Instructables
Picture of How To Create Your Signal Jammer
For a long-long time many people were looking for this cool recipe of making something interesting for yourself. And I was one of them until last days. In my quest I came across the Jammer Store blog post called How To Make Your Cell Phone Jammer: DIY Guide. It inspired me to make something like that by myself.

All necessary info, schemes and pictures are there, so I tried. The result is represented in this humble guide for you.
 
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Step 1: The Basics

Picture of The Basics

This signal jammer uses 800MHz frequency to operate because many cell phones are working on the same frequency. So I chose the sweeping oscillator as my VCO. It is really efficient yet may be difficult to use if you are beginner without some semi-professional RF-testing tools.

The clock oscillator (45MHz) is driving a local oscillator port as my noise source and is located on the mixer of the mini circuit. To equate the impedance of a clock oscillator with the mixer there is an impedance matching network. Local oscillator signal goes through this network and impedance is matched.

The 800MHz antenna from the old cell phone is connected to the RF input (mixer port). The RF output then goes to the amplifier located on the mini circuit. The amplifier will increase produced output by 15-16dbm of pure power. The empowered signal is going to another old phone antenna.

Step 2: Your Jammer Works!

Picture of Your Jammer Works!
GSM800 cell phones have their frequencies separated by 45MHz exactly. So when any cell phone tries to make a call - it becomes blocked by itself! The phone talker will hear its own voice.

You can also keep in mind that this cell phone signal jammer can block all cell-based trackers which use your car GPS to track you down and record the data. Even IEDs are probably could be jammed, at least those ones controlled by cell signals.
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shiaulteyr2 years ago
Swapping out the sweeping oscillator with one from the phone itself, an old router - if you're interested in those bands - and other electronics (such as old RC toys, which makes those crack-of-dawn RC plane enthusiasts quite down nicely) should work with this design too. That is, in theory at least. Great project to experiment with though!! Good work!

Just on the IED topic there - we used to use a similar device in Afghanistan when the opportunity presented itself and I know that many Police agencies have them in their arsenal - where they provide, I'm sure, much more use than they did for us! (By the time you find out it's a cellular triggered device, you're probably already picking up what's left of it after it went off the day before! Not to mention, setting the phone's alarm as a backup/failsafe is immune to jamming - as are grenades).
and i hate to say / type this. depending on the phone. the alarms wil still go off even if its in stand by mode. then depending on the phones battery, it can be in stand by for up to a week. if u want it to last longer put in a small solar panel.
BearGrills (author)  shiaulteyr2 years ago
Thank you for nice words and advices! It is pleasant to know that similar devices are saving lives out there :)
AkashA13 hours ago

price of the oscillator in india and total circuit in india let me know via sms.

ph no; - 8906963960

don't call please just sms me.

Hi, I have taken RF circuit design course in my grad school ( Basically I am in VLSI field, so I am novice RF circuit designer!) I understood your schematic well, i.e requirement of matching n/w the transmission lines, and how this works and all, so i thought I shoould make it. So I started with finalizing 45Mhz crystal, To my surprise, I was not able to locate the Output Impedance of OUT pin of the OScillator anywhere in any of the datasheet i referred/read. So can you tell me :
1) Am I missing anything, the last thing I saw as Ohm was ESR ( Extended Series Resistance ) in few Datasheets, Should I assume that its the OUT impedance?
2) Is there any formulations and all ?
3) If you can, pls mail me at kk.1821(at)gmail(dot)com

chiruc17 days ago

it is very easy to prepare...............?@chiruchary123@gmail.com

chiruc17 days ago

it is very easy to prepare...............?@chiruchary123@gmail.com

how can i increase the signal to this device?im working on a college project,but i have no idea with these electronic stuff. i need much help,thank u. email me here perfake92@yahoo.com

am tech2 months ago

but I think I'm going to make it anyway!

am tech2 months ago

isn't this illegal I was reading a jammer article that says if they caught you th

ed lock you up and throw away the key.

shubhamelec3 months ago

can i use a crystal oscillator insted of the one u used in the project

shubhamelec3 months ago

can i use a crystal oscillator insted of the one u used in the project

shubhamelec3 months ago

can i use a crystal oscillator insted of the one u used in the project

santpyara3 months ago

pls show the circuit

hohum5 months ago

I noticed there is knot of red and black, is that where you put the ferrite cores?

