china jamming

WORLDWIDE DX CLUB
Top News

compiled by Wolfgang Büschel, Germany
April 24th, 2009 (BC-DX #909)

CHINA   Program content of the "Firedrake" network jammers changed last
weekend, is rather a CNR/CRI satellite feed channel re-shuffle, see mail
below by Mark Fahey.

Puzzle -- Firedrake on 15635 kHz at 1300-1400 UT, against UNID service ?
Maybe another Xi Wang Zhi Sheng SOH-Sound of Hope service from Taiwan?
(wb, wwdxc BC-DX TopNews Apr 19)

Firedrake, 1514-1535, April 16. Scanned every 5 kHz. from 7000 to 19000,
but did not find any noticeable Firedrake. Are they really gone?
(Ron Howard-CA-USA, dxld Apr 19)

China jamming service now changed the format, continous playing of dragon
music via the JAMMING NETWORK stopped now.

Few and between advertising talk [Howard and Hauser said China National
radio 1st program relay] and music jammer but rather lyric Chinese love
songs played now, even Elton John sung in between. Some 3 to 4 very fast
echos of few un-synchronized transmitters appeared as 'new sound'. Modern
Chinese and international smooth love songs in between.

Is full in action like in past weekend log, - frequ against txions in
Mandarin, Cantonese, Tibetan, Uighur, Nepali etc. noted here in Europe on
45 shortwave channels:

7260 1700-2100 IBB TIN                7565 1600-1700 IBB UDO
9350 0100-0200 1600-1700 IBB UDO      9355 1700-2100 IBB SAI
9370 1500-1600 IBB TJK                9385 2100-2200 IBB TIN
9455 1500-2200 IBB SAI                9565 1600-1700 IBB Tinang
9845 1200-1500, 2200-2300 IBB SAI Tinang
9985 1300-1400 IBB SAI               11540 1500-1900 IBB TIN, SAI
11550 1500-1600 IBB KWT               11585 1500-1600 IBB TIN
11590 1200-1400 IBB KWT               11605 1200-1400 IBB TIN
11615 1400-1500 IBB SAI               11625 1500-1600 IBB TIN
11665 1100-1700 TWN Internat          11740 2000-2200 IBB TIN
11785 1900-2400 IBB TIN               11785 1100-1400 IBB UDO
11805 1230-1500 IBB UDO, Tinang, TIN
11825 0900-1300 IBB Tinang            11965 0900-1100 IBB UDO
11975 1400-1500 IBB KWT               11990 1100-1500 IBB TIN, NVS
12025 1500-1700 IBB SAI               12040 1000-1500 IBB UDO, Tinang
12140 1230-1500 IBB TIN -Burmese? different from Myanmar?
13675 1500-1700 IBB TIN               13740 0700-1000 IBB UDO
13760 0300-0700 IBB SAI               13830 1100-1400 IBB TJK
15250 0700-1100 IBB Tinang            15265  0300-0600 IBB UDO, echo
15285 1300-1530 BBC SNG               15412 1330-1400 VoTibet TJK
15490 0300-0600 IBB IRA, echo         15495 1500-1600 IBB TIN
15535 0600-0700 UNID, maybe 24 hrs service jammer.
15840*1000-1200 UNID, SoH TWN ?       17560 1330-1400 VoTibet MDG
17615 0300-0700 IBB TIN, echo         17635 0300-0700 IBB Irkutsk-RUS echo
17735 0400-0600 IBB UDO, echo         17775 0700-1000 IBB TIN
17855 0700-1100 IBB Tinang            17800 0300-0700 IBB SAI

All new multi ECHO "programme" format, except real Firedrake dragon music
marked by *.

Also transmissions of BBC London Mandarin on 15285, Uzbek, Kyrghyz; AIR
Delhi Mandarin Tibetan, Nepali; Taiwan domestic and international
broadcasts 11665 and 15270, - are subject of heavy jamming.
(wb, wwdxc BC-DX TopNews Apr 19-22)

Jamming from China to PEAK soon!
This year marks the 20th Anniversary of the Tiananmen Square crackdown and
the authorities in China are getting ready. The State Administration of
Film, Radio and Television (SAFRT) has already sent out a memo to CCTV
(Central China Television), CNR (China National Radio) and CRI (China
Radio International) as well as the thousands of local provincial radio
stations to inform them about the "special measures" that will be in place
from May 18th to July 31, 2009.

