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Jamming devices?

17 Jul 2009 18:3929 Comments
Parazit-Borje Milad-3

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Parazit-Borje Milad-2

Parazit-Borje Milad-1

From an Iranian source in the Middle East [unconfirmed] | "Satellite jamming devices (manufactured locally by Saberin Co., an IRGC company) installed on Milad Tower. "Now we know why Milad tower was constructed. The current jammers have capability of jamming satellites serving the Middle East, Turkey and Europe as we have seen during past few weeks." Can anyone help confirm or disprove this?

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I think it is a rumor, i used to be an electrical engineering student, these have fans, so definitely something is overheating in them

but i do not understand why they look like speakers. They have some cables, like computer wiring. I do not know, it could be true, is there any report of successful parasiting? another thing, the way they are intalled they cover portion of Tehran not all of it. I would think you would go for maximum coverage with these things.

former ee guy / July 17, 2009 2:56 PM

Someone is going to have to convince me those are sat jammers before i forward that to anyone!

alex / July 17, 2009 2:59 PM

These look like standard cell phone signal-emitting devices, like we have all over in Brooklyn, NY, USA. But I'm not sure.

Todd / July 17, 2009 3:04 PM

I believe you are correct in that they are jamming devices, however I think you're way off on their capabilities. There are reports that even on the outskirts of Tehran, where there is the worst jamming, you can still get BBCPersian. To say that this tower have the "capability of jamming satellites serving the Middle East, Turkey and Europe" is an overstatement.

That said, there may be other locations with this sort of capability. Isn't BBCPersian still static for most of urban Iran?

emsenn / July 17, 2009 3:05 PM

Someone place a bomb at the bottom of the tower and explode the whole thing.

Freedom / July 17, 2009 3:30 PM

I dont know if these are jammers, but there are jammers somewhere, specially after every major protest, the get no signal. All my family memebers call me for because they lose signal and have no trusted source of info.

I don't see the point of jammers not having fans. Most electronic devices have fans depends on how they designed..

Nikki / July 17, 2009 3:34 PM

Spent awhile looking for these elsewhere on the net. Couldn't find a reference to the part numbers, but studying the number sa 87 jrs 40 00 s indicates they may be related to satellites. Just some guesswork here which will certainly be flamed, but "sa" may refer to "satellite" - "jrs" could be "jamming/repeating station" or something similar.

I doubt that the part number would refer to the unit as a "jammer", though. To jam a signal all you need to do is broadcast a stronger signal on the same frequency. Most likely these are repeater modules for a valid signal, which may or may not have been used to jam other signals.

Jon / July 17, 2009 3:52 PM

i showed those pictures to an engineer who says it must be broadcasting devices of some kind.

according to the allignment of the devices he says that they are unlikely (but not impossible) to be satelite jamming devices.

he agrees on the fans (as the guy below mentioned) so there must be a lot of heat being generated inside those things which leads to the conclusion that they could be transmitters (transmitters generate energy which often results in heat)

his general assumption is that those things could be devices to jam the mobile phone network. according to the way those devices are trained downwards to cover the space below the tower they could generate a dampening field over the existing network.

after showing those pictures i did some research and found out that satelite-receiption can be jammed by emitting radio waves in the frequence of a DECT cordless phone. gsm signals can also interfere with satelite receiption when they are strong enoug.

it would be interesting to see what parts are put inside those protective boxes for a detailed result.

no more confirmed data for the time being

radio-dude / July 17, 2009 3:59 PM

I don't believe they're satellite jamming equipment. They're pointed down toward the city. The size would indicate that they're probably designed to capture microwave transmissions. Meaning cell phones.

Bob D / July 17, 2009 4:06 PM

If, as some evidence suggests, they are going for a N Korean model of complete media control, which seems to be possible given the level of fanaticism shown towards dissenters, then they would have to be able to block all other channels and completely suppress any other form of content distribution except that sanctioned by the state.

It is consistent with the installation of a cult of "the Supreme Leader" which requires a uniform level of mind control with no external disruptions; brainwashing, in other words- of which there are many signs in the Basij. The question the dictator would have asked himself probably went like this: If I can create a group of 1,000,000 unquestioning followers in an indoctrinated militia, what could I achieve if I indoctrinated all 70 million Iranians with a total media environment saturated with only my own image and my own words.

Basij training manuals equate Ahmedinejab with the 4th Imam, obviously deserving of unwavering loyalty and unquestioning obedience.

You can work out the social pathology of this regime from there by observing their frantic and increasingly futile efforts to control what is self evidently a media/political/social revolution with its own ideas- We are the media. The next revolution is already being fought In Iran. The Iranian people are the front line.

Go for it Iran. Freedom is worth the price. I hope you do not have to pay much more than you have already laid down. You are an exemplary people in the tenacity of your courage and the audacity of your faith in the truth, in and of itself, as worth standing up for.

