GSM JAMMER

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arunragavan

Joined: 01 Jul 2004
Posts: 487
Helped: 21
Location: India

15 Jan 2005 8:34 gsm jammer circuit

Well as a small project one of my frnds wanted to design a GSM jammer circuit.

What wud be the requirements for such a design. He wanted to know more abt this ckt..

is it possible to jam CDMA signals.. as per my knoledge GSM operates at low power so it wud difficult to jam those signals.. as they do not fall between the high power bands.

can someone help me reg. this GSM jammin ckt and the basic requirements..

with regards,

C-Man

Joined: 19 Jul 2001
Posts: 1235
Helped: 73

15 Jan 2005 8:41 gsm jammer schematic

I do not remember from where I got this but maybe it is a start ...

Please note that in most countries jammers are illegal!!!!

best regards

Sorry, but you need login in to view this attachment

purifier

Joined: 30 Nov 2004
Posts: 219
Helped: 1

14 Feb 2005 16:32 gsm jammer project

Did anyone test this circuit? Please help me...i'm planning to do this....

E-design

Joined: 01 Jun 2002
Posts: 947
Helped: 68

14 Feb 2005 16:47 gsm jammer schematics

It works. PM me if you want more details.

Tornado

Joined: 26 Apr 2002
Posts: 341
Helped: 1

14 Feb 2005 23:07 gsm jammer schema

Someone has made some PCB layout?

Tornado

gorkin

Joined: 27 Feb 2002
Posts: 679
Helped: 11

15 Feb 2005 1:28 build gsm jammer

What is "jammer"?

gorkin

aravind

Joined: 29 Jun 2004
Posts: 622
Helped: 23
Location: india

15 Feb 2005 2:51 how to make gsm jammer

jammer is a device which block calls in cell phones. it genarate high frequecy noise signal which should be destore / disconnect the calls in cellphone. we can hear any sound when hammer is place near u.
sound like FM signal hear in ratio.
bye

sHoEsTRiNG

Joined: 08 Dec 2004
Posts: 8

16 Feb 2005 2:11 cdma jamming

is it really possible to "jam" a digital signal from GSM phones?

TheHungry

Joined: 06 Mar 2002
Posts: 214
Helped: 2

16 Feb 2005 17:58 gsm jammer

Yes

This is possible for limited area.

jhallows

Joined: 01 Jan 1970
Posts: 88
Helped: 3

16 Feb 2005 19:17 make gsm jammer

What are the following parts on the schematic:

M2 28 x 400
L6 No part number given
947T IC? Module?

arunragavan

Joined: 01 Jul 2004
Posts: 487
Helped: 21
Location: India

16 Feb 2005 19:19 gsm jammer scheme

well dude it is possible to jam only GSM Signals and not CDMA.. coz CDMA can never be jammed thats the nature of such phones..low power..

with regards,

Debeli

Joined: 29 Aug 2003
Posts: 69
Helped: 2

16 Feb 2005 23:01 gbppr.org

" it is possible to jam only GSM Signals and not CDMA.. coz CDMA can never be jammed ... "

Unforunatelly not true. Any communication system can be jammed. To do it with CDMA you need approx 20 dB more power as for GSM for the same distance, but if you want to do it in your room... (but it is illegal, too)

byom

Joined: 19 Feb 2005
Posts: 10

22 Feb 2005 12:57 simple gsm jammer circuit

can any one give me detail ckt about the components and the related data on JAMMER. i m doing a project on this . please help me
byom

flexx

Joined: 19 Feb 2005
Posts: 86
Helped: 3

02 Mar 2005 1:02 how to make a gsm jammer

is there any easy GSM Jammer to built to cover 10*10 Meter Area ?

and i need more details about the jameer here in this topic , details about the components whitch you used to make your Jammer circuit

Regards

rommelm

Joined: 02 Sep 2004
Posts: 36
Helped: 1

02 Mar 2005 10:21 circuit gsm jammer

Where can I get the details of the circuit? can you post it here?

