what about this guys? do u think this would work?

Elektronika.ba - GSM sniffer circuit schematics

 

The simple circuits might pickup every TV station and every taxi-cab radio in town.
The GSM sniffer is just a simple crystal radio with an audio amplifier.

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Uncle $crooge

 

A Field Strength Meter Using A Biased Schottky Detector. One small PCB for the detector, which responds to frequencies through 2.4 GHz (works great with microwave oven)




Field_Strength_Meter_FSM_With_Schottky_Detector

 

I'd like to, but I can't imagine what you actually need. It seems, and correct me if I'm wrong, that you want to snag some kind of circuit off the internet that you can build and pass it off as some kind of project for some kind of credit in some kind of course. I personally don't think that this activity will be very beneficial since becoming intimately familiar with the operation of and theory behind the circuit seems almost incidental to your purpose. You might as well build an HHO generator and claim that you've solved the world's energy problems. Then defy your instructor to prove you wrong.

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We never have time to do it right; but we always have time to do it over.

 

That circuit you posted is garbage. Forget about it. Find a different project that you can copy from.

__________________
Pay it forward.

 

Maybe something from the Aaron Cake site

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Actually we just need to pass a working project in order for our school to release our trancripts!!! That's our problem actually, we're very familiar with the theory but we can't apply it. I know what you're trying to point out. But this conversation is already pointless since we know it's our FAULT! you can preach all you want but sh*t happens. you just can't do anything about it and that only leaves you to turn to people like you who could help. i hope you understand me.

 

Thanks man. just what i need.

 

HAIL Dick Cappels. you're my savior man. starting right now, you're my GOD! thanks for the project man!

 

i'm having a problem right now. since the ckt below could only detect one frequency band, what should i do for both 900Mhz and 1800Mhz? should i just add a coil parallel to it?

Mobile Phone Sniffer - ELEKTOR.com ? Platform for electronics and microcontrollers

 

Despite your grasp on theory which you "can't apply", a coil in parallel will not do the job. A second coil and a DPDT switch might do the the job.

__________________
We never have time to do it right; but we always have time to do it over.

 

No No the Aaron Cake site has awful projects, I meant it as a joke!

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

I think that these cell phone detector projects are very old. Maybe the circuits were designed long before cell phones were invented. No wonder they do not work.

They might detect a cell phone when they are touching, then the RF will overload the input of the opamp.

__________________
Uncle $crooge

 

Just imagine the embarasment of "detecting" a cellphone only to find that the alleged perpetrator doesn't even own one. That's a surefire cure for sticking your nose where it doesn't belong.

__________________
We never have time to do it right; but we always have time to do it over.

 

That was a joke too... i saw the site man. awful.