Jamming during this period will also be stepped up. So if you tune to the
SW dial starting on or around that date, the very popular FIREDRAKE [not
at present, see above, wb] will be heard just about everywhere and
anywhere in the world. As many of you might know, Firedrake does not just
interfere with signals beamed to China, but also with signals beamed to
other regions.
(Keith Perron-TWN, dxld Apr 22)

"Programme" content of the "Firedrake jamming network" changed last
weekend, all acc to observations of Ron Howard-CA-USA in dxld.

Only FOUR REAL Firedrake dragon music jammers noted here in Europe,
remained on air since Apr 19:

15150* approx. 0400-0600
15635* 1300-1400
15820* approx. 0400-0600
15840* 1000-1200

Formerly also on 13970, and 15900 kHz against Xi Wang Zhi Sheng SOH-Sound
of Hope service from Taiwan.

Somebody in the Pazifik, Far East, or South Asia should monitor the
shortwave bands in the 0000-0500 UT portion.

"Firedrake" jamming service now changed the format, continous playing of
dragon music stopped now. Few and between advertising talk [Howard and
Hauser said China National radio 1st program relay] and music jammer but
rather lyric Chinese love songs played now, even Elton John sung in
between. Some 3 to 4 very fast echos of few transmitters appeared as 'new
sound'. Modern Chinese and international smooth love songs in between.

Is full in action like in past weekend log, - frequencies against txions
in Mandarin, Cantonese, Tibetan, Uighur, Nepali etc., noted here in Europe
on 48 shortwave channels, like on additional:

15265  0300-0600 IBB UDO, echo     15490  0300-0600 IBB IRA, echo
17615  0300-0700 IBB TIN, echo     17635  0300-0700 IBB Irkutsk-RUS echo
17735  0400-0600 IBB UDO, echo

Who is Keith Perron, from Taiwan ?
Is a real character or an outlet of a western intelligence service?
(wb, wwdxc BC-DX TopNews Apr 22)

Re: new echo sound recording.
Thanks for the audio. You heard a typical CNR-1 echo jamming (operating
more than one jamming transmitter and out of sync, causing echo). It is
non-Firedrake jamming, i.e., not non-stop Chinese music jamming. There
have been many of these echo jammers used on many frequencies for some
time now. The attachment is a recording from March 9, 2009, at 1308 of
another typical CNR-1 echo jamming, in this case supposedly against Ming
Hui Radio on 6030. Heard // 5030, a standard non-jamming CNR-1 station.
Thanks again for sharing this information!
(Ron Howard-CA-USA, wwdxc BC-DX TopNews Apr 22)

Real Firedrake observations:
April 19 at 1312 on 9000, and at 1316 just barely audible on 8400. April
20 at 1227, good on both 9000 and 8400; at 1325 gone from 9000 but still
on 8400; ditto at 1346 and 1424 rechex. Firedrake, April 21 at 1325: on
8400 and weaker 9000 kHz.
(Glenn Hauser-OK-USA, dxld Apr 21)

Observed 0215-0245, April 23:
Firedrake (non-stop Chinese music jamming): 17300 and 18320, both // and
against SOH.

CNR-1 (assumed) distinctive echo jamming, all parallel: 11830 and 11925
(both against VOA), 17730 (against R. Free Asia) and 17765 (against VOA).

Assume the echo programming was CNR-1, due to the absence of a known non-
jamming CNR-1 to check these with during this time period.
(Ron Howard-CA-USA, dxld Apr 23)

I just now drove my dish across to Chinasat 6 to see if there had been
changes to the Firedrake transmitter feed. And I can report yes there has!

The circuit that carried Firedrake is right at the moment carrying what
sounds like a drama with some intervals of Mongolian Throat Singing, just
as I started typing they have gone to commercials and now at the top of
the hour the feed has gone silent. I will stick with this channel to night
and see if I can find some parallels on HF. It maybe that they have
reorganized some circuits, and what I am hearing is not feeding the
jammers - anyway within a day or so I should have it worked out.

[later] Our friends in Beijing seem to have done a major reorganization of
their satellite transmitter feed circuits on Chiniasat 6B. Where Firedrake
use to be it now seems to be a CRI feed, Firedrake now has it's own stereo
circuit labeled "ZY18 Stereo" - the program still seems to be in mono
though.

