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Simple Cell Phone Jammer

Posted Feb 16, 2012 at 4:59 pm
Figure:1

Figure 1 

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.

Designer & Author: Special thanks to Laszlo Kirschner.

Tags: jammer, cell phone, cell phone jammer, dirty transmitter

Comments on this post:

By kummi 1Score: 

4 years ago:  i think its cool and i want to use it as ma project. thanks

By safyan 1Score: 

4 years ago:  hi can u plz give me the detailed discription of this project i m interested basically in the electronic parts u have used i want their part number.u contact me on my email id i would be really thankful to u i m wating for ur reply

By anonymus 1Score: 

4 years ago:  hey this is a great circuit. I am using it as an extra project in my electronics class, but i was just wondering if anybody could tell me or direct me to a website that i can learn how to make a 1 and 2.2 nano henry (nh) coils. ty in advance

By jude 1Score: 

4 years ago:  there is a simple equation for the winding,

Wheeler's Formula (single layer air core coils)
L(uH) = (r^2) * (N^2) / (9*r 10*h)
where:
r = coil radius (inches)
N = number of turns
h = coil height (or length) in inches

found from this site
http://forum.allaboutcircuits.com/showthread.php?t=12870

hope this will help you!
Did this worked ?

By ethan 0Score: 

4 years ago:  yah it helped me make the coils the right size, but i still cant get it to knock a signal out. can anyone shed some light as to why this is and any way i could make it more powerful?

By gerlie 0Score: 

4 years ago:  where can i buy the MRF947T1?please email me...thanx!!

By Pran 0Score: 

4 years ago:  It would been wonderfull if the turns, diameter and the guage of the coils are given for easy construction of an average hobbyist.

By kummi 0Score: 

4 years ago:  where can i get to buy MRF947T1

By Meins321 0Score: 

4 years ago:  MRF947T1 = Motorola NPN Low Noise, High Frequency Transistor
Replaced by
PRF947 = Philips Transistor
or
MAS947 = HOPE Microelektronic

I can't find a source, can you help us please?
Farnell?

By amar gupta 0Score: 

4 years ago:  great project .....
i humbly request you to send the complete information regarding it..........
thanx in advance
my email id : .(JavaScript must be enabled to view this email address)

By Sanjay 0Score: 

4 years ago:  hi.... i also likes r&d in this field.... so please contact me on my id ok... i wants some suggesions... good bye

By Remi 0Score: 

4 years ago:  I read about the topic and it is really interesting
I would like to know that whether the same technique can be used to jam the cable tv Signals
Please reply
Thanks in advance

By sandeep 0Score: 

4 years ago:  hi sir
i would like to know wehther the above circuit could be used as a effective jammer for freq. used by gsm companies in india & other asian countries.
i would be highly obliged sir if send me the working and detailed scematics of the jammer circuit shown above
thanks

By DEV 0Score: 

4 years ago:  hi
i am from india this mrf947 tr not avible in marcket plz send equi value of mrf 947

By Priyanka 0Score: 

4 years ago:  I am not getting MRF947T1 in Kolhapur.Tell me where I can get this transister?
OR tell me replacement to MRF947T1 transister,urgently....

By Faisal Mahmood 0Score: 

4 years ago:  Im an electronics engineering undergrad student kindly send me the complete details of this project at .(JavaScript must be enabled to view this email address)

Thanks a lot.

By udy 0Score: 

4 years ago:  i am a EEE student,please send me full details about this project,... my e-mail id~b.udayakumar2008@gmail.com

By ankita 0Score: 

4 years ago:  i want to use it as my project ,please give me detail.how it work ?,component and price

By Charles 0Score: 

4 years ago:  Hey i would like to use this as a project for my EE class and would like to know more details; the components i would need and about how much it cost
.(JavaScript must be enabled to view this email address)
thanks

By di 0Score: 

4 years ago:  it will be a great help to email me the whole docs about this jammer. fortunately, our project is about jamming and i find this circuit very simple. this is really urgent. pls send me all yhe important details specially the components. thanks alot

By Jack Man 0Score: 

4 years ago:  I was just wondering if you could e-mail me a list of all the parts you used for this and were i could get them(Radio Shack?) to .(JavaScript must be enabled to view this email address) Please and Thanks

