July 10, 2003
Who's Jamming, And Whence?

Both VodkaPundit and (with more detail) Electric Venom report that Iranian-language broadcasts from the U.S. are being jammed (which did not surprise me) from somewhere in the Americas (which did). I'm wondering who is operating the jamming equipment, where they are located, and what (if anything) can be done about them. I don't understand the physics, but I'm guessing that it takes fairly expensive equipment and quite a lot of power to jam a satellite from the ground. Venomous Kate reports that the jamming is not coming from near the source of the broadcasts in Southern California, but from somewhere further east, aimed at a linking satellite over the Atlantic.

The Who and Where questions go together. I see three possibilities. In no particular order:

  1. Iranian agents on a ship (not necessarily Iranian-flagged) in international waters. Would an unobtrusive cargo ship have the power to do this? Would it have the stability? (I wouldn't know, but I wonder if a ship at sea would slosh around too much in the swell to keep a steady jamming beam aimed at a satellite, at least without some very sophisticated aim-correcting equipment.)
  2. Iranian agents on the ground in some country that doesn't know they're there. In that case, countries with huge expanses of jungle and poorly-guarded borders are most likely, but there are at least half a dozen countries in the area that fit the bill, for instance Brazil, Colombia, Venezuela, Guyana, and Surinam.
  3. A government in the area that shares Iran's hostility to the U.S., most likely Cuba or Venezuela. (I hope the French aren't perfidious enough to let them use French Guiana.) In that case it hardly matters whether the jamming is being done by the government or by Iranians they have allowed into their country.

What can be done? Again, I know far too little about the science and the law to answer my own questions. Here are three more, one for the engineers, two for the lawyers:

  1. Can a jamming beam be easily tracked and located? I'm guessing not: if a radio station directed a focused signal straight at the satellite instead of broadcasting it in all directions, wouldn't it be impossible to detect without actually flying a plane in between? Even if the beam tended to spread, a station in a deep valley surrounded by mountains would surely be undetectable even in the next valley. (I hope the signal's not coming from a holler in West Virginia: that would be embarrassing.)
  2. Isn't this jamming a gross violation of international law? It seems to my legally-ignorant eye to be equivalent to piracy. The fact that property is passing through international waters (or space) and is (in this case) intangible doesn't mean than anyone is allowed to hijack or destroy it, does it?
  3. If jamming is equivalent to piracy, can the jamming transmitters be destroyed by the countries whose signals they are jamming? I believe the Navy is allowed to destroy pirate ships, at least if they are intercepted while committing piratical acts. I believe this is true even if the pirate ships are not in international waters, but in the waters of a country that is either unwilling or unable to stop their pirating. I assume jammers would have to be given a chance to stop jamming before launching cruise missiles at them. If they are located on land, the countries harboring them (knowingly or unknowingly) would also, I assume, have to be given a chance to shut them down themselves. But if they refused to do so, would we be free to fire off a cruise missile or two?

Can anyone help me out on these questions? Steven Den Beste? Steevil? (That's my brother the electrical engineer.) Anyone else? Maybe I should ask my father, who I believe helped jam radio stations in the Dominican Republic during the U.S. intervention in 1965. Then again, his knowledge of jamming, though practical as well as theoretical, may not be quite up to date.

Posted by Dr. Weevil at July 10, 2003 08:05 PM

The LORAL URL for Telstar-12 is

They summarize the visibility (hence area in jammers could be located--

"Coverage: North America as far west as Cleveland and Atlanta, and the majority of South America; Europe as far east as the Ural Mountains and south into North Africa; the United Arab Emirates and South Africa."

The links are Ku band, so in the 13-14 GHz range. A fairly small (I consider 20 ft diameter small) antenna can put a tight beam on the satellite at this band.

No antenna radiates perfectly in its main beam. It alway leaks power into sidelobes. I would hope that the USAF is looking for (from orbit) unauthorized radiators.

