FM Radio jammer
Description.
Circuit shown here can be used to jam FM radios in its vicinity. The circuit is nothing but a classic single transistor oscillator operating in the VHF region. Working principle of the circuit is very simple and straight forward. Powerful VHF oscillations from the circuit will interfere with the FM signals to nullify it. Jammer circuits like this are illegal in many countries and you must assemble this circuit on your own responsibility. This circuit is intended only for fun and i request you not to misuse it.
Circuit diagram.
Notes.
- For L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former.
- The circuit can be powered using a 9V PP3 battery.
- For extended range, use an antenna.
- A 30cm long wire connected anywhere on the coil will do for the antenna.
- For better performance, assemble the circuit on a good PCB.
You may also like:
Custom Search
please need help! i couldnt find 16 awg wire.i m having 4 awg.can some tell to make inductor of 4 awg wire??????????As i hav selected it as my semster project i will have to make presentation in few days!!!!!
I couldnt find 6pf capacitor.can i use 1pf and 5pf in parallel??plus i m having 4 awg wire will it work???16 awg is difficult to be found.
Hi I would really like try out this project. Can you send me the components details and working to my email_id sreeramdgr8@gmail.com
any body can add me for discussion my email is usmantoday@hotmail.com
hey, can i have the list of components with all the power rating and stuff…i want to make this for my college project….so i would like to have the list of all the componnts with all the specifications ASAP
Hi,
can i use 2n2222 plastic case or shd i use metal 2n2222 transister only? please confirm.
also anyone tried this circuit and is it works fine??
This device can also jam tv. .
hi i tried this circuit but..i don t know what really went wrong cos i followed it properly still it did not work out
many oscilators but no 50Hz oscilators..?
Hi friend the inductor is the part of the tuned circuit ( L1 and C1) resonates at the required frequency. The in ductor need not be very accurate.
Does anyone know how many henries that inductor is? I tired using this: http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=util_inductance_circle with the result being 270 nH. Does it really matter how accurate it is? I’m thinking it’s supposed to act as a small range antenna.
Hi Raj assemble the above. tune FM radio to a station now switch on the above circuit adjust C1 till the FM station is blanked with the carrier beat.
how can i start up the experiment
Hi Arun for increasing the power you read my comment dated 6th june. you cannot jam the entire FM band with a width of 20MHz by this simple device.
how can i block the full fm freequency at atime(88Mhz-108Mhz
how can i increase the range of fm jammer
Hi Bryce they are listed in 4 pages of RS catalog on passivie c omponents. you can visit the following site and deside http://in.rsdelivers.com/catalogue/category/trimmer/3377.aspx?pg=1
what is the items part number and how do i find it
Hi Bryce you can try with one of the suppliers
http://www.cheaponsale.com/d-c116022938019608100-indian_components_sales/
RS Components & Controls India Limited
is indian market the name of the wedsite if not what is the name of the wedsite
Hi Bryce in the indian market
Hi Jem it will be suitable for frequencies from 60 to 200MHz.
heya, thanks alot for the link man, helped out alot, i apreciate the help you’ve given. would it be alright to use the ceramic variable caps they sell also, i’m planning on making a pcb and size matters lol, plus the capacitance more closely matches your design
also, could this schematic be used with some few tweaks to jam all sorts of frequencies, like cell or AM or anything else?
where did you get the varaible capacitor
Hi C1 is a pre set capacitor ( trimmer capacitor) if you cannot get it you can use two length (2 to 3 cms) single strand strand plastic hook up wire and twist them together to achieve 2 to 10PF or so. now expand or compress the coil to achieve the required frequency. http://www.surplussales.com/Variables/VariableTrimmers/VarTrimm5.html
Alright, thanks for the help, i apreciate it alot, now, i’m just wondering where to get the variable cap, i’ve found out all the different names and corps that manufacture them, but so far all the places i’ve been to haven’t seen or heard of them in about five years
online is the same, i’ve so far found one site but its over in england, 
and sites or tips you have would be great to circumnavigate this issue, (eg. something else i could use, a site, etc.)
Hi Jem it is common ground, that is earth plane of your antenna. If you donot want earth plane you can leave it and use only the wavelength / 4 whip antenna.
I have not tried simulation but tried the circuit and it is working alright.