Mike Ricks / July 17, 2009 4:15 PM

the best part is they spelled model wrong...

stupid idiots.

just goes to show the best and brightest dont work for the IR Iran government

samadagha / July 17, 2009 4:20 PM

I haven't worked with that type of equipment before, but my specialty is EM, so I'm going to make a shot in the dark. If they were pointed upward, the only thing they'd be jamming is the uplink to the satellite. If they wanted to jam reception devices on the ground, they'd be pointing the way they are now: where the signal they transmit can be received by ground devices. That said, I'm not sure why they'd be running around taking people's satellite dishes if they have the capable to jam them. On the other hand, maybe these are design to jam ground reception at certain frequencies. Since the BBC is trying to change satellites and thus potentially the frequencies, it might make these particular devices useless as they've found a work-around...so they started taking the dishes.

The front look like speakers for two reasons. One is that they're probably trying to minimize the amount of dust, so they have a screen over them. However, the cases look like metal, so if they are transmitting a signal, they need to have an opening in the front that is a certain fraction of the signal wavelength. Satellite broadcast frequencies are in the 10 GHz and up range, so ideally you'd want an opening about 15 cm (across). With cell phones, I can't tell based on the size. It might very well be large enough to broadcast at those frequencies as well. (Lower frequency -> larger opening because of the longer wavelength.)

So if someone was brave enough, they could slap some aluminum foil over the front of these and see what happens. Doing that would probably cause them to overheat if they really are transmitting enough power to jam a signal.

And that is my 2 cents. :-)

Cherish / July 17, 2009 4:31 PM

I guess I forgot to state this explicitly: a signal can't escape from a metal box, so putting aluminum foil over the front would block any electromagnetic signals as well as wreck the fans' ability to cool the system.

Cherish / July 17, 2009 4:34 PM

Very subtle hint:

Nice. .300 Win Mag with a decent 26" barrel capable of 1/4 MOA accuracy benched from 1500 yards should do a nice job.

John Morrison / July 17, 2009 4:39 PM

those are cell phone antenna mounts meant to aim at a certain level obviously, going in the back looks to be 1 electrical water tight connection and one coax connection,not your normal household coax but more the kind used on tower or rooftop cellular sites..

as far as what they are? they could be jamming systems or rf tracking systems or even systems to disable remote devices like key fobs or garage door or IED remote detonated devices..maybe even camera systems, it looks to be a quick a shoddy installation so i would bet it has something to do with the protests..

really though it is kind of like cracker jacks in that anyone can buy a hoffman type box of any size and install fans so whatever is in it is a mystery more less.. but it is placed and aimed on cellular antenna brackets and has power and coax to connected..

I used to install communication towers and it is like no antenna i have seen.. i will email it around and see if i can find out..

one more thing there are many types of cellular jam systems right down to Walkman size to suitcase size and on to bigger rack system type jammers.. these will all either have antennas sticking out of the device (smaller devices) or have wires going up a tower or building etc to antennas..

here are examples





richard cranium / July 17, 2009 5:27 PM

Did a little googling, found a similar looking Cell phone network jamming devices here:

http://cjam.com/?page_id=51 --> This is the website for "Cellular Jam" a division of the company listed in this article: http://www.engadget.com/bloggers/barb-dybwad/page/15/

I wouldn't say it is the same thing necessarily, but it looks similar. They say their system has a range of about 100 ft. I would guess different mfr's have different ranges and they might have an advantage being at the height they are and with a couple dozen together

Davey Crocker / July 17, 2009 5:43 PM

If all these jamming signals come from one single tower, then it might be possible to reduce the jamming by putting some metal shielding next to your satellite dish, so the tower is not 'visible' from the dish. A metal mesh should do the trick. The holes in the mesh should be clearly smaller than the wavelenght of the signal.

If shielding turns out to work, and if the best place for the shielding is always towards this tower, for people in different locations, then that would stronly suggest that the tower is the source of the jamming signal.

By the way: it would probably not affect your dish if you hide it inside a non-conducting box, so basiji will not know to come and get it. Might be a problem during rain.. so you'll need to experiment a bit. You could attach the shielding to this box.

Nichol Brummer / July 17, 2009 6:35 PM

Just more blind speculation but:

This tower seems to be on the North side of town.

Wouldn't most satellite dishes be pointed toward the south?

Doesn't matter much if the signal is strong enough - or if there were multiple locations (as would seem likely).

Shouldn't be hard to get a fix if someone on the ground swings around their dish a bit.

z616 / July 17, 2009 7:36 PM

Looking at these boxes, I'd say theres a far bigger chance of them being something comercial rather than produced for government. The small sticker on the upper left of the second picture, looks like a standard "Warranty void if seal broken" sticker that you tend not to see on government equipment.

Jamming equipment for cellphones is a complete waste of money. to stop cellphones working in an area, all that has to be done is turn the individual tower off, or stop all signals from that cell routing at the central control. (cell systems can have an emergency services override, that shuts non-registered phones out of the system too)

ceebs / July 17, 2009 7:59 PM

It appears this story originated on the following July 3 blog post (in Farsi).


