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Mobile Jammer Circuit Antenna Selection

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PoS080

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Mobile-Jammer-Circuit-Diagram.jpg

Hello EEs,

I found this cool mobile jammer circuit project online https://www.electronicshub.org/mobile-jammer-circuit/, and I would like to create it for a school project. I am familiar with all the components except the antenna. I grabbed my Electromagnetics book, and it goes over different types, but im unsure as to which type I need.

I plan on purchasing all the caps, resistors, and transistors and making my own inductor. Can anyone guide me about what kind of antenna I need? Do I need to make one or can I purchase one from mouser or digikey? Any ideas?

Respectfully,
An EE in training
 

So after reading through all the comments I noticed that the antenna seems to be a Yagi Uda. Anyone familiar with these? I will read about them in the meantime.

Thanks!
 

It's all bull-crap. For one thing, it's supposed to be a "mobile" jammer, but with a Yagi antenna, you would have to physically track the receiver you wanted to jam - not very efficient. If the antenna was more omni-directional, you would need to increase the TX power to force all receivers in the unit's range into saturation. Also, this thing is illegal in most jusidictions.

If you really want to jam mobiles in your area (illegally, of course), a simple spark-gap transmitter is wideband enough to swamp 99% of all receivers in an area.
 
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    PoS080

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The BF494 transistor is old, obsolete and not available any more. It is NPN but the schematic wrongly shows a PNP.
The capacitors C2 and C3 (why 2 capacitors instead of one 10pF?) from the collector to the emitter cause positive feedback and oscillation but C5 wrongly applies negative feedback which stops oscillation. It would probably work if C5 is removed.

Cell phones operate at many much higher frequencies so maybe this circuit is useless.
 
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    PoS080

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Oh wow,

Thanks for the heads up. I will not be attempting this circuit then. I will look for a new circuit, but I would still like to build a jammer circuit with a much smaller radius.

Do any of you have any practical experience building something like this or have any circuit schematics?

Respectfully,
PoS080
 

Maybe you are in a country that uses one very old mobile phone radio frequency.
Modern cell phones use many frequencies. If you jam one frequency then the phone and tower will simply switch to a clear frequency.

Cell phones can be used to call the police, fire department or an ambulance. If you jam them then you might kill people.
 


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