What is new is that now the CNR (China National Radio - Domestic) and CRI
(China Radio International) circuits are combined in same group of
channels. Previously I had to access one satellite for the CNR feeds
(Chinasat 6B) and another (Intelsat 8) for the CRI feeds.

At the moment on Chinasat 6B there are 50 separate stereo program
transmitter feed channels operating. CNR circuits are named "ZY xx" and
CRI are named "GJ xx".

Perhaps one or more of the more sleepy of the Firedrake jammer transmitter
sites are yet to catch up with the changes and at time "accidentally"
putting the old Firedrake circuit to air instead of the new Firedrake feed
of ZY18 Stereo.

Broadcast Jamming Continues in Post Cold-War World

Broadcast Jamming Continues in Post Cold-War World
By Gary Thomas Washington 13 October 2005

During the so-called Cold War, totalitarian regimes sought to block radio or TV broadcasts, except the ones they controlled. The Cold War is over, but those jamming efforts continue in some parts of the world. VOA Correspondent Gary Thomas reports from Washington on the 21st century battle of the airwaves.

Authoritarian governments still try to silence criticism and unfavorable news coverage in their countries by the age-old expedient of throwing critics in jail and shutting down their publications. But what does today's autocrat do about broadcasts being beamed into his country from sources outside his reach?

Simple. He jams them.

A longtime researcher on international broadcasting at the Voice of America, Kim Elliott, says the methods of jamming radio broadcasts are still much the same as they have been, even with new technologies.

"It is simply a matter of putting a noxious signal on the same frequency as the broadcaster that is trying to get into the country. And it was that way during World War II, it was that way during the Cold War, and it is still that way. If you tune across your short-wave radio, you will hear a raucous noise on one frequency, and you will hear the hapless international radio broadcaster in the background trying to get into the country," he said.

The result is rather like being in a crowded room watching a sporting event, with the cheering so loud that it is almost impossible to hear the person sitting right next to you.

Free speech advocates have always condemned jamming as an attempt to cut off the uninterrupted flow of information. Kenneth Tomlinson, the chairman of the U.S. government's Broadcasting Board of Governors that oversees VOA, Radio Free Asia, and other government-sponsored broadcast entities, has said it is illegal, and interferes with the free and open flow of international transmissions.

Experts say that, ironically, newer broadcast technologies, such as television, are actually easier to jam than old-fashioned short-wave radio, simply because radio can air on so many different frequencies at once.

Broadcast researcher Kim Elliott says jamming TV signals, especially from satellites, is relatively simple.

"Of all the media available to international broadcasting, short-wave is the most difficult to interdict. And that is because of the physics of transmission at short-wave frequencies," he said. "Signals from more distant transmitters come through better than signals from transmitters closer up. Television transmissions travel much shorter distances, and so those are much easier to jam. Or, if they are from a satellite, they are easy to jam because it only requires a few watts [of power]. And it does not have that kind of immunity [from jamming] that short-wave has."

Asia specialist Vincent Brossel, with the French media research group Reporters Without Borders, says radio still remains the main source of information for many people around the world.

"The radio is something like the most democratized and the most popular media in the world, due to the fact that many people cannot read, or do not have any access to Internet," he said. "The only way to touch millions, or billions of people around the world is radio."

Analysts say this is why China has become the biggest practitioner of international radio jamming in the post-Cold War world.

Mr. Brossel says Western firms, such as the French firm Thales', have sold broadcast equipment to China that also can be used for jamming.

"What is very interesting is that some Western companies are selling technology to the Chinese, and Chinese are selling technology for jamming to some Third World countries," he said. "So, it means that, just for business reasons, foreign companies like Thales' are helping the Chinese government to prevent millions, or billions of listeners from getting some free and independent radio programs."

Thales' officials have declined to comment on the company's sales. An American firm, Continental Electronics, also has sold transmission equipment to China, and to VOA, Radio Free Asia, and Taiwan, as well.

Experts say the term "jamming equipment" is really a misnomer, since a transmitter is something of a two-edged sword that can not only be used to broadcast, but can be easily converted to jam broadcasts.

Although Iran's theocratic government officially bans satellite television and has jammed foreign broadcasts, including those of exile Persian-language stations, the jamming has been sporadic, and is usually conducted during elections and other political events. Azadeh Moaveni, an Iranian-American journalist, who has reported from Iran, says the reality is different than official policy.

