Synopsis
on
Cell Phone Jammer
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INTRODUCTION &WORKING:-
A “Cell Jammer” is just way of saying “Dirty Transmitter” which happens to
transmit within the Cellular Phone Bands. Reality is, the dirtier the better.
The 555 timer [8 pin] IC simply makes a noise. It’s coupled via C4
[electrolytic] to modulate the MRF transistor oscillator. With C1 set at
roughly 1/3rd, you will be close to 900 MHz. By sweeping the C1 trimmer
capacitor, you can swing the output frequency from 800 MHz to 2 GHz with
the
transistor
and
values
shown.
You could replace the 555 chip with an electret microphone and listen to
yourself talk on a scanner, so the unit could easily couple as a UHF Bug.
Instead of a single Tapped Coil, I’ve used two molded inductors for ease of
construction.Values for C1,C2,L1,L2 are critical for the frequency range.
You might want to build the unit into a metal box, add an on/off switch in
the batteries + line, and maybe even add a LED. Connect an old 800 MHz
cell
phone
antenna
to
C5.
Would you believe the whole thing can be built on top of the 555 IC itself
when using surface mount components, and the lot will fit onto a nine volt
battery clip. Output is reasonably good, although the current drain is a bit
high, so a new 9 Volt battery will only run about an hour, [if you are lucky].
The “Cell Kill Distance” is around 10 – 15 feet, ample for most purposes.
Radio jamming is the (usually deliberate) transmission of radio signals that disrupt
communications by decreasing the signal to noise ratio. Unintentional jamming occurs when
an operator transmits on a busy frequency without first checking whether it is in use, or
without being able to hear stations using the frequency.
Another form of unintentional jamming occurs when equipment accidentally radiates a signal,
such as a cable TV plant that accidentally emits on an aircraft emergency frequency. The
concept can be used in wireless data networks to disrupt information flow.[1] It is a common
form of censorship in totalitarian countries, in order to prevent foreign radio stations in border
areas from reaching the country.
Radar jamming and deception is the intentional emission of radio frequency signals to
interfere with the operation of a radar by saturating its receiver with noise or false
information. There are two types of radar jamming: Mechanical and Electronic jamming.
As with other radio jamming, cell phone jammers block cell phone use by sending out radio
waves along the same frequencies that cellular phones use. This causes enough
interference with the communication between cell phones and towers to render the phones
unusable. On most retail phones, the network would simply appear out of range. Most cell
phones use different bands to send and receive communications from towers (called
frequency division duplexing, FDD). Jammers can work by either disrupting phone to tower
frequencies or tower to phone frequencies. Smaller handheld models block all bands from
800MHz to 1900MHz within a 30-foot range (9 meters).
Co
mpo
nent
s
Req
uire
d:
NE5
55
Timer
Resistors
82kohm
6.8 k ohm
220 ohm
10k ohm
capacitors
5 microfarad
50 pf
1pf
20 pf vaiable
Inductor
2.2 nH
1 nH
Antenna Longe range -omni- 10 meter range
Block Diagram:
Antenna
Oscillator
Frequency tunning
Bibliography
www.mobilejammer.com
Noise Generator
Amplfier
www.radiofrequencyjam.com
www.ips123.in
www.circuitstoday.com