CONSTRUCTION OF RADIO FREQUENCY GSM SIGNAL JAMMER

CHAPTER ONE

INTRODUCTION

1.1 Introduction

A wireless signal jammer is a device which blocks transmission by creating interference. This wireless signal jammer can be categorized into the Radio Frequency RF jammer and GSM jammer.

A Radio Frequency jammer is a device used to disrupt or prevent communication via a broadcasted RF signal. It is an RF and GSM frequency disrupter commonly known as wideband radio frequency RF and GSM cell phone jammer. Simultaneously, they can blocks all commercial FM broadcast band 87.5 MHz to 108 MHz and GSM signal transmissions within the jammers transmission range. The device can possibly block these frequencies by transmitting a dirty signal like noise on the same frequency at which the GSM and radio system operates.

A Radio Frequency jammer is a device that transmits a radio frequency signal on the same frequency at which the radio system operates and the jamming succeeds when the radio sets in the area where the jammer is located are disabled.

A GSM jammer is a device that transmits a signal on the same frequency at which the GSM operates. The jamming succeeds when the mobile phones in the area where the jammer is located are disabled.

In recent times, where bombs are being planted and detonated by GSM or Radio Frequency signals, this device can be at an advantage by jamming the signals required for the detonation of the bomb.

The solution to these annoying and disrupting noises is to install a device which can block the signal transmission from mobile phones and radio sets and thus, disrupt the triggering of bombs by these wireless signals.

1.2 Project Background

The technology being used by this device is very simple. The mobile phone transmission is being blocked and interfered by RF which creates high noise. The frequency being generated by the jamming device jams the signal being generated by the cell tower as illustrated in figure 1.1 below. When the signal has been blocked, the mobile phone will show NO NETWORK on the network bar, and radio devices will not be able to tune into any signal. Thus, all phones and radio devices in the 200m radius of the jammer will be having the same situation.

Radio Frequency RF and Mobile signal jammer is an illegal device in many countries. It is because the device is blocking the signal which has been approved by government agency as a legal communication transmission system. According to the National Communications Commission NCC in Nigeria, The manufacture, importation, sale, or offer for sale, of devices designed to block or jam wireless transmission is prohibited.

As shown in Fig. 1.1 below, the wireless signal jammer is divided into two major branches: the GSM signal jammer, and the radio receiver jammer. The radio receiver jammer is also subdivided into the Amplitude Modulated AM signal jammer and the Frequency Modulated FM Signal jammer. The Cell phones and Radio receivers cannot be blocked simultaneously as they operate at separate frequencies. The frequency can then be varied using a frequency tuner mounted on the jammer

Fig. 1.1 Block Diagram of Signal Jammer

The block diagram in Fig. 1.2 below gives a pictorial representation of the working principle of a wireless signal jammer

Fig. 1.2: Pictorial Representation of a Radio Frequency Jammer

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From the Fig. 1.2, the jamming device jams cell phones and radio sets within the range of cell towers 1 and 2.

The cell tower 1, 2, 3 and 4 transmits signals which can be received by GSM or radio sets. The jamming device is placed inbetween cell towers 1 and 2 and thus produces a signal which is at the same frequency being operated /transmitted by the cell tower. It can be said that the resultant of the signals is zero.

From Fig. 1.2, the sending object is the jamming device and the target object is the cell towers.

1.3 Problem Statement

Due to the increasing sophistication and high technology, most people are using mobile phones, and also due to the need for man to stay updated with his environment, the use of radio is also in wide use.

Mobile phones have become a very important communication tool today. With the use of the mobile phones everywhere, it becomes annoying device while working, studying, praying and many more.

Modern technology has contributed to the sophistication of bombs which are being triggered by GSM and Radio signals.

Wireless mobile jammer can be placed in schools, mosque, and conference hall, meeting rooms, library and many more places which need quiet and peaceful environment. This device will block the transmission of Radio and GSM signals.

1.4 Objectives

The Development of Wireless Signal Jammer for Security Application objective is:

To design Radio Frequency RF, Intermediate Frequency IF, and Power Supply circuit. To construct the Development of Wireless Signal Jammer for Security Applications circuit.

To construct the development of wireless signal jammer for security applications circuit.

To simulate Intermediate Frequency IF section circuit.

To block mobile phones transmission by creating interference.

To block amplitude modulated and frequency modulated signal transmission by creating interference within its range.

1.5 Scope of Project /Limitation

This project only focuses on blocking the signal transmission of GSM900 which is the range between 935 to 960 MHz. This is because the components are hard to find in Nigeria for the GSM1800 frequency range between 1805 to 1880 MHz The components for GSM1800 are also very expensive compared to GSM900.

The second limitations of the project are, the device only can block the three main operators which are ETISALAT, MTN and GLOBACOM. This is because, the lines are only for Nigerian users and the frequency band range is between 935 to 960 MHz. These requirements fulfil the GSM900 specifications.

The third limitation is that for reliability of the jammer, a Radio Frequency amplifier should be incorporated but the components required for this are difficult to find in Nigeria.

1.6 Summary

This project is mainly intended to prevent the usage of mobile phones in places inside it coverage without interfering with communication channels outside it range, thus providing a cheap and reliable method for blocking mobile communication in the required restricted area only. Although we must be aware of the fact that nowadays lot of mobile phones can easily negotiate the jammer effect are available and therefore advance measures should be taken to jam such type of devices. The main disadvantage of the mobile phone jammer is that the transmission of the jamming signal is prohibited by law in many countries. These disadvantages will restrict the use of Radio Frequency jammer