Film-Tech Forum ARCHIVE: Cell phone jammer

This is topic Cell phone jammer in forum Film-Yak at Film-Tech Forum ARCHIVE.

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Posted by Jack Ondracek (Member # 1466) on 12-21-2002, 03:45 PM:

Has anyone noted the Israeli products that are supposed to jam cell phones within a limited range? They apparently are not legal in the States, but I'm wondering if there's an "underground" market for this kind of stuff. Has anyone ever seen/used/been affected by one of these in a theatre? Seems like an obvious application.

How about any efforts to legalize this kind of technology over here?.. or do the cell companies have too much of a lock on it? Last I saw, they were using arguments like "a person couldn't call 911 (from inside a theatre?) if jammers were allowed."

Just curious.

Posted by Greg Mueller (Member # 17) on 12-21-2002, 05:49 PM:

Great idea.
How would they know if they had a "jammed" cell phone or just couldn't get survice. I don't believe the cell service providers guarantee service, do they?
Maybe you could use a small yagi antenna to make the jamming directional.
I love it

Posted by John Walsh (Member # 168) on 12-21-2002, 11:52 PM:

We actually just went through this. It is illegal to block cell phone reception in the US. This is because companies (Sprint, Verizon, etc.) lease frequency 'space' and it is theirs to use. If you operate a cell phone jammer, you are infringing on their part of the spectrum. It does not matter if you own the property. A jammer can not even be shipped to the US.

Posted by Steve Kraus (Member # 476) on 12-22-2002, 01:16 AM:

No, it's illegal to operate an unlicensed transmitter on those (and most) frequencies which is what a jammer is. No law against passively blocking reception if there is a way to do that. Faraday cage techniques perhaps?

Posted by Dennis Benjamin (Member # 1137) on 12-22-2002, 02:03 PM:

Actually, when I worked for Muvico Theatres, we tested these for the Government. At the Muvico Paradise 24 we tested them for one week as part of a government survey.They worked pretty well. However, there are legal ramifications - as previously stated.Not to mention the biggest aspect of it - doctors, policemen, and government agents who need to have their cell on them for emergencies. The FCC was the group that was testing the units. The test went very well - but we will never see them in movie theatres.

Posted by Jeffry L. Johnson (Member # 453) on 12-22-2002, 02:20 PM:

Check the Ground Level forum. I just bumped a thread on this topic.

Posted by Jason Black (Member # 684) on 12-22-2002, 07:58 PM:

Ya know, the more I think about it the stronger I feel about this situation.

If someone is soooo damn important that they must have mobile tracking device on them 24/7, they shouldn't be in a theatre in the first place! Public yakkers on cell phones just plain piss me off! I hate being next to "that guy/girl" who has to tell their phonemate what's going on in their life while at the register trying to pay (all while holding up the line and pissing everyone else off). And, invariably, that person looks at everyone else as if to say "What? what are you looking at?"

I admit, I carry my cell nearly everywhere, but I will not take a call while in a public place in view/earshot of others. It's plain rude and tasteless. Plus, what business is it of anyone else's what I'm talking about?

Cell phones should be able to be blocked in actual auditoriums. I think people have been numbed enough to allow them in common areas like the lobby, restrooms, etc. but be damned if they should have to pay to listen to some jerk yakking in during the presentation!

Posted by Jack Ondracek (Member # 1466) on 12-22-2002, 08:19 PM:

Well, I did some more looking around & found a lot more articles about these things. Since the last time I looked, a US-based advocacy group has kicked in, and most media "sound bytes" seem to track back to this group and its spokesman. While other countries have found ways to make use of these things without major problems, they haven't been legalized in the 'states... and this group is pretty sure they won't be.

As with all things political, this group has found a narrow, single-minded hook to push continued banning of cell jammers. The idea that people need to be able to make and receive emergency calls, even in a hostile environment like a theatre.

The fact that theatres have wired phones doesn't matter to them. As for emergency personnel, firemen don't use cell phones to alert them, and unless they've stopped, doctors used to have pagers... which would not be affected by a cell jammer. It seems a pretty thin argument, since legal passive devices would cause the same effect, and nobody's really griping muchy about the risk to life and limb caused by that technology.

One article had it right on, as far as I can tell. The cell phone industry has spent billions in this country to get control of spectrum. In light of technological offerings that lag behind countries like Japan, competition from other cell companies and a sluggish market caused in part by overbuilding, the last thing these companies want to see is technology that prevents their customers from using as much billable airtime as possible. If one industry could get a toe-hold in, like theatres, schools, hospitals, airlines, etc... the rest would probably follow pretty quickly.

Another thing that seems interesting is that there appears to be a pretty healthy underground market in these things. Tracking their use is difficult because the users don't seem to be able to tell the difference between passive or active jamming, and therefore do not file complaints with the FCC, which admits to not having ever raided an illegal jamming site.

There was an article that mentioned technology that would allow an outside signal to put nearby cell phones into vibrate mode, but it said that few manufacturers had been inclined to add it to their products.

What we need is Maxwell Smart's "cone of silence"!! [thumbsup]

Posted by Dave Macaulay (Member # 813) on 12-22-2002, 09:44 PM:

Interesting teaser story about a cell phone blocking product:
http://www.popsci.com/popsci/computers/article/0,12543,356706,00.html
Would this affect pagers as well? radio mics?

Posted by Jack Ondracek (Member # 1466) on 12-22-2002, 10:07 PM:

quote:
From David McC...
Would this affect pagers as well? radio mics?