By ragubond 0Score: 

4 years ago:  hi..bro...can u pls giv me the details about the project........think me as ur bro...and do dis help contact me :ragubond@gmail.com
r through my no. 9884477652

By im not telling you, lol 0Score: 

4 years ago:  A zenner diode noise source and a power amplifier system would create emissions all across the band upto 2gz easy. you may even like to try adding some mixers and mix two noise sources together, so you get the sum and difference of both noise generators. Makes me laugh when people keep asking for the info, the circuit is right on the page, what elese could they possibly need. Shows a great level of not understanding the fundimentals of electronics engineering, read the books you forign muppets. Is it just me or is there generaly a high level of incompetance assosiated with forginers. Honestly read some books to understand how the ciruit works, otherwise you will always need somebody to hold your hand and do the work for you.

By Anthony Ike 0Score: 

4 years ago:  hi i,m a physics undergrad student desperately in need of a few detailed projects,so pls u cud snd me some including this by e mail - .(JavaScript must be enabled to view this email address)

By newbie 0Score: 

4 years ago:  Hi, I'm a EEE student. Can you send me the details of this circuit coz I think this is quite good to be a project to do. So, can you send this by e-mail .(JavaScript must be enabled to view this email address)

By Ricardo 0Score: 

4 years ago:  Hi, I'm a EEE student. Can you send me the details of this circuit coz I think this is quite good to be a project to do. So, can you send this by e-mail .(JavaScript must be enabled to view this email address)

By DANIEL MOSCOSO 0Score: 

4 years ago:  friend that such you can help me????????????

can you give me but characteristics of the source or battery????????

thank you

By anson 0Score: 

4 years ago:  1. i would like to use this as a project ,plz give me detail.how it work ?
2.mrf947 TRANSITOR not avible in marcket plz send equivalent

By rajvir 0Score: 

4 years ago:  please send me information related with LC tuned circuit. how much diameter of copper wire and no of turns we have to consider for 1nH and for 2.2nH COIL.

By rajvir 0Score: 

4 years ago:  if any alternative for this please tell me....if this trimmer frequency set avialable tell me parts number....please ....

By tarun 0Score: 

4 years ago:  1. pless tell the data sheet of mrf947 or any replacements.
2. dia of inductor coil and no. of turns

By tarun 0Score: 

4 years ago:  1. pless tell the data sheet of mrf947 or any replacements.
2. dia of inductor coil and no. of turns
plz mail me soon

By sonu 0Score: 

4 years ago:  hey this 4 indians az im too dont worry if u are unable 2 get this transistor use bfw10/bfw11 fromB.E.L. bharat electronics limited.
any querry mailme at .(JavaScript must be enabled to view this email address)
(cost of this transistor is just Rs11or12 only now stop crying to b indian

By jammer 0Score: 

4 years ago:  this looks like the orginal P2JBZ circuit from phonejammer.com do a search

By sriharsha 0Score: 

4 years ago:  hai this is harsha from kahmmam district i am an ece syudent i lik the project mobile jammer i want to this projct as my mini project which i need to submit to the university as i m belomgimmg to andhrapradesh plz sujjest me the place where can i get that her over plz think of abt my request frns


urs harsha

By ali shujaat 0Score: 

4 years ago:  hy how r u can u plzz send me the compelete info about this projects on my id that is .(JavaScript must be enabled to view this email address)
i need to make my final project plzzz help me

By Siddharth my id? 0Score: 

4 years ago:  Hi there,
i live in india, and am pursuing a project on jamming rf signals.
could u plz be kind enough to send me the circuit details (parts list, and diagrams) to

By Siddharth 0Score: 

4 years ago:  my id?
.(JavaScript must be enabled to view this email address)

By karthikeyan 0Score: 

4 years ago:  i want to know the projegt deatials

By karthikeyan 0Score: 

4 years ago:  please sent the details to .(JavaScript must be enabled to view this email address)

By Marvin 0Score: 

4 years ago:  Does any body made it?? did work??

By manny villar 0Score: 

4 years ago:  jamming phone signal is cool and very beneficial for our machines so they will not interfere with the frequency which they operate...nice one dude!