"Satellite television is technically banned," she said. "It is implicitly tolerated. And you could, I think, say comfortably that the majority of the country has access to satellite news."

Sometimes political jamming is tried as well.

Eutelsat, a European satellite operator, earlier this said it would not renew its contract to carry the signal of a new language broadcast outlet called New Tang Dynasty TV, or NTDTV Its links to the Falun Gong group, which is banned in China, earned it official Chinese displeasure. Mr. Brossel of Reporters Without Borders said Eutelsat was under what he called "tremendous pressure" from China to cancel the NTDTV contract. But last month Eutelsat agreed to renew it.

Pentagon Jams Web, Radio Links of Taliban

By YOCHI J. DREAZEN and SIOBHAN GORMAN

WASHINGTON -- The Obama administration is starting a broad effort in Pakistan and Afghanistan to prevent the Taliban from using radio stations and Web sites to intimidate civilians and plan attacks, according to senior U.S. officials.

Associated Press

A U.S. soldier patrols Afghanistan's Korengal Valley. The U.S. is adding operations involving radio and the Web to its efforts against the Taliban.

As part of the classified effort, American military and intelligence personnel are working to jam the unlicensed radio stations in Pakistan's lawless regions on the Afghanistan border that Taliban fighters use to broadcast threats and decrees.

U.S. personnel are also trying to block the Pakistani chat rooms and Web sites that are part of the country's burgeoning extremist underground. The Web sites frequently contain videos of attacks and inflammatory religious material that attempts to justify acts of violence.

The push takes the administration deeper into "psychological operations," which attempt to influence how people see the U.S., its allies and its enemies. Officials involved with the new program argue that psychological operations are a necessary part of reversing the deterioration of stability in both Afghanistan and Pakistan.

The Taliban and other armed groups have carried out a wave of attacks in the two countries. U.S. officials believe the Taliban enjoy an advantage by being able to freely communicate threats and decrees.

In Pakistan, Taliban leaders use unlicensed FM stations to recite the names of local Pakistani government officials, police officers and other figures who have been marked for death by the group. Hundreds of people named in the broadcasts have later been killed, according to U.S. and Pakistani officials.

"The Taliban aren't just winning the information war -- we're not even putting up that much of a fight," said a senior U.S. official in Afghanistan. "We need to make it harder for them to keep telling the population that they're in control and can strike at any time."

The new efforts were described by an array of U.S. officials, several with firsthand knowledge of the technologies and tactics used to block the radio stations and Web sites. The Pentagon, the Joint Chiefs of Staff and the Central Intelligence Agency declined to comment.

Psychological operations have long been a part of war, famously in World War II when "Tokyo Rose" broadcast English-language propaganda to Allied troops. More recently, some militaries have used high-tech methods. During the December-January war in Gaza, Israeli forces sent cellphone text messages to alert Palestinian civilians to impending strikes and encourage them to turn against the militant group Hamas.

The Obama administration's recently released strategy for Afghanistan and Pakistan calls for sending 4,000 U.S. military trainers to Afghanistan and sharply expanding economic aid to Pakistan. The U.S. may also provide radio-jamming equipment to the Pakistani government, according to officials familiar with the plans.

Getty Images

U.S. Army soldiers from 1st Infantry Division set up a ladder by a watch tower at an operation post in Nishagam, Afghanistan's eastern Kunar province.

The new push reflects the influence of Gen. David Petraeus, who runs the military's Central Command and has long been a major proponent of using psychological operations to reduce popular support for armed Islamist groups.

Another supporter, Richard Holbrooke, the administration's special envoy for Pakistan and Afghanistan, publicly alluded to the new program late last month. He told reporters there were 150 illegal FM radio stations in Pakistan's Swat Valley, which allowed militants to go "around every night broadcasting the names of people they're going to behead or they've beheaded."

Mr. Holbrooke likened the Taliban radio stations to Rwanda's Radio Mille Collines, a virulently sectarian broadcaster widely believed to have helped fuel the Rwandan genocide. The U.S. considered jamming the station in the 1990s, but ultimately chose not to.

"Nothing has been done so far" about impeding the Taliban communications, Mr. Holbrooke said. "We have identified the information issue ... as a major, major gap to be filled."

Psychological operations can be controversial. In Iraq, the Pentagon at one point ran a program that paid Iraqi journalists to run articles and opinion pieces supportive of U.S. war aims and the Iraqi central government. Critics called it government-funded propaganda, while the Bush administration defended the effort.

