How to Fight a Mobile Phone GSM Jammer/Blocker

I have three ideas, two require you to get equipment, I know nothing about software but that doesn't mean it doesn't exist, it just means I don't know about it.

1. The easiest way is go somewhere that isn't close to the jammer, or get the jammer turned off, depending on what country it is it may be illegal anyhow.

2. Get a directional antenna and a cable to connect it to your cell phone, point the antenna at the closest cell tower.

3. Since you have internet access, get a picocell for the area you intend to use your phone.

good luck.

Dear Sir,

Thankyou for your response, please tell me more about PICO CELL.

How iam able to connect with the base station via PICO CELL?

Is PICO CELL is some kind of Mobile booster device

Use a land-line or HAM or sat phone, get off the jammed frequency.

Your post lacks some information. Is this happening in your house or place of work only or is it happening everywhere? If it's happening everywhere then the problem is not a jammer but in your phone.

If it's happening at home, you can report it to the authorities and have them trace the jammer and arrest him (if it's illegal in your country. if it's not illegal, you're stuck).

If it's happening at work, your company may have a policy against cell phone use while at work (this is possible. in the factory where i work, cell phones are not allowed). Instead of having the employees turn in their cell phone, the company just jams them. This could also be possible in places like restaurants or movie houses.

Please give additional information so that we can give you better answers.

Don't forget that cell phones can be infected with viruses also.

regards,

Vulcan

Yeah...where are you having the problems? In a theatre, or in the mall outside of the theatre?

Dear All,

I have faced this problem only at work, actually it (JAMMER) is implemented for production unit but unfortunately my caben is adjacent to Knitting Production Area so iam unable to attend my important fone calls at work.

you said:

"iam unable to attend my important fone calls at work"

Let us understand, you are working for this mill/plant, whatever it is, but you get 'Important" phone calls at work?.

What might these be?, your wife telling you to bring home milk?, or your buddies asking you to meet them after work for some fun?, or, maybe your drug dealer telling you the "Good Shit" just came in..

If it's REALLY important, like an emergency at home, I suppose the factory land lines still work...

Damn cell phones, I don't think they should be allowed in a work place.. What between employees just playing games on their computer, or worse surfin the net for porn, and just plain wasting the employers time by chatting endlessly on their dang cell phone, no wonder our world is in trouble, and quality production is down the drain.

It's Not only the big money boys that are screwing us, it's also the workers that are screwing the employers..

We need to start another blog about nightmare employees, I could further to that.

Donald

You may use this as leverage for a more conducive office location or closer to the bathroom

There now. One single piece of additional information (happens only at work) makes things a bit clearer and we can give better answers. Unfortunately, better answers do not necessarily mean you will like them.

If your place of work has installed a jammer, it has done so for a reason. You may try to plead your case with management but I don't think you will get very far with it.

Does your cabin (I suppose you mean office) have a landline (ordinary phone)? If so, just tell your friends or relatives to call you on your local number instead of your cell phone while you're at work.

Alternatively, most networks have a call divert feature. When you're at work, activate your call divert so that all calls to your cell phone will be directed to your office phone. You need not miss any "important" calls. Then, when you go home, deactivate the call divert feature.

regards,

Vulcan

"Alternatively, most networks have a call divert feature. When you're at work, activate your call divert so that all calls to your cell phone will be directed to your office phone."

where is the divert function stored, in the provider's server, or in owner's phone?

if at the provider's server, this'll work. otherwise, not.

The function is activated by the network upon request by the owner's phone. When I activate call divert, my phone tells me that it's sending the request to the server. The phone merely sends the request to the server along with the phone number to divert the call. At least that's how I think it works.

If there's anyone out there working in a cell phone company and knows how this works, I'd appreciate a better explanation.