thanks in advance

Moss

Joined: 24 Jul 2001
Posts: 187
Helped: 7

02 Mar 2005 10:42 gsm jammer pdf

Quote:

To do it with CDMA you need approx 20 dB more power as for GSM for the same distance, but if you want to do it in your room... (but it is illegal, too)

In case that you use narowband signal for jaming, indeed you need 20dB more power. If you use jaming signal with bandwith comparable with CDMA signal you didn't need more power. That is theory...
In real world, you allways will have 20 dB( and many more) in close field over CDMA signal, because he is very weak.

actra

Joined: 09 Nov 2004
Posts: 92
Location: cairo [EGYPT]

05 Mar 2005 19:58 gsm jammer pcb

i think every system need different technique for jamming

GSM needs a sweep carrier that sweeep all the workin GSM band fast...

CDMA need a CW or narrowband noise!!

Added after 4 minutes:

check this website ...it has a detailed project with pictures abotu how to construct a GSM jammer for the 900mhz band :

http://kleiner-onkel.de.vu/

prinsloo

Joined: 19 Sep 2004
Posts: 94
Helped: 1
Location: Bethlehem RSA

05 Mar 2005 21:29 gsm jammer circuits

Try this jammer www.gbppr.org

Buriedcode

Joined: 06 May 2004
Posts: 327
Helped: 34
Location: London

06 Mar 2005 6:56 schema jammer

hi, just thought I'd butt in here,

I'll for-go the 'moral' issues raised by this, and the warnings of legality, since it would be breaking the law. Most countries come down very heavy on such actions, not just 'radio' emissions, but specifically phone interference. Safe to say, I strongly disagree, on many levels.

You're all talking about GSM, off the top of my head, second generation mobiles (most common) work on 900 and 1800Mhz. Uplink and downlink are separated by about 50Mhz, band width is 25Mhz for 900, and 50Mhz for 1800. CDMA phones are very tolerant to interferers, but they can be jammed, just like you 802.11b LAN can be jammed, although the spreading sequence in CDMA and code are significantly longer. All these systems have hopping capability, and will hop anyway from time to time to spread network traffic (no-one has the same channel for long). If you are near a base station that has both 900 and 1800Mhz capability, and you want to jamm all mobiles in a specific area, you would need two separate transmitters. OR - A big, fat, dirty transmitter that spits out harmonics like their going out of fashion Smile

Although all mobile GSM systems are really good at coping with this, you wouldn't have to damage the radio links too much for mobiles to stop working. Most phone companies would rather cut you off than give you a 'bad line'. peoples phones would still show they have coverage, but they would be unable to make or recieve a call.

My advice would be, keep it simple. You want a wideband transitter to nail either the uplink, or downlink. (I would go with downlink since the signal from the phone is strong, and the signal from the BS is weak, and you would be nearer to the phones). Also, let there be harmonics, specifically, 2nd order (double the centre frequency), that way you can get 900Mhz and 1800 at the same time. So just build a FM transmitter, feed it with noise to randomise and spread the band, and don't bother with the usual hassle of reducing emissions. Sharp edges in your PCB, no shielding, and lots of power (3-5watts?). No point in complicating it, unless you want to 'eaves-drop' in which case, it becomes an electronics nightmare.

Still disapproving,

BuriedCode

jojokatada

Joined: 13 Jan 2005
Posts: 257
Helped: 13

07 Mar 2005 18:38 simple jammer

prinsloo wrote:

Try this jammer www.gbppr.org

this link not work

seadolphine2000

Joined: 12 Apr 2005
Posts: 621
Helped: 39

21 Apr 2005 6:25 jameergsm circuits

I download the pdf and I have questions concerning some components:
1- The coils (L1, L2, L3, L4)
are they air core.? how many turns.? gauge wire.? diameter.?
2- What is M2(28X400).?
3- What are these chips(947T, MAR7, RF2104).?
4- What is "SWP IN".?

Hope I could find some details. Thanks

sunn

Joined: 21 Sep 2001
Posts: 67
Helped: 5

16 May 2005 4:48 jamming cdma

seadolphine2000 wrote:

947T is a vco covers GSM band, MAR7 is a MMIC made by Mini-circuits, RF 2104 is a medium power amplifier made by RFMD. they all can be replaced by other brand ICs.

