Radio Jammer




This Item is a Radio Jammer. It sends out EM waves of a certain frequency.

Before you enter:
This item is illegal in certain locations. It is only demonstrating how these items work and what only a few dollars at a electronic store can build.

This also Not a Cell phone jammer. Jamming a Cell phone is similar on its principle, but totally a different build, you need a range from 800MHz to 900MHz. You need an OP amp and a few other parts and formulas

F = 1/(4*R1*C)*(R2/R3)
R3/R2 (noticed it flipped) is the frequency range

850MHz = 1/(4*R1*C)*(1/50MHzS)

You must know the fact that they are illegal in certain areas and MUST NOT rant about it and say they are illegal.

Step 1: Precausion

This Item May Be Illegal In You Area, Check It Out Before You Build.
I am not Liable for any offenses.

Why This Works:
The Radio Jammer sends out a EM wave at a frequency. The wave is then broadcast throughout an area. Radios will receive this wave (when tuned to that frequency) and It will block the other wave that is broadcast from a station.

So far in my building, I have only been able to block 1 station using one OSCILLATOR.

Have tried adding 1.5v onto a 9v battery. This unexplainably let me listen to another channel on the channel I was blocking.

Step 2: What You Need

What You Need:

An Oscillator, The heart of the Radio Jammer. The frequency you choose will be the frequency you jam. FM radio is in MegaHertz. Example, If you want to block 100.0, then use a 100Mh Oscillator. It may be a bit confusing. I have a 97.7 MHz that says 97M70000 and a 50 MHz that says 50.0000 MHz.

A 9 volt battery

A L.E.D.

An Antenna


An On/Off Switch

A Circuit Board (Optional, but recommended)

Soldering (Used with the Circuit Board)

Price list:
Oscillator: $2.50
9 Volt Battery: found it somewhere, but i think there maybe $1.00
L.E.D.: $0.10
Antenna: $1.00
Wiring: found in workshop, i got a lot for $1.00
On/Off Switch: $1.50
Circuit Board: $0.50
Soldering: $1.00

Total: $8.60

Step 3: Assembling!

If the Writing is confusing, Look at the picture

First, get your Oscillator

On it you will see 4 leads

The locations of the leads in () will tell you the location looking at it RIGHT SIDE UP, meaning that the righting will be right-side up, and the lead with the black dot will be the bottom left, and the square corner instead of the rounded corner will also be bottom left.

1 lead (bottom left), the one with a black dot on it, and it also has a square edge instead of a rounded one is Only to hold it on the circuit board and does not need anything attached to it (It shouldn't be attached to anything anyways).

the lead diagonally across from it (Top Right) is to be connected to the antenna.

The two remaining leads are for the voltage source.
The Top Left lead is connected to the +ive end of the battery. The Bottom Right lead is connected to the -ive end of the battery.

Look At the picture

Step 4: Now That Your Done!

Now that your done the wiring.
You can solider it to a circuit board (optional)

Turning On the jammer will send out an EM wave of X (X is the frequency of the Oscillator)

Tun on the oscillator and... Nothing
You have successfully jammed a radio signal!

Step 5: Extra

This is my finished version
It looks really nice

Cutting the plastic was really hard and could have been done a lot easier and safer with A Laser Cutter :). I got a cut when I was carving out the hole for the on/off switch.
Also, cutting thick parts of out of the phone frame would have been a lot easier with A Laser Cutter.

I burnt myself with the soldering iron :( (unfortunately A Laser Cutter wouldn't have stopped it, but...

I also tried opening an Oscillator with some pliers but unfortunately, i broke everything inside and the metal was sharp, maybe I could have done it easier with A Laser Cutter.

Anyways, Thanks for reading my Instructable, and do not rant about how this is Illegal.