By Yogesh 0Score: 

4 years ago:  I want to know all the details about this project for theory Knowledge. Please refer me the information regarding the same.My e-mail ID is:-
.(JavaScript must be enabled to view this email address)
Thanking you!

By Marvin 0Score: 

4 years ago:  Hi i, looking your circuit and i noticed that you're using an 555 integer with one source of 9v. Remenber that the 555 uses 5V.

By Bene 0Score: 

4 years ago:  Marvin, the 555 goes to around 18V!! dont tell some shit here

By laila taher 0Score: 

4 years ago:  what is the kind and name of modulation for this circuit ,kind and specification of the used antenna ,what is the oscillator circuit elements exactly in this circuit.

By laila taher 0Score: 

4 years ago:  what is the kind and name of modulation for this circuit ,kind and specification of the used antenna ,what is the oscillator circuit elements exactly in this circuit.pleas i want to have the answear quickly at this email :lailataher2009@yahoo.com

By nivi 0Score: 

4 years ago:  i want some more details about the circuit and its operation. could you please tell me where we can get the out put

By nivi 0Score: 

4 years ago:  i want some more details about the circuit and its operation. could you please tell me where we can get the out put . my mail id is .(JavaScript must be enabled to view this email address)

By Physics.Dude 0Score: 

4 years ago:  can i get some specifics on C1 30PF KEY=A 30%
like part #

By iron 0Score: 

3 years ago:  Hi last night i made the circuit in the multisim, in the output i have like 2uV and -100.5 dB in AC , in DC i have 3.6 V and 25.5dB,is this correct??


does anybody made the circuit and take values in the output??

By mayure deep oo5 0Score: 

3 years ago:   sir i very thankful you give me cell phone jammer
dayagram & parts list

























By muskan_90060@yahoo.co.in 0Score: 

3 years ago:  hi frnds mobile ke bare main

By ankit 0Score: 

3 years ago:   want to use it as my project ,please give me detail.how it work ?,component and price

By romeo 0Score: 

3 years ago:  the transistor MRF947T1 is unavailable in our market.... can you name any replacement for this component?? pls help me... tnx..

By kumsa 0Score: 

3 years ago:  i want about the winding of the coil ,diameter ,gauge to construct

By Mains 0Score: 

3 years ago:  There is lot of info missing: Part list, how to wind coils, what kind of antenna, replacement part!!

By maurice evans 0Score: 

3 years ago:  I think there has been some circuit which are able to detect that there are cellphone jammer in the area, have you heard about this guys?

By noggonen 0Score: 

3 years ago:  Maurice: try googling 'Gestapo'

By Ally 0Score: 

3 years ago:  Sir I Humbly Ask U To Mail Me All The Components Required To Make This Ckt,The Antenna Type , And A Detailed Explanation Bout The Working And The Components...Please I Would Pay U With My Life for being such A genius... Thank Ya

My Email: .(JavaScript must be enabled to view this email address)

By aaron gray 0Score: 

3 years ago:  is there any newer version for this? will it be possible to make this work on wi-fi?

By junaid 0Score: 

3 years ago:  1. i would like to use this as a project ,plz give me detail.how it work ?
2.mrf947 TRANSITOR not avible in marcket plz send equivalent

By kumaresan 0Score: 

3 years ago:  can i use MRF547 instead of MRF947

By proteek 0Score: 

3 years ago:  great friend this ckt really good
we want a jammer that can actually block all mobile & display freq & number of the caller so can u plz help us as we r left with few days for synopsis submision so plz send info as soon as u can
my id is .(JavaScript must be enabled to view this email address)
plz
thnx

By NEEDS HELP 0Score: 

3 years ago:  What is a substitution for the transistor in this diagram? It is very hard to find

By David 0Score: 

3 years ago:  reading the requests here it sounds like a bunch of towelheads looking for something free. They have no idea of american culture and do not care what others think of them!