I’m using this program i found that electronically tests circuits, but its not working
this is the site
http://www.falstad.com/circuit/
you have to have java enabled
ok thank you, now just one more question, i know what all the components are in this, but i’m having trouble translating in my brain how they all connect, i know it should be all easy because of the blueprint, but like, does the second path coming down south off the 9volt source, is that just another positive, or is that the ground coming back to the batter? and if so why the ground symbol on the bottom, is is a common ground for all the components?
Hi Jem You can use components of 16volt and above. Minimum should be 16 volt. it can be 100volt still safe
hey, i’m trying to build one of these, and i was wondering, do the components have to be rated for 9 volts? cuz i’m looking for one of those variable trimmer caps and all i’m finding are ones that have a working voltage of 100
Hi Dishant it is in uH, not readily available and easy to wind air core 8 t0 10 mm id, 6 turns wound with 16 to 18 gauge wire with a gap between each winding of wire thickness.
hi can u please give me value of L1 in henry?so that i can directly use inductor having that value?
Hi.
And if i want to block the whole fm band 88-108mhz.How will i to do?
hai friends if want ask any doubt contact the emailid arivueee@gmail.com
very use fuul
Hi Bryce yes. but if you want to only jam a particular broadcast tune only to that.
would you have to adjust the Fm radio jammmer’s varaible capacitor every time you changed the station on the radio
how many uh does the L1 have
Hi Gino L2 is the Tank coil to match antenna. you can use the one similar to L1 and tune it for the maximum radiated power
i think the configuration of two transistor is momething like that:http://english.cxem.net/radiomic/bug29.php
T2+T3 do the job for increasing power. I don’t know L2 what is used for!
what if I connected a fm transmitter to the fm radio jammer would the wireless range change
How can i increase power? Adding another transistor as Rf amplifier?
Hi Bryce within the house only.(less than 100 feet)
what is the wireless range for this circuit
No former self supporting coil, 16 to 18AWG any one can be used.
does the L1 have to be a 16 awg wire plastic former just give me a staight up answer.
Hi Bryce it has to be in the range of 3 to 35PF. you can use FM tuner variable capacitor also.
could I use any varaible capacitor or does it have to be a varaible capacitor that is 6-35 pt
Hi Bryce super enamelled copper wire of 1mm dia is well suited. (16 to 18 AWG)
If you want to jam that station tune in and jam with jammer.
does the L1 have to be 16 awg
DOES THE RADIO HAE TO BE ON A CERTAIN STATION
Hi Bryce what capacitor value you have used for C2. It can be upto 10PF ceramic disc, L1 should be 6 to 9mm dia air core with 18SWG super enameled copper wire close wound 5 to 6 turns. set the trimmer C1 at the center.
once the circuit is assembled keep it close to an FM radio tuned to around 100MHz. now switch on the jammer, with a plastic tool expand the coil axially till a blank carrier is heard in the radio. now your FM radio jammer is ready.
why is nt his circuit working when I tested it help me
Hi without emitter resistance the transistor will blow of. Resistance can be a near preferred value. THE JAMMER CAN WORK WITHIN A SMALL COMPOUND ONLY.
would 3.9 k=3k and 900 ohms
does the circuit parts have to be exsactly right (I cant be a ohm or a uF off)
what is the wireless range of the fm radio jammer
would the fm radio jammer work without the resistors
Hi Bryce by reducing emitter resistance and providing heat sink to 2N2222 and increasing the supply to 12volt you can achieve your requirement. you can replace 2N2222 with 2N2219 for better power desipation
what if you doubles all the capacitors Uf’s and transistors current will the wireless range change
Can Anyone tell me the value of INDUCTOR in henry?or any other compatible inductor..
[...] Notes. For L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former.The circuit can be powered using a 9V PP3 battery.For extended range, use an antenna.A 30cm long wire connected anywhere on the coil will do for the antenna.For better performance, assemble the circuit on a good PCB. Link – circuitstoday [...]
The legality of the circuit depends on how and where you use it. It is basically a CW generator so a radio will just pick up silence. It differs little from the little transmitters that allow a CD player to be picked up on a nearby radio. There’s just no input where a mic or CD player could be attached. In most jurisdictions, the limiting factor is SWR. So if it can only be picked up for a few meters, the legality would depend on how you use it. If you’re only interfering with your own radio, it should be alright in most places. If you’re intentionally interfering with other peoples’ radios, then it’s illegal almost everywhere.