
Bearing in mind the above is a recent event, it's surprising nothing had been done about eavesdrop and communications signal hijack much earlier. Although the above states "mid-1990s", a scanner hobbyist in 1991 allegedly reported hearing (whilst scanning) the start of the air attack on Baghdad from US aircraft on the FLTSATCOM downlinks.
The Wired article reports "Rogue loggers in the Amazon use the satellites to transmit coded warnings when authorities threaten to close in. Drug dealers and organized criminal factions use them to coordinate operations."
The crackdown, called "Operation Satellite," was Brazil's first large-scale enforcement against the problem. Police followed coordinates provided by the U.S. Department of Defense and confirmed by Anatel, Brazil's FCC. Among those charged were university professors, electricians, truckers and farmers, the police say. The suspects face up to four years and jail, but are more likely to be fined if convicted.
http://www.wired.com/politics/security/news/2009/04/fleetcom