By Dan 0Score: 

3 years ago:  how the hell do you want to use BC 547 for this project? http://www.bobtech.ro/documentatie/tranzistori.html here you have a catalog with transistors that are usually very common in any country. if you want to jam a phone that works at 800, 900, 1800, 1900, 2100mhz do not chose a transistor that works at 300mhz maximum... (like BC547)

By Omkar 0Score: 

3 years ago:  Nice simple circuit. Thanks for it. I am also from India and some are spoiling country's name. If you cannot built such a simple circuit, then what you are you doing in your BE EEE? Calling yourself electronics engineers but not able to build even this. This is final year project lol.

Thank the author for posting a schematic and you cannot expect him to personally send you details which has already been posted here!

By ashish jain 0Score: 

3 years ago:  can u give me the detailed description of this circuit as i want to use it in my project

By Rony -1Score: 

3 years ago:  some Indians are really making shamefull act here.. i m also an Indian.LITTLE stupid ones are .simply begging to the author for "more details" wht the hell u want more.? damn he has posed a lot for u here..!! he has given all all the details.. wht else u want him to say .? the fundamentls of electroncis for the stupid little engineers ..? dont spoil the name of INDIA AND STOP ASKING DAMN THINGS LIKE -- HELP ME.. HELP ME.. !!
not a single hell is here form my country who want to take the challenge .? every one want to hv details.. in the mails.. --is the author ur servant .? ass holes.. ask to ur faculties.. abt this.. ask to ur father who is spoiling money for u. .every samistor..ur relly nothing but a BULLSHIT..
NOW KEEP UR MOUTH SHUTTT AND START MAKING THE PROJECT.. work hard and find out form books and books and books..by tht way u will learn..intoi ur shit brain..
hope u all can UNDERSTAND ME.. and dont spoil OUR countries name..!!
--Rony

By superb!!!!! 0Score: 

3 years ago:  superb!!!!!!!!!!

By anderson 0Score: 

3 years ago:  i m not getting Transistor MRF 947 from the market,is there any equivalent transistor to this MRF 947

By Charles Bronson 0Score: 

3 years ago:  Whats the matter wif all dese stupid students - the bloody circuit is there, what more do they want? All foweigners as well.

By nabeel 0Score: 

3 years ago:  Thank for the Author
I advice the biginers enterested in this project by
the folwoing
use the same circuit to produse 88-108 mhz osillator
and pikup the signal by FM receiver
with BC547 transistor
hence you have chang the inductance
and some capacitance like c2 and use 20 pf
.(JavaScript must be enabled to view this email address)

By nabeel 0Score: 

3 years ago:  ??? ???? ?????? ??????
??? ???? ???? ????????? ?????? ??? ????? ?????????? ??????? ???????
????? ??? 88-108???? ????? ??? ???? ??????? ????? ??? 900 ????
???? ?????? ????? ????? ?????? ??????? ??????? ???????? ??? ?????? ??????
??????? ?? ???????? ??????? ??? 900????
.(JavaScript must be enabled to view this email address)

By firas 0Score: 

3 years ago:  it is soo nice

By fortune 0Score: 

3 years ago:  hello.everyone,we would like to intruduce ourself ,we are professioan manufacturer of cell phone jammers.if you interested our products ,we would like to get your reply.thanks

By rohit 0Score: 

3 years ago:  this is great project but,
where can i get to buy MRF947T1

By moorthy 0Score: 

3 years ago:  how wind the inductor

By ajit dhamankar 0Score: 

3 years ago:  send me all detail of simple mobile jammer using timer555

By Ramana 0Score: 

3 years ago:  i need a full details about this project

By deepak 0Score: 

3 years ago:  hey!
cn v use normal transistor here

By gurpreet 0Score: 

3 years ago:  sir plz tell me about the mobile jammer components and connection clearly and in detail and plz tell me about the L1 L2 sir plz.............plz.....plz...soonly

By niva 0Score: 

3 years ago:  whts the replacementfor mrf 947.......bc945 is fine?????????

By usa 0Score: 

3 years ago:  Here's an idea: you could combine this with a cell phone detector so that the jammer will activate only when cell phones are near it. That will save battery power.

By comments 0Score: 

3 years ago:  this is a nice project....
and a word to those who got irritated by seeing indians asking for details..(which they think shame 4 the nation)you r free 2 comment.....but should not hurt others..at the least should hav culture in your comments..pls..

