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Jamming Cellphones in prison
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I think that they can and should do tests to see just what collateral damage is done to other wireless signals and services. What do you think about such things? |
Once again the age of our legislators is showing. Just about every 'technology' issue that comes before Congress is decided by technologically illiterate old white men. I'm sorry to say, but they're way behind the curve.
It sounds like a great idea, until you consider that "jamming" a signal, even in the military sense, is nearly impossible. From a general policy standpoint, I think preventing cell phone use by inmates is a good thing. But from a technological standpoint, I think that it is just not feasible. Perhaps that money should be spent on getting less crooked guards? The real WTF is "Prisons have used cellphone trackers and mobile phone sniffing dogs to try to find rogue mobile phones".. phone sniffing DOGS? What?! |
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WTF? We can jam Bunny the Fister's cell phone in the state pen, but the asshole that uses his in the theater goes unchecked?
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This is a thorny problem. It's a massive setting of precedent to allow any jamming of electronic signal in the US at all. How long until theaters and then private homes jam certain frequencies? On the other hand, prison's a pretty good place for a criminal boss to work from--three squares, you're relatively safe, you don't have to do anything to get along, and you can direct traffic outside via text messages. On the other other hand, I wish it was easier for most inmates to be in contact with their families. I want that guy texting his daughter every night to be able to do that. It'll be better for him, and it'll be WAY better for his daughter. I don't have a good answer for this. |
How much wireless technology, other than CB, which operates in a different frequency to cell phones, do prisons use? Do they all have wifi or something?
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I'm still skeptical. I wanted to see the dog respond on the protocol box, the handler open the box and reveal to the camera nothing but a phone. How do we know that there was a phone in the box and not a one-pound bag of weed? Because the guys running the deterrence program told us so.
A dog can be trained to detect just about anything...but cell phones? I cant imagine what unique odor they would give off. Plastics are common in prisons, as are electrical components (electronic key pads, computer systems, locks, CCTV). Maybe the lithium/nickel batteries...but most hacks carry Surefire flashlights (especially during a cell search) that use 123v lithium batteries. I'm more inclined to believe that the cell phones that are being found were hidden alongside the prisoners drug stash. The dog responds on the drugs and cell phone is discovered along with it. The dog handler tells the prisoner that the dog was actually detecting the cell phone. That misinformation is then spread throughout the inmate population, thus deterring the inmates from trying to get away with an illegal phone. |
If they can smell cancer, they can smell pretty much anything.
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All cell phone towers operate on three uni-directional sectors that that are roughly separated at 120*. These prisons could've just gone to the cell phone companies and ask them to swich off or reduce the footprint of the sectors of any site that points at the prison. It's not 100% effective, as a cell could possibly reach the remaining sectors pointing away from a prison (but have poor call quality), but it's much less disruptive than jamming.
Certain technologies, such as CDMA are also more resistant to jamming because they operate simultaneously on multiple frequences rather than just one frequency. The amount of power needed to jam a CDMA signal would be disruptive a more than just cell phones. |
Are you fucking kidding me?? Prisoners have cell phones? I say kill them all. Forget spending money on expensive technology to jam frequencies. Yeah, you know that guy who stole a shitload of money and we should sing "kumbaya" for him because he is "doing his time" ... kill him too.
What the fuck is wrong with the people against this? Staying in touch with their families? What?! Yeah, career criminals also enjoy long walks on the beach, candle light dinners and reading romantic novels. How is a prison safe if the inmate has a cell phone? |
Im with you Will. But from what I understand, cancer and the bodies reaction substantially alters ones chemical composition - thats what dogs hit on. Dogs aren't trained to detect marijuana and heroin per se, they are trained to detect the unique chemical compounds in THC and opiates.
Nerds unite and help me out. Does anyone know what would make a cell phone chemically unique in an environment full of plastics, hand held radios and electronics components? /sorry for the thread jack |
Yeah, dogs can categorize items by the combination of odors an item emits. Cell phones have a unique scent compared to televisions or radios. Each type of electronic requires a different combination of materials--at different proportions--for them to work. Dogs can be trained to sort that kind of thing out.
I think prisons should control the use of cell phones, as its a matter of public safety. |
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I know nothing of the technology required to jam a cell signal but I can't imagine that the cost of implementation and maintenance would be cheaper than stepping up security to crack down on smuggled phones and expanding the preexisting means of communication.
I also don't think it reasonable to expect inmates not to have any contact with the outside world beyond the allowed means of communication - where there's a will there's a way. And also, am I the only one who sees this becoming a Movie of The Week involving a prison riot, trapped guards and blocked cell signals? Quote:
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^^ No not really.
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This really comes down to cost. The costs involved in policing the situation (i.e. making sure that prisoners don't have mobile phones) versus simply making the mobile phones inoperable are incomparable. It's much cheaper to just switch off the signal.
You aren't going to get the funding for the former. They need to develop a system where they can effectively turn off the coverage for a prison. It will have to do with the placement of cellular towers rather than jamming. |
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The problem is that cell phone technologies don't rely on a single transmit and recieve frequency. You'd have to either buy multiple jammers for each frequency or one jammer powerful enough to block out a block of frequencies. The problem with the former is the unintended harmonics that are generated will cause inteference. The latter will knock damn near everything off the air. And something that powerful you don't want to be in the vicinity of. |
I don't understand the arguments. The whole "it's hard to jam" does not stand up. It's hard to go through every letter every time too make sure nothing gets through, but it still does and always will. It does, however, make it more difficult and will stop the majority of communication.