It's easy to find out if you have that feature. In my Nokia 2760, I select Menu/Settings/Call/Call Divert. Then it has a set of selections:

• Divert All Voice Calls
• Divert If Busy
• Divert If Not Answered
• Divert If Out Of Reach
• Divert If Not Available
• Divert All Fax Calls
• Cancel All Diverts

If I select "Divert All Voice Calls", it asks me whether I want to activate it, cancel it or check the status.

I think this would be the best solution for this particular problem...other than finding work where cell phone use is allowed.

regards,

Vulcan

I was surprised to see that a Google search turned up NOTHING that hasn't already been covered already in this posting! Oh, well. We always knew we were smart.

In a cellular network, all incoming calls go through a Home Location Register (HLR). The HLR is the network element that knows where the phone is so that incoming calls can be appropriately routed. It also knows what services are provisioned for the subscription so that it can be properly billed.

So, if your cell service provider offers call forwarding (most do), you basically have the ability to provide instructions to the HLR on how to handle incoming calls. Generally, this is to forward all calls, forward calls if busy, forward calls if no answer, etc. If no instructions are given, the call is routed to the cell phone. If you have selected call forwarding, these instructions and the number to receive the forwarded call are placed in a table in the HLR. These values remain in place as long as you, the subscriber, want.

The HLR gives instructions to the mobile switching center (the cell service equivalent of a central office) to route the call to the cell phone or, if instructions have been given to the HLR, to forward to a specified number. This number is in a table in the HLR. When you select to have calls forwarded, you have to provide a number to forward them to. The HLR and the MSC then route the incoming call appropriately. The communication between the HLR and the MSC,and the MSC and whatever networks it needs to route the call to, are done via SS7 protocol.

The other reason the HLR is involved deals with billing. I can't speak for all service providers, but the one I work for charges for call forwarding. If you ever do want to use the service, make sure you know whether or not your service provider charges and how much. Since the service is based in the network, it is usually available for all subscribers -- but it usually isn't available for free.

Thanks for the clarification bp01.

Yes, the service provider usually charges for call forwarding (or diverting, whatever). In the Philippines, calling from a cellphone to a landline is more expensive than cell phone to cell phone. If I divert from my cell to a landline, I get charged for the cell to landline call.

However, if I need to stay in contact with my family, I think it's a small price to pay.

regards,

Vulcan

Well then, have you tried just asking the company to turn the jammer off? You might have legal recourse you know.

I have to chime in and agree with the others on this post. If the company has installed a jammer. you are stuck. Your only recourse is to work with the company, especially if the jammer is legal. If it isn't legal, you might have legal recourse as Yusef1 points out, but that could jeopardize your employment.

If you do try to work with the company, here are some points to consider:

• Is this your personal cell phone or one provided by the company?
• Is the cell phone necessary for worK?
• What alternatives do you have for work related communication? Several people have mentioned land lines, for example. Are they available?
• Is the factory your normal work place or are you in a position, such as sales, where you spend much of your time away from the plant, but are required to come in periodically?

Anyway, when you have answered those questions, you will be in a position to approach your management about some sort of solution. My guess is that you won't get far in that they will not be willing to make an exception just for you.

There are only two ways to defeat the jammer:

1. Render it ineffective -- which means everyone else can use the airwaves, not just you. Management probably wouldn't like that.
2. Transmit at a power level higher than the jammer. Your cell phone can't transmit a signal strong enough to overcome the jammers. Even if it could, you'd likely cause some sort of damage to yourself.

Could over power jammer if hardwire cell phone antenna directly to ethernet

Damn, I wish I had one of those jammers.

As a matter of fact, I wish every car had one built in to it that came on when the ignition was turned on. Some lady almost nailed me last month when yaking into her cell phone and started merging into my lane. Destroys your peripheral vision on the phone side.

Jammers are being used to prevent cell phone use to detonate IEDs. Where do YOU live?

you're so right.

in the UAE, it's being actively prohibited by stiff fines. what with 1 road death per day!

in fact, it's a pretty good idea. phones jammed while engine is on!