By Ashar 0Score: 

3 years ago:  from where can i get the required devices to make this jammer and how much wil it cost approximately?

By Arcisure Engineering 0Score: 

3 years ago:  I took a look at the schematic and if im right, this device aint working for blocking a cell phone, because a cell phone has multiple frequency bands. this can bes solved using a 4017 uC, to automaticly change the capaciter value, and so the frequency

By majid 0Score: 

3 years ago:  hi this is a great circuit. I am using it in my mini project
but i need to know what is the type of the cell phone antenna ......???
pls replay

By mikle 0Score: 

3 years ago:  heey i cant know about antenna any thing .....
which type ??!!
what is the rang and CDMA or GSM

By WaqaR 0Score: 

3 years ago:  hey guys.. i hav just made up this project but cant get it to work...

got the exeact values for the inductor..
used bfw10 transistor.. insted of the mrf one...
n yes plzz tell me the detailz abt the antina...
plzzz

By Adnan 0Score: 

2 years ago:  Hi can i get an alternative to mrf947. Its not available in the market.

By alejo 0Score: 

2 years ago:  where find mr. Laszlo Kirschner , i need your help about this jammer

By Puneet jain 0Score: 

2 years ago:  I like it , we make this project

By zeeshan 0Score: 

2 years ago:  m from pakistan!
u can replace mrf947 with any npn transistor that has max frequency range about 2200Mhz or higher like mrf901, mrf517,
here is a link for a bunch of transistors , but select that one that has freq >2200 Mhz
http://www.datasheetarchive.com/pdf-datasheets/Databooks-2/Book249-5690.html
and also one indian said in this forum to replace it with bfw11
plz dont use that transistor as is has only 1Mhz freq range and also its not an npn transistor

and if any one ask about the detail about this project
plz dont say him as stupid or ant thing else

for those who still wants the detail:
read basic transistor biasing and working articles and little about 555 timer


By mustansar 0Score: 

2 years ago:  i am electronic engeneering student and i want to know the working of this circuit and hows we can jam all kind frequencies used in mobile phones and jam all kind of phones

By santosh 0Score: 

2 years ago:  can any one suggest me , were can i get MRF947T1 transistor in hyderabad.....

By praveen tripathi 0Score: 

2 years ago:  hello sir!which type of antenna i can use in this project;which is easily available in market?please tell me complete name of that antenna,so as i can barrow it from market;

By Ali 0Score: 

2 years ago:  can anyone please give me some details about the cell phone jammer i wnt to make it as my project

By Mexicannn 0Score: 

2 years ago:  Wow All of the information needed to build this circuit is here in the text. What other information do you need? its all in the schematic. I am amazed at how many people are baffled by this extremely simple circuit. And yes..... you can get these parts at radio shack. as for the 555 timer any electronics savvy person can locate one.

By Phy 0Score: 

2 years ago:  Thanks for the schematic. Saved me a day of trial and error experiments. Now I can kill signals when I really -want- them to be killed. Thanks again!

By arimardan 0Score: 

2 years ago:  i like this project

By Adam Eve 0Score: 

2 years ago:  For gods sake what the hell is wrong with people: Parts list is there, working of the circuit in there, google the parts list for datasheets, google for 'inductor calculator', why the hell are people so lazy? If you work in R&D, or are at UNIVERSITY doing a degree then you should already know what a varicap (trimmer cap) is, or how to use information in datahsetts to substitute transistors, or how to source a 555 timer, or how it operates as an oscillator.

So what the hell is it all about then? Why are all these people posting their emails on here? Is it a scam? WTF????

By Lad 0Score: 

1 year ago:  sir,I've done the stimulation and it working.I got 900MHz and above depending on how the capacitor is varied.I choose it as my project and I will be defending it next week.but my supervisor asked me to show him how and which components generates the noise.I thought both the noise and the triangular wave are generated from the 555 timer.I will be very grateful if anyone can help.Thank You.

By jeong 0Score: 

1 year ago:  Current Gain-bandwidth product of MRF947 is 8GHz (fT=8GHz).
If MRF947 is not available, check fT of Transistor in datasheet.

