|
|
#1
10-11-2006, 01:14 AM
|
|||
|
|||
GSM/Radio Jamming... Theory & Math
If you set up an FM modulation system with the carrier around the same frequancy as the mid GSM(ish) freq, and then modulate that with a sine wave of enough amplitude you should be able to "over modulate" (which may be the wrong choiuce of words as its what you want to do) you should in theory be able to bottom out around the lower GSM limits and go all the way up to the upper limits of the band... I feel some maths coming along...
FM Modulation: http://en.wikipedia.org/wiki/FM Frequancy Deviation: AF Voltage Deviation: AV Rated System Deviation: Fd Frequency Deviation Constant: k, k=AF/Fd Modular Sensitivity: AF/AV Modulation Index: Mf, Mf = AF/Fm = (k * Fd)/Fm Deviation Ratio: D, D= (Fd)/(Fm Max) Carson's Rule for calculating FM Bandwidth... BW = 2(fm + AF) - OR - BW = 2(Fm + k * Fd) * Fm Which basicly means that if you can design a say... PLL carrier generator & a suitable modulation system, you could in theory modulate your carrier, with your carrier therefore transmit no relevant information, and by doing so at a suitable voltage you would have a system that would transmit noise across a broad spectrum essentially blacking out relevant bands such as GSM, GPS, WiFi etc... Due to the nature of radio though, one would have to be very careful to apply proper filtering to ensure that your not going to be causing interferance to other bands... cos that would be bad karma... Cheers! 
|
|
#2
10-11-2006, 04:41 AM
|
|||
|
|||
|
or you could just follow this http://www.hackaday.com/2005/02/22/cell-phone-jamming/ its been out for ages
|
|
#3
10-12-2006, 04:26 AM
|
||||
|
||||
|
@Bird
I built a jammer very similar to the schematic you posted. It works perfectly. My favorite manuever is when I see someone talking on there cell phone will driving, I drive up next to them and get there attention (usually honking). I take out my cell phone and make a scene of my flipping it closed (and thus ending any call that I would be on). I then click the button and watch there face as there call is dropped. Good stuff, stupid none the less.
|
|
#4
10-12-2006, 06:56 AM
|
||||
|
||||
|
Hey, Where at the plans on makeing that cell phone jammer?
__________________
Hey, My Name is Gregg Howard, I live in Ohio. Going to School for Networking and Still Learning...
|
|
#5
10-15-2006, 10:53 PM
|
||||
|
||||
|
Umm... Did you try clicking the links in the hack a day article? One of them works. Honest.
|
 |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
|||||
Linear Mode