As they describe the panels, some pagers could be affected... probably ones that run in the 900 meg range. Pagers that run on frequencies between around 31 megs up to the 450 meg UHF bands probably would be OK.

Most wireless mics I've seen ran on frequencies between 49 megs and 450. If they're putting them into the 900 meg bands and you tried one in a room with this "microwave absorbing" stuff in the walls, you might not be able to put the mic and receiver in different rooms without losing the signal. You probably could run them in the same room, though.

Posted by Gordon McLeod (Member # 33) on 12-22-2002, 11:12 PM:

Well I for one are infavor of blocking them in public places A policemens/ doctors right for emergancy calls is frankly less important than my enjoyment of the entertainment I paid for. If they are on call then stay at home they are being paid to be on call
Actually there may be a test case over air right coming up in canada that the government doesn't own air rights over private property

Posted by Jack Ondracek (Member # 1466) on 12-23-2002, 05:33 AM:

quote:
... from Gordon McL:
...Actually there may be a test case over air right coming up in canada that the government doesn't own air rights over private property.

That will be interesting.
We apparently can install passive devices to flummox a cell phone. We also appear to be quite capable of running enough fluorescent lights and computerized equipment to render most AM radios useless in many buildings... but we can't legally run active devices to keep cell phones at bay. [Roll Eyes]

Posted by Mark J. Marshall (Member # 1409) on 12-23-2002, 08:24 AM:

I love the one that looks like a cell phone. [Smile]

Posted by Greg Mueller (Member # 17) on 12-23-2002, 09:26 AM:

I have a friend who is a cardiologist and is on call constantly. He gave up on cell phones and went back to his pager because the phone was so unreliable. (even in good reception areas) My opinion would be that the people who are using the doctor/fireman excuse as an argument are somehow tied and/or funded by the cell phone companies (geez I'm starting to sound like Charlie Everett)

Posted by Jonathan Worthing (Member # 803) on 12-23-2002, 09:34 AM:

The reason they are banned are that they can interfere with electronic devices like Hearing aids & more importantly Pace Makers.

There is a on the wall detector that I looked in to a few years ago that was a passive system that detected a Cell phone.

This can be switched to a sign that flashes TURN OFF YOUR PHONE in red neon.

The system is in use in some UK Hospitals where it is required to turn phones off.

Posted by Scott Norwood (Member # 30) on 12-23-2002, 11:58 AM:

I think Jonathan just hit on a great idea: set up one of those "phone detector" thingies in the theatre and connect it to a relay which will turn on a slide projector to show a "turn off your phone" slide on the screen (superimposed with the movie). To be really evil, one could also have a CD player or cart machine wired into non-sync to play some nasty message.

Posted by Greg Mueller (Member # 17) on 12-23-2002, 06:07 PM:

Yah but if you did that everyone would have to suffer, looking at that message on the screen.
I say a megawatt laser with cell phone homing device. Key up on your cell phone....zap!
Or maybe just a big spot light with homing device.

Posted by Jonathan Worthing (Member # 803) on 12-24-2002, 03:31 AM:

Link it to a spray can of fowl smelling spray,you could sniff them out in the dark. [Big Grin]

Posted by Jack Ondracek (Member # 1466) on 12-24-2002, 04:27 PM:

quote:
...from Greg Mueller:
I say a megawatt laser with cell phone homing device. Key up on your cell phone....zap!

Ironic that you should mention the use of lasers in a cell-phone deterrent. Seeding a prospective market, maybe??? [Big Grin]

Oh... try not to destroy the seats when incinerating the offending phone user, please!!

Posted by Leo Enticknap (Member # 534) on 12-26-2002, 10:57 AM:

This really boils down to a social issue as distinct from a technological issue. I know I've mentioned this before, but I'm still struck by the so-called 'quiet coaches' on British trains. This is one carriage on all long-distance trains in which you are not supposed to use a mobile 'phone at all. The notices are almost universally ignored. On occasions when I've asked people to switch their 'phones off in these carriages, their response has ranged from 'Oh, I'm just making a quick call', to something unprintable. Yet no-one lights up in the 'no smoking' carriages. No-one, so far, has managed to explain to me why one rule is respected and the other is ignored.

I'll say now that I hate mobile 'phones - specifically, the idea that you're 'on duty' 24/7 because you carry one - and would cheerfully throw mine off the Tyne Bridge tomorrow if it weren't for the fact that work requires me to have it. But I'm obviously in a small minority. 'No smoking' rules in public places work because 9 out of 10 people agree with the idea. It seems to me that the reverse applies to mobile 'phones, and that if you're going to aim to satisfy the 10% like me who don't like the sound of them ringing and of people screaming into them in public, you'll only be able to do so by enforcing an unpopular rule. The question is, is it worth it?

Posted by Gracia L. Babbidge (Member # 582) on 12-26-2002, 11:13 AM:

If more people that used cellular phones showed more courtesy to the poeple around themselves when they use those annoying little gizmos, it wouldn't be nearly so bad.
And I really wish more people would pull over and STOP driving to talk on their phones - it would make driving a lot safer!

<- does not have or want a cellular phone! [thumbsup]

Posted by Greg Mueller (Member # 17) on 12-26-2002, 11:59 AM:

Gracia
The other day I had actually pulled over on the freeway, and was talking on my cell phone, when a Washington State Patrol trouper walked up to the passenger side of the car. I rolled down the passenger window and said "Thanks for stopping but I'm just making a cell call and didn't want to crash" You should have seen the look on his face. He finally stammered something like "Ok just checking" and walked off. I thought he was going to faint.