By CHANDRA SEKHAR 0Score: 

1 year ago:  Hi can i get an alternative to mrf947. Its not available in the market.

By East 0Score: 

1 year ago:  http://www.westfloridacomponents.com/T475PD/MRF947T1+MRF947+50mA+10V+High+Frequency+Transistor.html thats where you can get your mrf947. and if it doesn't ship to where you live just google mrf947.

By Basit Ali(BASITALI@WITTY.COM) 0Score: 

1 year ago:  m from pakistan....HFA3046, HFA3127, MRF 313 ARE THE BEST REPLACEMENTS AND WILL WORK PRETTY FINE IN SIMULATIONS....AND THE MOST COMMON AVAILABLE AND WORKING TRANSISTOR FOR MRF947 IS 2N5108......AND I M USING 2N25108......
EITHER OF THEM WILL WORK (INSHAALLAH)
I HOPE I HELPED YOU..

By hetali 0Score: 

1 year ago:  sir i am doing mobile jammer project, and i am not getting 1 IC maxim 2623 can u suggest me from where will i get that IC. and one more thing i have RF and IF section in that circuit diagram which are difficult to design, so can u help me in dat to get that pcb board readymade..

By muralirajana 0Score: 

1 year ago:  i want know for how much distance it jamm

By Fakhrealam 0Score: 

1 year ago:  hi i ma telecom student i want to complete my mini project mobile phone jammer so that i kindly request you to help me

By arshad multan 0Score: 

1 year ago:  thanks very good project

By drochalsey 0Score: 

1 year ago:  Nicely simple and effective circuit, Laszlo.
Do you (or anyone else, for that matter) happen to have any suggestion for interfacing it (the circuit) with US, 110-120v AC, house current, as a "current subcarrier transmitter" so that I can turn the "hot" line in my whole house into one big (short range) cell-phone-killing antenn (i.e.: turn my house into a "cell phone NO-FLY Zone?")
I'm not worried about the neighbors as the signal will NOT carry (RF-wise) to their houses, NOR will it be able to go past the "isolation transformer" on the pole.
Thanks in advance,
drochalsey (a.k.a.: .(JavaScript must be enabled to view this email address))

Bharath Yv
By Bharath Yv (0) 0Score: 

1 year ago:  I have the following queries:
1. how to get 1nH and 2.2nh
2. suggest suitable replacement for MRF947.

Bharath Yv
By Bharath Yv (0) 0Score: 

1 year ago:  I have the following queries:
1. how to get 1nH and 2.2nh
2. suggest suitable replacement for MRF947.

E-mail me at .(JavaScript must be enabled to view this email address)

Qasim Riaz
By Qasim Riaz (0) 0Score: 

1 year ago:  hEllO tO EvEry OnE...!!!!
If Any pErsOn 'vE mAdE thIs prOjEct And wOrkIng prOpErly , thEn plz cOntEct mE thrOUgh E-mAIl...



.(JavaScript must be enabled to view this email address)

H B
By H B (0) 0Score: 

1 year ago:  see thise web:
http://www.instructables.com/community/XKCD-tries-its-hand-at-circuit-design/

the funniest is L=1nh!?

it's difficult to buy mrf947 and if you want to use any thing else you should designing Impedance matching network yourself (c4-c3-r2-r3)so ...

"YOU CAN NOT REPLACE IT!?"

i say it to all clever's who say's taht indian is stupid"

H B
By H B (0) 0Score: 

1 year ago:  how's you'r idea Rony??

Elias Shija
By Elias Shija (0) 0Score: 

1 year ago:  i need to do this project in my studies because its a good one,so how can i get a data sheet because i had failed to identifies the values of the voltage of the capacitors and resistors because in the diagram you mentioned their percentage.

Graham Ryan
By Graham Ryan (0) 0Score: 

1 year ago:  I ordered all the parts from Mouser, including the elusive inductors. I will post the results once I get this built. I also will be using a chip antenna, so that should be interesting to see how it works.

H B
By H B (0) 0Score: 

1 year ago:  you need pcb layout because it's a Frequency circuit and it will not work on breadbord,First you should protel it.you can have many different pcb layuot for these diagram but only one of them would work so...
"YOU CAN NOT BUILT IT FROM DIAGRAM".
?!?!