Henry A. Crumpton, a former State Department counterterrorism chief who led the CIA's Afghanistan campaign in 2001 and 2002, warned against relying too heavily on high-tech solutions such as disrupting militant radio broadcasts. "Those can be very effective, but they're -- underscore -- short-term tactics," he said.

Still, many military officials believe that stabilizing Afghanistan and Pakistan requires gradually diminishing the Taliban's public standing while simultaneously building popular support for more moderate local political and religious institutions allied with the U.S.

"It's not an issue of trying to persuade your average Pakistani farmer to love the U.S.," a U.S. official said. "The idea, frankly, is to muddy the water a bit."

As part of this push, the U.S. has started U.S.-funded radio stations in many rural parts of Afghanistan. In one example, Army Special Forces teams in eastern Paktia, a restive Afghan province that abuts the Pakistani frontier, put on air a radio station late last year called "the Voice of Chamkani," referring to the village where the U.S. base is located, and distributed hundreds of radio receivers.

According to an account in the current issue of "Special Warfare Magazine," an Army publication on special operations, the U.S.-run radio station has worked to build support for the Afghan national government by highlighting local development projects that were approved by Kabul.

Write to Yochi J. Dreazen at yochi.dreazen@wsj.com and Siobhan Gorman at siobhan.gorman@wsj.com

Chinese advisor calls for improved broadcast coverage in border areas

Chinese advisor calls for improved broadcast coverage in border areas

March 9th, 2009 - 13:31 UTC by Andy Sennitt

Text of report in English by official Chinese news agency Xinhua (New China News Agency)

BEIJING, March 9 (Xinhua) - A Chinese political adviser has urged the government to improve TV and radio coverage in border areas to counteract infiltration by hostile foreign forces and protect national political and cultural security.

“Border areas lived by minor ethnic groups still face a grave situation in counteracting infiltration through TV and radio broadcasting,” said Ma Qingsheng, member of the 11th National Committee of the Chinese People’s Political Consultative Conference (CPPCC), at the annual session the political advisory body Monday in Beijing.

“Hostile and secessionist forces from overseas have been changing their tactics in infiltrating the border areas lived by minor ethnic groups, by increasing the power of projectors, the hours of broadcasting, and changing the venues of frequencies of broadcasting constantly,” said Ma, vice director of the Committee of Ethnic and Religious Affairs of the CPPCC National Committee.

According to him, among border villages with 20 households each, 23,000 are yet to be covered by TV and radio programmes. In the border areas of Yunnan province alone, 3.5 million people have no access to radio broadcasts, while three million people have no access to TV programmes.

Improving TV and radio coverage in the border areas is utterly necessary to raise awareness of government policy, prevent the infiltration of hostile foreign forces, consolidate ethnic unity, safeguard stability in the border areas, and enrich the cultural life of minor ethnic peoples, said Ma.

He urged the government to build more powerful projectors and strengthening the jamming of hostile foreign radios. The government must increase its financial support to radio and TV services in border areas and encourage the production of programmes in the languages of minor ethnic groups, he said.

(Source: Xinhua news agency, Beijing, in English 1108 gmt 9 Mar 09 via BBC Monitoring)

Andy Sennitt comments: The phrase “strengthening the jamming of hostile foreign radios” is interesting. It’s widely known that China has a considerable radio jamming operation, but it’s rare to see that openly admitted by an official news agency.

SLBC jamming FM broadcast prompts BBC to suspend partnership

[TamilNet, Monday, 09 February 2009, 23:21 GMT]
Sri Lankan state run SLBC, which airs BBC World Service programmes in FM, has deliberately jammed BBC Tamil 17 times and BBC Sinhala 8 times, between 27 November and early January 2009, according to a statement by the BBC World Service Press Office Monday. The BBC said it was suspending the programming agreement with the SLBC from Tuesday.

Full text of the statement issued by the BBC World Service Press Office follows:

BBC World Service is suspending its FM programming to the Sri Lankan national broadcaster SLBC from Tuesday 10 February due to deliberate interference of its broadcasts by the Sri Lankan network.

BBC programmes and individual news reports in the English, Sinhala and Tamil languages have been blocked by SLBC and have not been broadcast to listeners in Sri Lanka.