Kyoto, I am sure there are a lot of people who would love to be able to defeat a jammer, certainly anybody who wants to use a cell phone for something other than its approved purpose as in your example. I have never heard of anybody using a jammer as a form of public mischief like graffitti. (Of coure, now that I have said that...grin!) They are used to keep silence in theatres, to send groups of teens packing in shopping malls, and of course, the military uses them all the time, and not just to prevent IED's from being detonated, but for social oppression...disrupting co-ordinated riots, and so forth. (The Oka crisis was pretty much quelled when the military jammed all communication. No story, the press went elsewhere. The protest died on the vine.) All in all, I believe that to try to defeat the big boys and their jammers, though possibly great fun, AND an excellent exercise of the power of the people, the stakes would be high, and remember, the "Powers That Be" have no sense of humour.

Of course, even if you are jammed, you can still take a picture. Case in point, the RCMP tasering that fellow to death in the Vancover airport a couple months ago. Without cell phone pictures, taken in a part of the airport where you are not supposed to use cell phones (jammed area? not sure.) they might have got away with something which looks suspiciously like something very nasty. As it is, they are now facing a public inquirey in which they now have to explain themselves. Like the Rodney King story did, this should lead to a light being shed on the dark side.

Interestingly enough, there has been talk of installing jammers on highways to prevent such accidents. However, these ideas usually fall flat when it is pointed out that people need cell phones to call a breakdown wagon, or for that matter, to call for help when on the highway. An appeal to basic human decency would work better than a cell phone jammer on every automobile. (A police friend of mine noted once that he would like to see a disable unit on every car so that he could "zap" the car and turn off its engine before they took off on high speed chases...a concept which I find disturbing, and I am not quite sure why. Might that not be better than the methods in use now? Hmmmm.... sounds like a blog topic to me! But an electronic way to jam an automobile is off topic here, on this thread, which is, of course, about jamming cell phones.)

Yes I think you can text even when jammed too.

That Zap as your friend described stopping a high speed pursuit is a capability in some of Europe

Wow, that surely confuses me. If jamming is killing your ability to transmit/receive, how could you text? Well, I guess you could type away and the characters appear on you little screen but I could be surprised if they could manage to escape that little bugger into the ether.

I can't explain it either but it will work sometimes

That's interesting. Since everything to/from a cell phone has to travel over the radio, blocking should eliminate all traffic.

The only way(s) that I could see this happening are:

1. The jammer is ineffective.
2. The GSM carrier transmits data and/or signalling traffic over a different (unblocked) channel than voice traffic.
3. Jamming is basically blocking a particular signal in a particular area. If the cell phone can "see" a cell tower in a different direction, it might work. In the diagram below, the cell phone couldn't communicate with the tower on the left as it is being blocked/jammed; however, it may be able to get a signal from the tower on the right. This is pretty speculative because if the phone could "see" the tower, it would probably be able to send voice traffic as well.

To understand it you have to know how the jammer works.

As far as I know, a jammer's effect is on the receiver. No meaningful data (or sound of speech or other signal) can be received on your phone or radio when it is jammed: I would be surprised if you can receive a text message either.

BUT you may be able to transmit a message, if as I believe is the case, the jammer is targeting receivers in its range with a load of interference signals, rather than targeting transmissions or transmitters.

AFAIK, SMS is handled by another channel/server by the provider, and is data transmission, not voice transmission.

I guess I thinking the jammer was broadband; jamming all frequencies.

http://en.wikipedia.org/wiki/Radio_jamming

To use cell phone in public places ignoring others' feeling is totally immoral and ridiculous. It should be banned in some certain sites as from my point of view. I'd like to recommend the gov. to install cell phone jammers in some certain public places.
But for now I just bought a cell phone jammer for my own use from http://www.jammerall.com/ , it helps really much when I feel fed up with the cell phone noise.

yes you are right