Cellphone Jamming

Discussion in 'Off-Topic' started by Papabravo, Nov 26, 2008.

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  1. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    A recent rquest for a circuit on this subject triggered a recollection that somebody was seriously interested in this. Turns out it was prisons. What they want to do is set aside federal law on interference so they can prevent inmates from using cellphones. Seems to me that like BPL this is a really bad idea.

    http://www.statesman.com/news/content/news/stories/local/11/26/1126cellphones.html
    http://www.time.com/time/nation/article/0,8599,1861553,00.html
    http://www.greenvilleonline.com/article/20081126/OPINION/811260374/1004/NEWS01

    These were the top Google hits. If you think trashing wide swaths of the RF spectrum in an unfettered fashion is a good idea then these folks will love you.
     
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    I remember someone once describing BPL as like "Transporting natural gas in an open trench". Couldn't have said it better myself!

    eric
     
  3. markm

    Member

    Nov 11, 2008
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    How easy is it to locate a cell phone in use by radio direction finding? If they have the means of tracking down contraband cell phones and still can't eliminate them from the prison, then you've got to start wondering who is really in charge of the prison...

    Also, I have some suspicions about the real goal of suppressing cell phones in prisons. Most jails and prisons have a deal going where a subcontractor puts in phones for the prisoners and charges an appallingly high monopoly rate for them, mainly on collect calls. Prisoners are thus even more isolated from their families, their families suffer more, etc. - but the folks with contacts at the bureau of prisons are making a great profit, and you can't let cheap cell-phones interfere with that!

    OTOH, there are many genuine problems with allowing unmonitored conversations between prisoners and the outside - many prisoners will try to use such contacts to arrange for drugs to be smuggled in, con artists might try to reel in more suckers over the phone, imprisoned kingpins try to continue running their gangs remotely, and sometimes there's an escape plot. What makes me dubious about whether this is the real reason, is that many prisons monitor mail, internet, and land-line phones so poorly that all that is going on anyhow.
     
  4. HarveyH42

    Active Member

    Jul 22, 2007
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    The prison system seems to be a joke. It should be tough and unpleasant, not just an inconvenience. Those locked up should be held as an example of why laws should be obeyed. Family and friends of inmates should have done more to prevent the crimes in the first place. It's their choice as to how much cost and suffering they wish to endure. They don't have to accept collect calls, don't have to send money, visit, or smuggle contraband.

    Prison contraband should be a felony, and should add years, even if its only a cigarette or stick of gum. Aren't they locked up to learn to follow the rules? Considering price of a cell phone, doubt the savings is huge. If the phone is in the inmate's name, think he will actually be paying the bill?

    I don't believe a contraband cellphone would be intended only to reduce phone bills, it's for criminal intent, and should be dealt with accordingly for both the inmate and supplier.
     
  5. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    I take issue with the proposition that the incompetent managers in the bureau of prisons at the state level are going to be responsible for an unrestricted RF generator with no accountability. At least under current law they would be committing a federal offense and might end up in a facility similar to the one they are running without a federal legislative flim-flam like retroactive telecom immunity.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    While there might be a legitimate interest in jamming prisoners' cell phones, that is a small application and the local cell carrier can probably do the deed. Or even let the warden/police/FBI listen in.

    The potential for selfish misuse is there, and so AAC will not carry information on jammers of any kind.
     
  7. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    How exactly does the cellphone company get around the Federal Regulations. If I am trying for a DX contact on one of the amateur bands and the folks at the prison onveload my receiver front end, I will have a legitimate complaint and might be successful in shutting them down. That is why the people who want to do this NEED federal legislation to set aside Title 47 CFR Part 97.

    BTW DX in the microwave region may be only a few miles, on a really good dry day.

    If it is not OK for individuals to create "harmful interference" why then is it OK for the power company (BPL) or the bureau of prisons to do it? Where does it stop, where do you draw the line? Inquiring minds want to know.
     
  8. Dave

    Retired Moderator

    Nov 17, 2003
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    It is common for countries to have exceptions, not that I am saying that is right; for example phone jamming in prisons is legal in New Zealand, Mexico, France, and Turkey (although not strictly specified, the Police have exemptions which can extend to the penal system). Germany and Italy are proposing introducing jammers to the prisons. There are other exceptions in other countries; for example the government can use jammers in India, Banks in Pakistan, and Churches and Hospitals in Mexico.

    I guess the idea is to hyper-regulate the usage of such devices (rightly or wrongly).

    Dave
     
  9. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    In those places where it is allowed what is the collateral damage to other users of the RF spectrum? Can the interference really be limited to cellphones? I don't think it can, but I'm no expert on this.
     
  10. HarveyH42

    Active Member

    Jul 22, 2007
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    Maybe the jamming isn't just drowning out the cell frequencies with random noise, perhaps only requires sending out a simple code or signal...

    That one article, with the death row inmate hiding his phone in his rectum was kind of funny.

    Oh, if the jamming signal is low power, and kept inside the buildings, wouldn't think it would have much effect on anything outside the prison grounds. Really don't know much about RF...
     
  11. beenthere

    Retired Moderator

    Apr 20, 2004
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    Don't forget the Dept. of Homeland Security. Any motivated application of the rules (or simple disinterest in being bound by them) can be more than enough justification to snoop communications of any sort.

    Cell phone packets have headers, and a process of elimination should let equipment at the tower zero in on calls from behind the walls. It might be more interesting to listen in than to jam the calls. Or just to route selected calls to the bit bucket.