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    170 Discussions


    3 years ago I am relatively new to this (I mean computers, software, and the physical properties of sound,) and this question is a little off topic: Let's say, hypothetically, that I am personally hearing human whispers directed at me and these whispers sound exactly like someone I know, hypothetically of course. If I wanted to mask or completely cancel his whispers, which I realize are two entirely different processes, could one of you give me some ideas on how to do so, respectively, and if not maybe provide me with some helpful resources or links? I will attempt to outline my current plan of attack, or should I say defense...Preferably I would rather cancel than mask (keep in mind that some of my thinking /theory may be wrong). First: I would need to record a whisper that fell within the same frequency range (wondering if tone and intonation play a crucial role? Is a whisper considered a flat, non harmonic tone?) of about 5 to 50 Hz. Second: either design a radio jammer or use a DAW, thanks Ecapsretuo, to broadcast this signal over the specified frequency range, but inversely (??? to cancel a sine wave I would need to overlap 3-4 of same recording 180 degrees out of phase to each other in a loop, but how do I determine how long the period should be???). If I used a spectrum tuner could I hone in on exact frequency and adjust accordingly? I would like this system to be portable so I am wondering whether a jammer (i.e. oscillators and/or circuits) or a compressed digital recording in mp3 format would be more practical? After all, both of these could be amplified at a later point to mask the original signal/sound/whisper...correct? Raising another question: Modulation. What type of program would be suitable and over how much area do I need to broadcast the carrier signal? In the case of the jammer, would I accomplish this with an external amplifier or by boosting battery power? If I can't determine exactly what this guy's going to say, how can I mimic the EM wave? Maybe masking is the better solution ??? Someone please help!!!!!!!

    10 replies

    Reply 2 years ago

    Mate you need to block a frequancy between 14.5kHz and 14.8kHz im after the same thing. This will block "silent sound" ;-)


    Reply 2 years ago

    If you are hearing voices while near your computer and its may have a Trojan, like the old sub7, which allowed speech through the onboard speaker, remotely, among other things.


    Reply 3 years ago

    If you're hearing voices directed at you without any known source then you should see a doctor. Conditions will get worse the longer they go untreated.


    Reply 3 years ago

    Thanks doc...what I was looking for was a scientific explanation not a cracker-jack diagnosis. Thanks for your invaluable insight.


    Reply 2 years ago

    Hi jotclot, I was wondering if the whispers were still bothering you, or if you perhaps had seen a doctor for their opinion yet?

    Don't let the other posters calling you crazy get to you, you're not. Unfortunately though, if you don't see a doctor about it, the whispers could eventually drive you crazy.

    I hope all is well with you.


    Reply 3 years ago

    I'll have you know that cracker jacks are nutritious and essential for life.


    Reply 3 years ago

    You need to look into voice to skull-V2K / synthetic telepathy / Electronic Harassment and ORGANIZED STALKING #Gas lighting / Gang stalking /Cointelpro

    Micro wave Hearing what you hear is a CRIME BEING PERPETRATED ON YOU! Seriously


    Reply 3 years ago

    Thank you for the straight up answer : you're the first person to actually listen to me...believe me when I tell you, I'm not crazy and it is very much a crime...once again , thanks. I may message you back if I have any questions for you . Hope that's ok.


    Reply 3 years ago

    The physics behind the transmission of sound waves and the transmission of EM waves are quite different. With that said, the theory behind your idea of pi shifting a sound wave into destructive interference is solid. Noise cancelling headphones use this principle. I suspect any device you could build would share more in common with noise cancelling headphones than the jammer above. One of the greatest difficulties will be that the human voice is an incredibly intricate wave. You would need sophisticated recording equipment to achieve a strong effect.

    I have to agree with rlogan, if you are hearing whispers from an unkown source, that is a sure sign of a health condition. You should seek medical advice.


    Question 5 months ago on Step 5

    which type of antenna were used to transmit the EM waves


    6 months ago

    A friend of my said cellphones jam at 900 to 1800 MHZ and my 555 timer goes to 100 KHz max it too low a freq to jam cellphone perhaps a radio signal. I am using texas insterment types a good quality.


    6 months ago

    Has anyone used a Magnetic loop to produce a cellphone jammer with a high frequency 555 timer circuit. I plan to build one.


    1 year ago

    Just to let you in Canada broadcasting and maybe sending out signals to block radios could get you 2 years in Jail and a 5000 doallar fine. Also an criminal record so do these things if they are legal INDOORS ONLY.

    Thanks for reading and following (I hope) to this advice.


    3 years ago

    To jam all stations, just use a small, high-voltage transformer connected directly to a copper coil. Works like a charm.


    5 years ago on Introduction

    Will this device work on CB base stations ? If so, what is the range in miles of radios that will be affected ?

    1 reply

    Reply 3 years ago

    No I think UHF jammer needed?