Jam the hell out of cell phones as it combats the communication of gang leaders who still control operations on the streets. |
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Portable cell phone jammer cellular phones jamming for blocking mobile phones I'm all for them at SuperMax prisons. But I think that phone calls and real world information/news should be used as a reward for good behavior in a typical prison with non-violent criminals. |
AFAIK cell phones operate on about 3 defined freq. bands.
Why can't the prison monitor for local activity on those bands? On a cell block basis. Equipment informs staff and blocks that freq. band with a low power signal that is wideband or sweeps the band confusing the trunking. Just a thought. |
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^^ Sure, let's throw our hands up and not do anything then. I mean, they'll send messages out anyway, lets not even bother imprisoning them.
I still have no idea why there are folk against jamming the signal. CDMA does work on multiple frequencies but it also has to be a designated frequency. Let the inmates go back to codewords and notes. Besides the digital nature of these frequency transmissions will ensure all non-FM/HFM frequencies don't get through. EDIT: I meant to say CDMA works on multiple channels of the same frequency. |
Two words: collateral damage.
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CDMA is a different animal. It's developmed from frequency hopping technology pioneered in WW2 that was designed to circumvent enemy jamming techniques. CDMA is difficult to jam because those six CDMA bands that the FCC licenses out is between 25 and 60 MHz wide and that signal uses all of that single band to transmit. To jam a CDMA signal, you'd have to jam the entire band that it operates on. With that said, I have to question the effectiveness of any broadband jammer (especially the portable unit ASU2003 showed me) to effectively interfere with a CDMA signal (such effectiveness at preventing an IED from being triggered has already been called into question by some in the defense field). As a jammer's bandwidth increases, it's effective power decreases without significant amplification. If a signal is too powerful, rest assured it's mucking up other forms of wireless communication through the introduction of excessive noise. I'lll give a better explaination tomorrow, because I'm dead tired. |
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Such civility. I have to admit that the first thought that popped in my head was pretty much the same as Xerxys'. However, I do have a filter in my head :) |
says a whole lot about prison security when a death row inmate can get hold of a cell phone. i feel safer already.
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Well, when you have a system that incarcerates 1 out of every 100 citizens, it does get a bit challenging to manage down to the last detail, doesn't it?
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How much would it cost to make the whole damn building a giant Faraday cage? I don't know, and it's probably too expensive, but I don't think jammers would do the job well.
I think the problem is the same one that's existed for years: inmates can still have contraband in their cells, and are quite creative with the way the smuggle/hide it. The corrupt COs don't help either, since they're the reason people can get stuff in and out of the system. |
eh.. put me in the camp that thinks we should focus on real rehabilitation rather than "break them down as much as possible". Sure, it's a prison. There are bad people there. I get it.. but really.. how does a bad person full of evil thoughts and hate turn those thoughts around? By being hated on and screwed for however long they are in there? Doesn't make sense to me.
Xerxys. Kill them all? really?? Please.. PLEASE call me first if you ever get arrested and put in jail. |
^^ Dude you don't understand, it's not the inmates that "keep in touch with their families" that have cell phones. Think about the value of a cell phone and tell me if it's going to be used to keep in touch with their families. A cell phone has to be up there with money and availability of procuring goods in time for demands.
An inmate with a cell phone has to be just as dangerous as one on the loose. |
right..but if we focused on actually rehabilitating people instead of treating them worse than dogs, we wouldn't have issues such as these now would we?
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Problem 1: CDMA is too resistant to jamming. I can't explain this enough. CDMA broadcasts on such a wide band that any rf detector trying to pick up a CDMA signal will not distinguish it from background noise. It would look like an elevated noise floor. Since a broadband jammer puts out white noise, a CDMA phone and tower would have no problem filtering through it. Btw, good luck trying to power a 1.9 - 2.1 ghz jammer with a 4.5v power source. Problem 2: while there are 3 gsm bands licensed by the FCC, each band holds approx 250 channels. Provided you do find what frequency the paging channel is operating on, once the carrier discovers that it's being actively jammed, they'll change the frequency of that paging channel. It'll be an endless cat and mouse game until you're slapped with an injunction to stop intefering with their operations. And good luck trying to power an 850 or 1900 MHz signal with only 4.5 volts of power. |
Oddly enough in my office right now I get no cell signal because I'm in a cast iron building in the dead center. sucks up my battery like you wouldn't believe!
Agreed, you'll need some hefty wattage to stamp out the other signals. |
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you don't. they are not interested in rehabilitation. |
TBH, the military possess electronic warfare technology that can inhibit mobile phone signals (i.e. to stop bomb detonation), it's not going to be hard to get something along the same lines for prisons. I have no doubt that a government department will have plenty of co-operation from phone companies in how to block their signals.
Failing that, you can brute force deny the operation with transmitters. If your only trying to deny access to a small area, it's not overly hard. To everyone saying they should beef up security, don't you think they've already tried that? I can understand the toleration of illicit phones to non-dangerous or rehabilitating prisoners, but the kind of people that this article is aimed about are end of the line convicts. An answer for non-risk prisoners might be to supply mobile phones with a pre-programmed set of numbers that they receive for good behaviour, which can be externally monitored. I also suspect that new high tech prisons will employ some sort of faraday cage design to prevent this in the future. |
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