    Several years ago, our service was very iffy. The older analog phones were still being supported, and those signals stepped all over the digital phones. It certainly wouldn't take much RF at the right frequencies to jam things.
     
  12. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    I think the point about digital cellphones being different than analog ones is well taken. I also agree that there is no expectation of privacy and that listening in might be a very productive activity. So productive that they should probably give them free cellphones in the hope that they will be stupid enough to reveal valuable information. -- ROFL
     
  13. thingmaker3

    Retired Moderator

    May 16, 2005
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    I've only been in one jail. (I helped build it.) There was so much re-bar in the walls that cell phones would only work in the staff & visitors' cafeteria. Repeaters had to be installed for the guards' radios to work.

    Are there any FCC regulations against building a Faraday cage the outer walls of a prison? (I realize cost may be prohibitive.)
     
  14. HarveyH42

    Active Member

    Jul 22, 2007
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    I don't think listening to thousands of conversations would be all that productive, least not worth the cost. Not to mention the inmates would be harassing everyone they have a phone number for, just because they are bored/lonely/or nothing better to do. They should stick to land lines, and limit cell phones and radio transmissions to corrections personnel. Inmates really have too many rights and perks. It should be hard work, much more so than on the outside. Most of us work 8-10 hours a day, and we would hope these 'reformed' souls will as well, when they are released. Their food should be nutritious, and basic and bland (choke it down. if you want to live). They'll appreciate their freedom more.
     
  15. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    Even if all of what you say is true. Who will be accountable when problems arise if the provisions of Part 97 and other rules on "harmful interference" are set aside. That is the question I have asked repeatedly, while everyone seems to want to dodge answering it directly. Those who will exchange liberty for security deserve neither.
     
  16. Wendy

    Moderator

    Mar 24, 2008
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    When you start talking about prisons civil liberties are already restricted. Having said that, my personal opinion is any interferance with the RF spectrum with the sole purpose to disrupt it is bad.
     
  17. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    I was never talking about the civil liberties of prisoners. As a licensed radio amateur I have a legal right to my portion of the RF spectrum. I have a legal right to be free from "harmful interference" no matter where it comes from. If the bureau of prisons is allowed to be exempted from the provisions of Part 97 for its narrow parochial purposes; I want to know who I complain to when I am unable to use my radios becuase their RF footprint for jamming cellphones interferes with my ability to use my portion of the spectrum.

    Under current law, if I complain to the FCC, the prisons are obligated by federal law to take responsibility for their actions and mitigate my complaint. What is being proposed is that I should loose the ability to complain about their equipment when and if it generates "harmful interference". This is the same exemption sought by the electric utilities to prevent radio amateurs and others from complaining about the manifest interference potential of BPL. Fortuneatly the economics of BPL consigned it to an early, but perhaps not permanent, demise.

    This forum has already taken a position on helping people design build and test cellphone jamming equipment. There are still segments of government and industry that believe they have a right to engage in this activity. In fact it is against the law. That being the case they are seeking to amend the law without regard to the unintended consequences. Bad things happen when good people remain silent.
     
  18. HarveyH42

    Active Member

    Jul 22, 2007
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    I don't get it. If the jamming signal is low power, and confined to the cellphone bands, how does it disrupt communications off the prison grounds. I was under the impression that they were interested in jamming cell phones indoors. I haven't learn much about radio, but there seems to be limitations on distance. Devices of different frequencies, don't seem to interfere much with other devices on different frequencies. Although as a child, I remember my father cursing the man down the street with all the antennas on his roof for messing up the TV reception during football season...
     
  19. Papabravo

    Thread Starter Expert

    Feb 24, 2006
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    An RF source of any frequency can overload the front end of a sensitive receiver rendering it useless for its intended purpose even if it is tuned to another band. In order to guarantee that they can block cellphone signals they need to use substantial amounts of RF power with a wide bandwidth. There are at least two different blocks of cellphone frequencies and parts of them are adjacent to existing amateur radio frequencies. The amount of power required to jam signals is probably not known with any precision so they will use as much power as they can generate.

    Still I want to know. If existing law is set aside for these putative cellphone jammers who will I need to complain to when I am interfered with? Who will hold them accountable for their actions? Sadly, the short answer is that I may as well howl at the wind if they and their lobbyists get their way.
     
  20. HarveyH42

    Active Member

    Jul 22, 2007
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    But if a cell phone doesn't interfere with with your receiver, I wouldn't think a jammer inside a concrete and steel building would need to be much more powerful. I'm not a cell phone fan. I don't get how so many people find these gadgets crucial to survival on a daily bases. I can understand sometimes they are handy and useful, but mostly they are used to chit-chat. $50-$300 a month, for little more than a toy...

    Can't the jamming be accomplish, without using a stronger signal? Over powering a wide bandwidth might be the simplest, most direct, but there must be other approaches to the problem. I'd really like to see some restrictions on where and when cell phones are used, but not if it's going to interfere with other signals. There must be some way to make everybody happy.

    Doesn't the FCC handle those kinds of complaints? Or do they just handle complaints from people with TV interference? The government does what they want. I doubt the law will pass, people with cell phones are too protective of their little toys, and would go for anything that might do them harm. What if your car breaks down near a jail or prison? How are you going to call for help? You are stuck on the side of the road, with murders and sodomizers just on the other side of a chain link fence...
     
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