The BBC noted 17 instances of interference to BBC Tamil and eight similar instances to BBC Sinhala broadcasts between 27 November 2008 and early January 2009. Sometimes whole current affairs segments of BBC programming were not broadcast on SLBC.

The BBC expressed its concern directly to SLBC Chairman Hudson Samarasinghe in a series of letters and meetings throughout December and early January.

The BBC made it clear to SLBC that such interference and blocking meant that BBC programming was being editorially compromised by SLBC's actions and this was contrary to the BBC's contractual agreement with SLBC.

Despite the warnings, last week there were several further instances of interference to BBC programming in all three languages being broadcast on SLBC. There have been three instances of interference on BBC Tamil output, one on BBC Sinhala and two instances on the English language programming in the past 10 days.

BBC World Service Director Nigel Chapman says: "We are dismayed that the BBC's programmes in the English, Sinhala and Tamil languages have been interrupted on the SLBC network. We are equally disappointed to see that our programmes continue to be interfered with even after our representations.

"We have no choice but to suspend broadcasts until such time as SLBC can guarantee our programming is transmitted without interference," he says.

"In order to cover news events in the most comprehensive and balanced way for our audiences, the BBC adheres to specific editorial values that include impartiality, editorial independence and seeking a relevant range of views on any topic. In this way we can meet our audiences' high expectations and maintain our reputation as the world's most trusted international broadcaster."

He said: "The BBC has had a very cordial and effective partnership with the SLBC since 1998 – part of a strong relationship with listeners in that country that goes back to the 1940s. We are keen to keep this relationship going provided that SLBC adheres to the agreements we have with it. But at the heart of these agreements is the guarantee that our programmes in English, Sinhala, and Tamil are broadcast uninterrupted. If this can not be guaranteed we can not continue our relationship.

"We are prepared to have further discussions to resolve this issue and will investigate any specific detailed complaint SLBC may have about BBC output. So far, no specific complaint has been raised."

The BBC's services in all three languages remain in Sri Lanka via short wave; on bbc.com/news, bbcsinhala.com and bbctamil.com via the internet; and news bulletins in English are available via the Sri Lankan commercial broadcaster MBC.

Monday, December 29, 2008
RADIO JAMMING IN KOREA

Radio jamming on the Korean Peninsula makes the border region one of the world's busiest places for radio signals. MW jamming is dominant in the Korean Metropolitan area including Seoul and the DMZ (the border area between South and North Korea). South Korea jams broadcasts from North Korea, but does not jam broadcasts from other countries. However North Korea jams both South Korean broadcasts and foreign shortwave broadcast services which it believes to be against the North Korean regime. These include the Korean-language service of the Voice of America (VOA), Free North Korea Radio (which originates from US transmitters in Guam), and several other services and broadcasts.

Radio jamming in South Korea

The South Korean government constantly jams most radio broadcasts from North Korea on medium-wave. According to the National Security Law in South Korea, it is illegal to tune into or publish frequencies of North Korean broadcasts. Despite the fact, one cannot be easily punished for just listening to those broadcasts individually. However, public listening and distribution of the recordings are criminal offences. A listener in the South Korean Metropolitan area (Seoul, Incheon, and Gyeonggi Province) or near the DMZ who tunes across the MW band may hear strange signals on several MW frequencies, mixing with North Korean radio broadcasts. These include 657 kHz (PBS Pyongyang), 720 kHz (KCBS Wiwon), 819 kHz (KCBS Pyongyang), 882 kHz and 1080 kHz (KCBS Haeju).

The South Korean government broadcasts several bizarre-sounding jamming sounds (usually warbling or chugging) in an attempt to prevent their citizens from hearing radio broadcasts from the North. The medium-wave jamming by the South is sometimes too weak to completely block the North Korean broadcasts (the jamming transmission power seems to be between 20 and 50 kilowatts, while the targeted North Korean transmissions are of much higher transmission power -- typically over 500 kilowatts).

Radio jamming in North Korea

Since it is illegal for North Koreans to listen to anything other than state-run radio, all legal radio receivers are sold fixed so they can play only channels approved by the government. Because the receiver channels are fixed, North Korea does not need to jam any South Korean private television and radio broadcasts (such as MBC, SBS, etc). North Korea does jam some of South Korea's state-owned radio and television broadcasts. Before the (early 2007) closure of South Korean shortwave domestic radio broadcasts (which were often targeted at the North) 3930 kHz KBS Radio 1 and 6015 and 6135 kHz KBS Radio Korean Ethnicity (formerly KBS Radio Social Education) had been severely jammed by the North.

