In its annual report on North Korea, press freedom watchdog Reporters Without Borders notes the resumption of jamming in 2007 of broadcasts beamed into North Korea. The organisation says:
Several foreign-based radio stations have increased their airtime, while newspapers available online, in particular Daily NK, have stepped up their coverage. But the regime responded to the challenge on 11 May by resuming jamming independent and dissident radios broadcasting to the people of North Korea: Free North Korea Radio, Voice of America, Open Radio for North Korea, Radio Free Asia and Radio Free Chosun. A manager at Open Radio for North Korea told Reporters Without Borders that this backward step could be linked to the opening of a railway line between North and South.
Jamming of short wave radios had noticeably eased after July 2006, since the authorities, hampered by a serious energy crisis, did not have the capacity to scramble broadcasts all day and on all frequencies.
(Source: Reporters Without Borders/R Netherlands Media Network Weblog)