That page appears to have much more information, but the Google Translate is unclear. Maybe someone could summarize it?

z616 / July 17, 2009 9:23 PM

I get BBCPersian near the mosallah in tehran

Ali / July 18, 2009 2:49 AM

I had a friend of mine, who is a professional broadcast engineer, have a look at these. He reckons they could easily be Satellite reception jammers, *IF* the comment from emsenn(/ProtesterHelp?) above "There are reports that even on the outskirts of Tehran, where there is the worst jamming, you can still get BBCPersian." is correct.

He says that the jamming signal would not have to be very strong to overwhelm the satellite transmission regardless of direction, but that obviously - the further out you more, the weaker the jamming signal will be.

In which case, it may indeed be quite simple to block the jamming signal with an earthed metal shield between a dish and the tower (we didn't talk about this, but if it's confirmed that the jamming signal is less effective the further away you get from the tower, then we can easily get expert tips on how to block it.

Jaymax / July 18, 2009 3:52 AM

I liked the idea of the winchester magnum, but of course

no one in iran has guns save the regime and its accolytes.

However, let's combine the idea of the tin foil and jammer

and fight waves with waves of a very different sort.

If anyone has access to nearby rooftops and to good mirrors,

otherwise grab those broken satelite dishes wrapped in foil

and point them straight at the boxes.

let's fry the units from a safe distance.

iran_revolt / July 18, 2009 4:16 AM

btw. milad tower is a computer/telecomm center, read a sigint center.


iran_revolt / July 18, 2009 4:28 AM

To the too many people wildly speculating about cellular jamming devices. Please understand that the Iranian gov controls the mobile communications network and all other communications infrastructures, and could (and does) selectively or completely shut down these networks.

I also suggest to those kind enough to offer home made solutions, to experiment first and after getting solid results, publish their recommendations. When an LNB is bombarded with ~50watts of noise, the sub-milliwatt DVB signal from the satellite transponder reaching the LNB has no chance to compete.

We should focus on long lasting and logical solutions: participating in positive action to eliminate the source of the problem, and regaining our freedom.

ferdosi / July 18, 2009 6:09 AM

They might be jamming devices, but NOT satellite ones. If you look at the pictures they are all aimed downwards. Satellites, whether geostationary, or low orbiting are all above the horizon. Further more to over power the existing uplink signals will require a very much larger dish than any normal domestic device, let alone the small antennas shown above.

microdave / July 22, 2009 6:10 PM

Microdave: The power from satellite downlinks is of a small magnitude; do you not think it is easier to literally swamp the satphone with suitably modulated RF of a much higher magnitude to deny the user service?

Sal ibn Hari / July 23, 2009 3:12 AM

Sal ibn Hari - Yes It would be quite easy to "swamp" satphones over a limited area, but the article above says "The current jammers have capability of jamming satellites serving the Middle East, Turkey and Europe as we have seen during past few weeks."

I found this post from a link on another site, so I'm not sure exactly which satellites are being referred to, but I assumed they are direct broadcast ones, which rely on highly directional dish antennas, both on the satellite, and on uplink and reception sites.

Microdave / July 23, 2009 3:31 PM

The second photograph is the series is not of the equipment shown in the other photographs. Notice that the mounting plate at the base is different, and in the second picture we can see the top of the enclosure (which is small), and yet in all the other picture the enclosures are quite large.

The connector on the second photograph is a typical military connector, but non of the other photographs show a connector of this type.

The second picture is also of a notably different size, appears to have been taken with a different camera and lenses, and even looks like it was taken with flash whereas the other pictures were taken with ambient light, obviously outdoors.

Also there are no close up photographs of the taller enclosures, only of the small enclosure, and no photographs of the markings or labels on the taller enclosures, just of the small one. In fact the small enclosure is not even present in any of the photographs of the taller enclosures.

The taller enclosures have cable that is appropriate for a listening devices, not a jamming device. There is also a window that can be observed on these taller enclosures, but the photographer did a poor job of taking the pictures so that you can not resolve either the size of the window, or what is behind it.

Due to the poor quality photographs it is as likely that these boxes are part of a weather station as as much as they could be part of an eavesdropping system, or a jamming system.

The masts on which these enclosures are mounted seem to be sturdy and permanent in nature, but the enclosures and brackets for the enclosures appear to be poor quality and mounted in a haphazard manner.

Between all of the photographs there also appears to only be a total of three of the tall enclosures, and not all of the masts are occupied, does does there appear to be any other evidence of other similar devices on other masts or mounts nearby, nor of shadows of such devices.

If this a jamming system the area which it would be jamming would be quiet small, and given the lack of cooling facilities of these devices they would not be using of displacing much heat, and hence would be extremely low power, and of little value.

Some much better pictures are needed.

Do not jump to the conclusion (or propaganda) that these are either jammers, nor eavesdropping systems until some better pictures turn up.

Where are the other pictures, and why does the second image look like somebody worked it over with Photoshop?

Also, why would a system made in Iran for use by their internal counter-intelligence forces have markings in ENGLISH?

More pictures are needed

James M. Atkinson / July 26, 2009 8:39 PM