L1, L4 can be wire-wound 1008 size chip inductors, L2 and L3 should be air coils such as coilcraft SMD spring coils.

M2 is just a microstrip for matching between MAR7 and RF2104. more detail ca be found in RF2104 datasheets.

SWP IN is just a DC sweep voltage such as sawtooh signal.

jediknight

Joined: 27 May 2005
Posts: 18

27 May 2005 7:12 gsm jammer design

Hello E-Design,

You mentioned in your earlier post that you've made the GSM jammer.
Can you provide more information please?

Regards,

JeDi

E-design

Joined: 01 Jun 2002
Posts: 947
Helped: 68

27 May 2005 7:39 gsm jammer+london

Yes, as sunn said the components are a VCO for the band you want to use together with a amplifier from RFMD. I made a sawtooth sweep circuit to adjust the upper and lower sweep limits. This was running at about 1kHz or so. In my experiments I could block phones within a 70m radius from the unit. I later made it into a dual band unit covering the 900 and 1800MHz band. This was only done as an experiment and never put to use for any other purpose.

E

eYe

Joined: 12 Aug 2001
Posts: 105
Helped: 1

27 May 2005 8:13 www.gbppr.org

My recommentation...
try to jam pilot channel instead of voice channels.

Jack// ani

Joined: 02 Dec 2004
Posts: 488
Helped: 25

27 May 2005 20:21 gsm jamming techniques

What is a pilot channel??

eYe

Joined: 12 Aug 2001
Posts: 105
Helped: 1

29 May 2005 8:06 cell_jammer.pdf

During the standby status. All mobiles will connect to Cell sites only in Pilot Channel.. then when there is a incoming call or a outcoming call, Cell sites will connect to Control center to desires with voice channel will be assigned for voice communication between which cell site and the mobile.

If we can jam pilot channel, No phone call will be initiated for communication except it is already assigned (in use).

Another type of Jammer is Cell Site Interceptor, It will take over the cell site funtion and then it can relay signal or block the signal.

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29 May 2005 8:06 Ads

redhat

Joined: 01 Aug 2004
Posts: 122
Helped: 2
Location: Egypt

29 May 2005 16:18 gsm pilot channel

Hello eYe
if you want to jam the pilot channel, how could you know the frequency band assigned to it?

Regards

gam

Joined: 25 Mar 2004
Posts: 117
Helped: 4

31 May 2005 7:10 schematic gsm jammer

Hello,

Illegal as it may be to use jammers, from the technical discussion pov, I think that the jamming process depends on the following factors:

- distance or cell area to be jammed
- Power that the Base Station is transmitting at or its EIRP (depends on transmitter power and the antenna gain), and the height of its antenna
- Sensitivity of the receiver
- Losses for the wireless link

from the above you cn make a very simplified "link budget" and calculate the amount of power you need for your jammer.

For GSM I agree that you should jam the pilot channel of the cell (called the BCCH in GSM) as if jammed it will block all service in the cell, however this is the channel that is transmitted with the most power and it is always on (beacon channel). Other channels (traffic channels TCH) are transmitted on per need basis and have the ability to hop on several frequencies (one freq each time slot) so if you try to jam a TCH you may cause bad quality but not block the service.

To know which channel is the BCCH, you can use a trace mobile software, on old nokia phone there waqs a "netmonitor" software that showed you the signal level on your cell and neighbor cells.

For CDMA and its derivative (WCDMA, etc) the channels are wideband relatively (1.25 MHz (IS95) and 5 MHz(WCDMA) versus 200 Khz for GSM channels) and it is very tricky as the CDMA system is designed to extract the required signal from all the interference (users use the same frequency in the cell), however it can only extract the info as long as the total interference is below a certain level, by adding a certain amount of interference from your jammer you can easily block this channel, the problem being to have to generate a big bandwidth signal (up to 5 Mhz)

Regards