A Brief Look at Mobile Phone Jammers

Do you remember how many times you were in the bus that takes you to work and back home every day and you were obligated all the course to listen annoying, never-ending phone discussions of the others sitting near you?
Were you ever almost going nuts while hearing things that you really didn’t care about, and that jammed your calm and concentrated thoughts?
Oh yes you felt like this I’m sure, and you also did think about how to stop them but you didn’t know how.
Well, it is not about “how?” but it’s about “with what?”.


And it is very simple just that you have to be conscious that you have to pass the legal limit in order to do that, with the risk to pay about $11,000 fine (in US) if you are caught doing that.
So, those with fragile nerves, could take a trip to China and there you will easily find the device you need to stop those calls.
It is called a cell phone jammer and it is extremely cheap in China.
You can buy one at just $55 there.

A cell phone jammer looks exactly like a little box at the size of a Kent cigarette pack and it can do a lot.
It sends out radio weaves strong enough to disrupt the phone signal within a radius of up to 10 meters, and if you are willing to pay a little more money on a stronger device you will be sure that next time you are in the train traveling, you will be able to knock out the whole train.


It is true that there is a large number of people that already have these devices and use them when they like, but those that bring these from countries like China, where the law applies rarely, are keeping it secret and not even their close friends don’t know about it.
The UK’s communications regulator, Ofcom, explains why these jammers are considered illegal: they not only break the human rights but also “cause deliberate interference to the radio spectrum which can cause a nuisance to other users and at worst are dangerous – potentially jamming the frequencies used by the emergency and safety-of-life services.”


And now I want to bring into your attention the serious face of these actions.
Although it is perfect to be able to call who you want at any moment from anywhere but in large public places like restaurants, concert halls, movie theaters, shopping malls and especially churches people are affected negatively if they hear long phone calls and that’s because few have common sense to respect the others around.


A mobile phone communicates with its service network through a tower or a base station and these towers are dividing a town into smaller areas or cells. While the mobile phone’s signal is handed from tower to tower as the user drives down the street, the jamming device can transmit on the same radio frequencies as the phone, disrupting this way the communication between the phone and the base station in the tower.
This action is called a denial-of-service attack meaning that the jammer is denying the service of the radio spectrum to the mobile phone users within the range of the jamming device, by overpowering the phone after transmitting the signal on the same frequency and at a high-enough power so that the 2 signals collide and cancel each other out.


A jamming device consists of an antenna for sending the signal, the circuitry (voltage-controlled oscillator, tuning circuit, noise generator and RF amplification) and the power supply (battery).


Who invented this device designed it to interrupt criminals’ and terrorists’ communications, so it won’t happen again like in 2004 when the trains in Spain were blew up with the help of mobile phones that triggered the explosives.