Richard Percifield
By Richard Percifield (+10) 0Score: 

1 year ago:  While this circuit will work, C4 as an electrolytic cap will limit the modulation bandwidth. The self resonant point varies with the capacitor, but most electrolytics start becoming more inductive at about 30-70KHz.

Also, using the base as a mixer will work, it is not the most effective method. Another issue is output loading on the antenna will affect tuning of the circuit as well. Thus, placing your hand near the antenna will shift the frequency.

As someone said above the only way to build this is on a PCB or RF breadboard with surface mount components. Otherwise, the parasitic capacitance and inductance would be too great and load the circuit. Another possibility would be to use resonators to set a frequency and mix the output with the modulating signal to obtain a stable signal, better controlling the output.

YVES SOUSSI
By YVES SOUSSI (0) 0Score: 

1 year ago:  Dear Sir

1) MRF947

We are a eBroker of electronics parts - We have a stok of transistors MRF947 , new and original. We sell in small quantities and accept PayPal

Our Web sites = http://www.penuries.com - www. RFQ-HotStock.com

br
yves soussi

Ben Marlin
By Ben Marlin (0) 0Score: 

1 year ago:  Please email me a parts list if possible @ .(JavaScript must be enabled to view this email address) and if not tell me how to make the 2.2 nH inductor and 1 nH inductor

Rogelio Ferrer
By Rogelio Ferrer (0) 0Score: 

1 year ago:  Good day! Mr.Richard Percifield can i ask some help with the circuit? By the way i am a electronics student and i am planning to use it on my research. can i use a radio antenna instead of cell antenna? and please could you send me an your modification on the schematic diagram of the circuit? Lastly is it possible to amplify the Rf signal coming out of the jammer? my e-mail adress is .(JavaScript must be enabled to view this email address)

Gihan Senarath
By Gihan Senarath (0) 0Score: 

11 months ago:  Sir i think this is a great project . so pls send me the full project report to .(JavaScript must be enabled to view this email address)
Thank u sir

trishita Dey
By trishita Dey (0) 0Score: 

7 months ago:  sir m thankful to you that u have created such a convenient jammer circuit but am not able to understand the working principle of it....ill we highly oblized f u pls send me the working theory...my email address...
.(JavaScript must be enabled to view this email address)

Abel Silut
By Abel Silut (0) 0Score: 

5 months ago:  i like this circuit.please send me the note that describes principle of operation of this circuit.my email address is .(JavaScript must be enabled to view this email address)

sreejith Mohanasundaran
By sreejith Mohanasundaran (+1) 1Score: 

4 months ago:  Sir ,
I am a pre-final year electrical engineering student.
I would like to make a mobile detector with jammer. so can you please send me necessary details. so that i could work on and make my project a sucess
My id is .(JavaScript must be enabled to view this email address)

trishita Dey
By trishita Dey (0) 0Score: 

4 months ago:  sir i also want make that detector of any mobile present in a certain range of area can u please send me sum circuit diagram n can help me out....
my email id:
.(JavaScript must be enabled to view this email address)

Asheet S
By Asheet S (0) 0Score: 

3 months ago:  Dear sir,I'm interested in making this project for my pre-final year project.Can you please send me the detailed report on my email ID - .(JavaScript must be enabled to view this email address)

Utkarsh Bais
By Utkarsh Bais (0) 0Score: 

3 months ago:  What we can use here in plca of MRF947 npn transistor plz help me bcose i am not geting it here, plz help me

Christian Omeje
By Christian Omeje (0) 0Score: 

4 weeks ago:  Why do u post circuits that u hv nt tested that doesnt work ooh this circuit can never work

Christian Omeje
By Christian Omeje (0) 0Score: 

4 weeks ago:  Guys dont waste ur money it can never work

Ricardo Kaka
By Ricardo Kaka (0) 0Score: 

1 week ago:  Can I use bft66s1 instead of MRF947t1
And the other thing is I am exhausted of finding or making the 1n and 2.2nH inductors. These are not easily available and due to such a low value I found Almost impossible to make it with my own hands.

I have read somewhere that transistors can be used in proper configuration to get the same results like inductors.

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