Posted by: steevil (Dr Weevil's bro Steve) on July 10, 2003 11:53 PM

Hmmmm, the question is then can HARM home-on-jam mode use that band ... I hope so.

Posted by: Robin Roberts on July 11, 2003 01:22 AM

I saw a relevant article yesterday (but I didn't keep the link). It said that first attempts to triangulate suggested a jamming source in the border area of Argentina and Paraguay. This is a well-known trouble spot: one time Nazi refuge and current hangout of Hizbollah operatives suspected in Buenos Aires bombing of Jewish center.

BTW, glad you're back after hiatus.

Posted by: Alan Sullivan on July 11, 2003 02:43 PM

As your brother says, side-lobe detection would be the way to go, once the approximate area had been located. Detection from space would be problematical as side lobes are highly attenuated relative to the main beam and also are likely to be off-azimuth to a great degree. As for the legal status of an attack on the jammer - that would be extremely problematical. Although the jamming could perhaps be considered an act of war, any retaliation against it would perforce be such an act. However, if the jamming is coming from an area that is only nominally under governmental control (the wilds of the Paraguayan border fit the bill) then I would not put it past the powers-that-be to arrange - probably with tacit approval from the local government - a covert operation into that area to destroy the jammer (and with luck kill the agents involved). Launching an anti-radiation missile would not be very covert. Deploying an ELINT aircraft over the region (call it a 'training exercise') and then sending the boys in the Nomex jump suits in is the way to go. If the jamming goes off-air and a bunch of Iranians turn up with bullet holes in them, the mullahs can hardly protest.

Posted by: David Gillies on July 11, 2003 03:58 PM

I won't dive into the technical aspects of the issue - they are actually relatively simple, yet with a needle in a haystack flair.

As for interdicting/stopping the intrusion/jamming, unfortunately, most of the sat jamming appears to be directed at the non-governmental stations originating from LA. Interference, jamming and other forms of disruption of this sort have been stock and trade of regimes since before WWII - and although odious, they aren't considered sufficiently heinous acts to provoke the kinds of response that you're discussing. Such uses of force, outside of wartime, would be deemed an excessive over-reaction. On the flip side of the argument of 'hey its not fair to mess with our signal' is the counter of 'hey, you are violating our soveriegn territory with 'hostile' emissions', both of which are actually valid gripes.

If the source of the jamming/intrusion signal is from a sovereign, third party state, pressure could be applied to have them track down and apprehend the source of the jamming - but, that would take time. If it is in the US, it would actually be more difficult to actually do, because of the restrictions the Government has placed upon itself about what resources it can use inside, as opposed to outside the country. And in either case, the complaint would have to come from the broadcasters, and a sufficient level of concern/interest/priority placed on the affair to have action taken. Probably not likely.

Unfortunately, this is a stunt that the mullahs have very little concern about repercussions over, with good reason.

Posted by: Wind Rider on July 12, 2003 12:10 AM

A little birdy told me it's Cuba. And far as I know, jamming is legal. Folks did it all the time during the Cold War.

BTW, if you need any content for the Snopes/Political FAQ, lemme know.

Posted by: Anticipatory Retaliation on July 16, 2003 02:32 PM

But why not put jamming beams all over Iran? That way, the mullahs would have the power to jam whatever they wanted. I understand this is how the Soviets did it. All major Western shortwave broadcasters (the Voice of America, the BBC, Deutsche Welle, Radio Liberty) had transmitters close to Soviet borders (in Central Europe and Turkey), so the only efficient way to suppress them was to install a jamming network in European Russia. It didn't cover 100% of the area, but it worked well in the big cities. They also changed jamming intensity depending on the subject.

Since I grew up there and then, I still have vivid memories of listening to jammed broadcasts. However, non-Russian-language stuff was freely available, and since the Soviets more or less encouraged foreign language instruction, some of the smarter folks could use that leeway.

Posted by: Alex(ei) on July 24, 2003 03:16 AM