The type of the jamming on shortwave is 'Jet Plane Noise', which makes it very hard to hear the radio broadcasts. North Korea also jams South Korea's clandestine shortwave broadcast, Echo of Hope, and the South Korean international shortwave broadcasts of KBS World Radio on 5975 kHz (discontinued as of early 2007) and 7275 kHz. The South Korean national radio channel, KBS Radio 1 on 711 kHz medium-wave is also jammed by the North. Before the bilateral declaration in 2000, KBS Radio 1 used to deliver certain programmes (merged with then KBS Radio Social Education) which condemned the North Korean regime during at midnight. A visitor to coastal areas of the Yellow Sea (covering coastal parts of Gyeonggi Province, Incheon, Chungcheong, and sometimes Jeolla regions) who tunes into 711 kHz (KBS Radio 1 Seoul) may hear strange beeping sounds, which seem to be jamming signals from the North.

Strangely, the North does not usually jam the medium-wave transmissions of South Korea's broadcast towards-the-North, KBS Radio Korean Ethnicity (formerly KBS Radio Liberty Social Education) on 972 and 1134 kHz. It should be noted that KBS Radio Korean Ethnicity actually no longer targets North Koreans since the North-South Korea Joint Declaration on 15 June 2000. As of 15 August 2007, the radio channel has changed to a special radio broadcast for ethinic Koreans in Northeast China and Far Eastern Russia.

North Korean jamming of television broadcasting is relatively unusual, although the North Korean regime once severely jammed a South Korean state-owned television broadcast (KBS TV1 on VHF ch. 9 in Seoul) in the 1970s. Currently there seem to be some strange signals on VHF ch. 9 in Seoul which seem to be North Korean's jamming, especially in the evening. This jamming is not very effective.

Because of electricity shortages in North Korea these days, the radio jamming activities are not always consistent and are sometimes interrupted by power failures.

Protest to Libya after satellites jammed

• David Hencke and Owen Gibson
• The Guardian, Saturday 3 December 2005
• Article history

British and US diplomats have protested to the Libyan government after two international satellites were illegally jammed, knocking off air dozens of TV and radio stations serving Britain and Europe and disrupting American diplomatic, military and FBI communications.

Among stations hit were digital broadcasts by Five, BBC World, CNN International, US sports channels, cable TV networks and 23 radio stations. According to an email sent by one of the satellite owners, Loral Skynet, the US state department said it "would take it into their own hands" unless the interference stopped.

Last night the Foreign Office confirmed it had raised the issue in talks between the British embassy in Tripoli and the Libyan government.

Ofcom, the telecoms regulator, said it was considering taking a complaint to the International Telecoms Union.

The jamming started on September 19 after the launch in London of a small British and Arab-owned commercial radio station broadcasting on human rights and freedom of speech issues to Libya.

Ten minutes after the station - initially known as Sout Libya - went on air a transponder carrying the station was jammed for 50 minutes along with other stations. The jamming stopped when Sout Libya stopped broadcasting.

The station relaunched as Sowt Alamel, this time through a new satellite called Telstar 12. As a precaution, the broadcasts were sent to the US first, and then beamed up to Telstar, making it impossible for anybody to jam it, except from America.

Yet the moment it went on air, the jamming started again, knocking out the other stations without affecting Sowt Alamel.

An anonymous email sent to a company which helped the station said: "We can tell you we know the reason for these problems, it is the presence of the so called 'ALAMAL' radio Audio channel on your satellite. This channel broadcasts terrorist propaganda, intended to spread terrorist ideas amongst the listeners mindes [sic]."

The station has now voluntarily agreed to suspend its service. Its director, Jalal Elgiathi, said: "Our radio station had commercial advertising and altogether we have lost £250,000."

Last night 10 parliamentary questions were tabled by Andrew Mackinlay, Labour MP for Thurrock and a member of the Commons foreign affairs committee. "We need a full explanation of what has happened and whether Britain has insisted as part of its trade talks with the Libyans that it respected international law."

Industry sources confirmed that Five had lost its signal from the satellite, but said that the situation had been "quite quickly resolved". Other broadcasters were unaware their channels were affected. A BBC World spokeswoman said: "We're consulting with our cable and satellite partners in the region to clarify the situation."