How dependent are you on your cell phone? We guessed right if your answer is ‘very dependent’. It is a fact that cell phones have become a necessity today—we’d gather a crowd of cynics if we said that cell phones will stop working in the future. But on second thoughts, there might be some truth to it. Let’s marinate on that and go back to the inception of mobile technology.
The cell phone fad hit the Indian market like lightning on a vulnerable night. The best part—for most of us—is that, it stayed, it grew and it has now engulfed us like a bush fire. Today cell phones are arguably a style statement but undoubtedly a necessity for convenient communication. But there are times when it becomes important not to be able to use a cell phone. Before delving into this situation, let’s go through a primer on cell phone technology.
‘E.T. phone home’
Did you know that the cell phones use the same principles as a radio? Well partially they do. We’re not talking about the internal FM radio in your phone that you use to hear music. Cell phones work roughly like walkie-talkies that you must have used in your adolescent years—the major difference being their need to communicate with a ‘base station’ instead of directly with each other. Also, walkie-talkies are half-duplex devices that transmit and receive at one particular frequency, while cell phones are full-duplex devices that use two separate frequencies simultaneously. Cell phones, better known as mobile phones, are 2-way radios that interchange radio signals with the base stations of the network provider (for example, Hutch or Airtel in Mumbai). The radios we use for listening to music also operate using radio waves, but those frequencies are very low, for example 98.3 MHz. In some phones, if you open the back panel (battery compartment) you’ll notice the frequencies (eg, 900 MHz) at which the phone can be operated. These frequencies are clearly much higher than our radio sets. Lower frequencies are used in several other applications such as aircraft communications and higher frequencies in microwave ovens. So this explains why we are refrained from using cell phones and electronic devices on a flight.
No brain-chewing
Picture yourself in a restaurant or in a library or any of those quiet places. There is this person next to you who is engrossed in a high-decibel conversation right in your face. This can be painfully brain-chewing. So what do you do? In a dire situation like this, using a device known as a cell phone jammer could bring you immediate salvation. Besides the fact that it’s illegal, using one can get you in trouble especially if you’re trying to play a prank. Although illegal in many countries like the United States, there are people who use hand-held cell phone jammers in other parts of the world. So before buying or using one, it is strongly recommended to check on it on the legal front. More on how this device works later on.
‘Let’s JAM it’
Shockingly, cell phones are being used to do a lot more than just make or receive calls and text messages (SMS etc). If you have seen the movie ‘The Jackal’, you’ll know exactly what we’re talking about. Here, Bruce Willis (the jackal) uses a cell phone to control his radio controlled sniper gun hidden in a vehicle yards away.
On a serious note: Assuming that you’ve been watching the news lately, the Mumbai train blasts are alleged to have involved cell phone triggers to set off the explosives. Check out the ‘In The News’ box to know more. But guess what—if a cell phone was the cause, then a jammer could have saved the day.
Jammers are powerful and intricate devices, but unfortunately not too many people might know much about them. So let’s dive deeper and resurrect this potential savior.
Jammers! Say what?
Jammers are radio frequency transmitters that block radio communication between devices—in this case a cell phone. They simply disable the cell phone from making or receiving voice or data calls and messaging by preventing cellular signals from reaching it. There are different types and sizes of jammers depending on their power and coverage range. Most hand held jammers look like normal cell phones and they use cell phone batteries. Larger jammers can be as big as a briefcase and can be used with a normal power outlet.
Jammers were mainly intended for military operations to track terrorist activities by disrupting their radio communication. Although they were introduced for law enforcement, they are increasingly being incorporated in other civilian areas of use.
How does it work?
A cell phone uses two separate frequencies; one is used for transmitting (talking) and the other for receiving (hearing). The signal originating from one phone is sent to the base station and from where it is relayed to the recipient. When a cell phone comes into the range of an active jammer, the signals originating from the cell phone collide with the signals of the jammer. This effectively cancels out the phone signals. Most jammers cancel one frequency of the cell phone which does the trick. Since one signal gets cancelled, the phone interprets that there is no network and hence stops functioning. In the case of rather sophisticated jammers, all the signals that the phone can receive get cancelled. This ensures that the phone does not receive an open signal to work with.
In the near future, if you’d like to stop the usage of cellular phones at your office or your home, you’d need to simply paint it. A company called NaturalNano Inc, is in the process and development of a special type of paint that uses halloysite nanotubes coated with copper. This special paint, when applied to the exterior of a room or an enclosure might be able to block radio waves at particular frequencies, and this inlcudes cell phone signals. Other variants of this technology would also enable it to hamper the reception of WiFi communications and other electronic devices dependant on radio communication.
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