RF Detector/ Mobile detector

[CircuitMan]

Anyone got a good circuit for a bug/mobile detector. Basically rf signal detector, help me please

 

[audioguru]

If you don't specify a band of frequencies, it will pickup every radio or TV station, taxi or police car etc. in town. Of course, instead you could make an "all frequencies" bug detector have a very low sensitivity. Then it won't pickup the bugs unless it is very close to them, or the bugs broadcast a powerful signal (unlikely).

 

[zachtheterrible]

heres a circuit that you could use. you could adjust the sensitivity by adding a little transistor amplifier to it. ask someone else about that cuz i dont have a clue. i think that you could probably get it to sniff a bug within 10, maybe 20 feet without picking up other signals (unless of course you have a wireless intercom or something). im totally guessing though. make sure u keep that capacitor in there. i think its there so that it wont pick up mains electricity.

the dvm + n - go to a voltmeter (i recommend a digital one), and the ground is supposed to be connected to the thing that you're testing, but obviously you cant do that because you are looking for the transmitter. but you dont have to do that, doing that just increases the sensitivity. here it is:

 

[CircuitMan]

I want something like this:

**broken link removed**

more infor needed!

 

[audioguru]

It is obvious that with such a high price, that detector must have many, many parts and is probably too complicated to make yourself.

 

[CircuitMan]

Ok yeah but I want a simple version of this forget all the other bits like lights sound i just want the detection part!

 

[jrz126]

Those extra bits are the simplest things on there, the detection is super complicated.
Cell phones use a wide range of frequencies, so it's definitly not an easy answer.

 

[timothyjackson]

Hello Circuitman

have a look at:

**broken link removed**

You could buy one, take it apart and understand it that way.

Take care

Timbo

 

[AndyWatson]

I recently built a RF detector device, complete with Basic Stamp, LCD display, 2-stage LNA amps, selectable filters, mixers, microprocessor-programmed frequency synthesizer for generating the LO, an RF detector, and a directional antenna. You can select narrow or wide bandwith (5 to 20 MHz) and any frequency from 750 to 1800 MHz. It's got really good sensitivity and can pick up cell towers from several miles away. The entire package cost around $800 and took about 6 months to develop. Unless you have alot of time and expertise, I suggest you buy a commercial device.

 

[zachtheterrible]

Wut about that circuit I posted? I think he just wants to pick up bugs, and that would work pretty nicely if a little amplifier was added to it right? Then you just adjust the sensitivity of the amplifier. Just get a high speed diode tho :lol:

 

[CircuitMan]

I want to pic up mobile phones, dont care about bugs or other radar gear.

I found something good:

http://www.elektor-electronics.co.uk/miniproj/frmipro.htm

Not sure if this will work as it looks cheap, need to modify it someway so that i can get output as a light and sound no headphones. :?

 

[jrz126]

that might do what you want, but it probably wont work as good as that other one.

here's a better url for it **broken link removed**

 

[zachtheterrible]

I want to pic up mobile phones, dont care about bugs or other radar gear.

Oh

 

[mansoor_ahsan]

hi i am doing my final year project of RF detector and jammer frequency range 1MHZ to 3GHZ kindly any one help me if any one have circuit digram or any matlab code for frequency detection and jamming plz help