Shajeel8 months ago

mere baaaaaap circuite tou dikha de kam se kam

zarmons8 months ago

hi you there.can you send me a schematic diagram and the component part? my email zarmons_613@yahoo.com.i like you project and i want to make like this kind of project.

thanks adnvance

zarmons....

nicostar231 year ago
I want to make one that will crash everything in my school. What should the output(s) be?
if u go that route. u can be branded as a terrorist. because u never kno who might have a pace maker 4 thier heart.
badsting1 year ago
Where should I get old phone and which best MHz ?
try dx. com an or alibaba.com then try many pawn stores . uill sure to find 1 yr looking 4.
hiyer2 years ago
hey i want to make signal jammer as my project . so can you pls send me the list of compenents and the procedure to my email id i.e hvignesh91@yahoo.com
kcrow11 hiyer1 year ago
the list of components ins written clearly in the circuit diagram....open it and you will see! the procedure on building one of these is what the entire instructable is written about, read the article before asking questions.
bro if sm1 hs send u the list of ths component plz send me also
my email id iz saber.shafi@yahoo.in
bilaljarral2 years ago
helo bro
can you help me make a jammer if you want plz sent me all component and detail on my email bilaljarral302@gmail.com,
i hope u help me
if you cant figure it out from the circuit posted above, you have no business tinkering with such things...one could really hurt themselves from electrocution! all the components are listed in the circuit schematic and all the help you need is written in the instructable.
bro if sm1 hs send u the list of ths component plz send me also
my email id iz saber.shafi@yahoo.in
BearGrills (author)  bilaljarral2 years ago
There is no need to write few times, don't clog the comments please
rg
erotologue1 year ago
Hello BearGrills,
I planning to built this jammer but I would like to increase is range ( I'm not talking about the antenna ), how could I do ? does it need another amp ?
is there any modifications to be done to circuit diagram ? . My email id is slugha_432@hotmail.com
paddys0111 year ago
Wonderful project - can anyone tell me if this would allow FM radio signals to be received whilst blocking phone signal?
Hello Bear Grilles,
I am very interested in this project and In the picture of your model I found a transistor but I dont find any in the circuit diagram , is there any modifications to be done to circuit diagram . My email id is adithya.yuri@gmail.com
http://www.arrl.org/news/fcc-issues-two-forfeiture-notices-for-cell-phone-jamming
Hello Bear Grilles,
I made an account just to ask, can you end me super detailed instructions as well as what each component's function is, I have no idea what I am doing whatsoever, but would love a quick lesson on it. My email is EArmendariz000@gmail.com
soundman641 year ago
Hi BearGrills,
Interesting jammer idea that - getting the received frequency to generate a jamming signal 45MHz offset from it. In your experience, can you tell us how effective it has been in practice? The receive and transmit antennas are quite close. So, I was wondering if the strong transmitting antenna signal would overload the receiving signal and mess the whole thing up (even though they are 45MHz apart)?
Would you not need to filter the receive signal to keep the transmit signal away from it?
Also, it probably wont block one-way text messages being sent from those accursed GPS tracking thingies, will it?

Thanks.
dinodhayal2 years ago
hi sir/madam,
can you help me make a jammer if you want plz sent me all component and detail on my email skddinesh295@gmail.com,
i hope u help me
dinodhayal2 years ago
an you help me make a jammer if you want plz sent me all component and detail on my email skddinesh295@gmail.com,
i hope u help me
mammasboy2 years ago
this is an awesome idea, could you provide a parts list and a "how to" for the circuitry side of things? i'd love to make one of these
JFaust782 years ago
I am not a professional electronics guy, but could someone suggest a part number or link for the clock oscillator. I am finding many of them, but do not know which would work for sure. Thank you so much for the great post!
sumalyo2 years ago
very very very very gooooooooooooooooood
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