-
Design And Construction Of A Remote Controlled Tri–band Frequency Jammer.
CHAPTER TWO -- [Total Page(s) 3]
Page 3 of 3
-
-
-
2.4 THEORETICAL FRAMEWORK
2.4.1 JAMMING TECHNIQUES
There are three most common important techniques to jam a RF device:
1. Spoofing - in this method the mobile phone is been detected and the jamming device sends asignal to disable the mobile phone or sends a message to the user of that phone to switch it to the silent mode.
2. Shielding attacks - this is Electromagnetic Field (EMF) shielding of the mobile phone signalin which phone cannot transmit or receive any RF signal from outside.
3. Daniel of service (DOS) - in this technique the device transmits a noise signal at the sameoperating frequency of mobile phone in order to decrease the SNR of the mobile. This is the simplest technique and is very common
The design that will be used in this project shall be the Denial of Service (DoS) technique which transmit noise on the same frequency on the Global System of Mobile communication (GSM) 1800MHz (known also as the DCS 1800 band)
2.4.2 JAMMING TO SIGNAL RATIO
The jamming to signal noise ratio which is when usability is denied and the error rate of the transmission cannot be compensated by error correction. A successful attack requires that the jammer power is roughly equal to the signal power of the receiver, that is, the mobile device. The effect of jamming signal depends upon J/S (Jamming to Signal ratio), interleaving, modulation type, channel coding technique of the target system.
The Jamming to Signal ratio is giving by:
where
Pj = RF Jammer Power
Pt = Transmitter Power
Gjr =Antenna gain from jammer to the receiver
Grj = Antenna gain from receiver to the jammer
Gtr = Antenna gain from transmitter to the receiver
Grt = Antenna gain from receiver to the transmitter
Rjr = Range between jammer and communication receiver
Rtr = Range between communication transmitter and receiver
Lj = Jammer signal loss, this includes polarization loss
Lr = Communication signal loss
Bj = Jamming transmitter bandwidth
Br = Communication receiver bandwidth
The signal to noise ratio (SNR) with a minimum value of 9dB will be used as worst case scenario for the jammer, the maximum power output at the mobile device is -15bBm. The above equation indicates that the jammer Effective Radiated Power which is the product of antenna gain and output power, should be high if jamming efficiency is required.
In conclusion, Jamming is effective when the jamming signal repudiates the usability of the communication broadcast. In digital communications, the efficacy is repudiated when the error level of the broadcast cannot be recompensed by error correction. Usually, an effective jamming attack necessitates that the jammer power is approximately equal to signal power at the receiver (mobile device).
CHAPTER TWO -- [Total Page(s) 3]
Page 3 of 3
-
-
ABSRACT - [ Total Page(s): 1 ]ABSTRACT COMING SOON ... Continue reading---
APPENDIX A - [ Total Page(s): 1 ]APPENDIX AList of Components• Vero Board • Connecting wire • Power Switch • 30 Amps Fuse • Soldering Lead • Soldering Iron • LEDs • 240V/ 60V Transformer • 12 volts D.C battery • • IN9004, IN4004.1 diode, • 750 Ω, 750.1Ω, 100Ω, 1KΩ, 2KΩ, 22KΩ, 100KΩ, 1KΩ, 2KΩ, 22kΩ resistors • 555 timer • ... Continue reading---
APPENDIX B - [ Total Page(s): 2 ] ... Continue reading---
CHAPTER ONE - [ Total Page(s): 2 ]CHAPTER ONEINTRODUCTION1.1 BACKGROUND OF THE STUDYA mobile phone jammer or signal blocker is an instrument used to prevent cellular phones from receiving signals from base stations. The process of blocking the receiver to receive a transmitted signal is called Jamming of the signal. The jammer effectively disallows cellular phone signal when activated. These devices can be used in practically any location, but are found primarily in places where a phone call would be particularly disruptiv ... Continue reading---
CHAPTER THREE - [ Total Page(s): 11 ]The operation of power supply is as shown:The transformer which transforms 220V AC to other levels of voltages. Its functions are outlined below:i. Rectification: Convert the AC voltage to DC voltage.ii. Filtering: “Eliminate the noise†so that a constant DC voltage is produced. This filter is just alarge capacitor used to minimize the ripple in the output.iii. Voltage Regulation: It provides the desired DC voltage.The step down transformer steps down the input volt ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 5 ]The bar chart in figure 4.9 above shows the jamming strength of the jammer at Eigbejila, Odota and Garin Alimi area of Ilorin west Local government area kwara State, Nigeria. It is obvious from table 4.2 above that as the distance between the cell phone and the base station increases, the effective jamming distance increases. This is due to the fact that the amount of power reaching the cell phone from the base station decreases as the cell phone moves farther from the base station and vice ve ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVECONCLUSION, CHALLENGES, RECOMMENDATION 5.1 ConclusionsThis project is very useful for mobile phones restricted places such as private meetings, examination hall, defense establishments, military camp, Hospitals; Petrol pumps, Libraries etc. This device can scramble/jam mobile devices in a given area within the operating frequency range of 800MHz - 2100MHz at the range of 2-7 meters. The designed device works in Tri-band. It jams the GSM 800 band, GSM 1800 band and the add ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCES1. Science Journal of Physics ISSN: 2276-6367 http://www.sjpub.org/sjp.html.2. Radio Jamming", Wikipedia Foundation, Inc. 2012. 3. "Electronic Warfare", Wikipedia Foundation, Inc. 2012. 4. "Electronic Counter-Countermeasures", Wikipedia Foundation, Inc. 2012. 5. Scourias, John (1997): Overview of the Global System for Mobile Communications, University of Waterloo.6. "Mobile Phone Jammers", Wikipedia Foundation, Inc. 2012.7. Semiconductor device ... Continue reading---
