Cell phone and WiFi jammers!

[Trace]

How well do they work? And are they legal in the U.S.A.?

Does anybody have a schematic for either?

I can buy a cell phone jammer, but was wondering if it could be built cheaper. And I have found a way to make a WiFi jammer but it is not very powerful.



How to build a WiFi jammer video:


<embed src="http://www.metacafe.com/fplayer/953946/how_to_build_a_wifi_and_bluetooth_jammer.swf" width="400" height="345" wmode="transparent" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash"></embed><br/><font size="1">
<a href="http://www.metacafe.com/watch/953946/how_to_build_a_wifi_and_bluetooth_jammer/">How To Build A WiFi And Bluetooth Jammer - video powered by Metacafe</a></font>

[Drum Thumper]

Very much illegal to own in the United States.

[Trace]

Why did I expect that from the U.S. government

[xRyokenx]

I'd love to have one of those if I ever teach... I wanted one when I was in highschool too, random people texting during class was annoying. Too bad it's illegal. Stupid government. They can take **** away but when we try to say, watch a movie in peace, it's not allowed.

[Quakken]

It's all for the illusion of freedom.


But, a cell phone jammer would definitely be a clear violation of the bill of rights, such as right of free speech. It would be like making it impossible for people to whisper in the theater.

[Trace]

Yea, I guess so. Yep, I'm in highschool and thats what I wanted it for. And so does 1 of my teachers haha
France just legalized it for use in theaters :D

And, they can talk all they want in person. I'm not stopping them, but if I could stop the phone, that would be nice. I don't see how it "exactly" violates the bill of rights :p

[mtekk]

Very much illegal to own in the United States.

I'm not sure if possession is illegal, but operation is definitely illegal without a FCC license. Optimal solution, take the FCC classes to get the license, which also allows you to use higher powers and more frequencies for FRS and GMRS 2-way radios.

As for jammers working, yes they can. The one they "made" there takes advantage of 2.4Ghz band that 802.11b/g/n and bluetooth uses. Some phones will mess up networks with normal use. Their mod just creates a possibly better antenna, however their suggestion that a Dual Layer DVD will work better than a CD has little to no theoretical backing. I find that an improperly shielded microwave makes a much better (and dangerous) jammer for the ~2.4-5Ghz range. I really never trust a thing I see on metacafe, there seems to be an ongoing make stuff up and present it as fact trend that goes on in it.

If you build one yourself, and only use it occasionally (for educational purposes of course), I doubt they will ever catch you. You can find instructions online for making one. You'll need several radios and a microprocessor to control everything, looks ripe for a PIC (which you can get a free sample from Microchip). I think Hackaday had something on this a while back (like two or so years ago), might be worth looking at that.

[mtekk]

Oh, I found the article, it's on Wave Bubble (http://www.ladyada.net/make/wavebubble/index.html).

[Trace]

Thanks guys! I have been google'ing around and didn't find much. Looks like just what I need.

[crenn]

The 'device' in the video isn't a true jammer, but it will interrupt communication and act similar to a jammer.

[Bopher]

You don't know how much I would love to install on of these on the back of my Wendy's. People constantly come into the DT lane on the phone. They get all annoyed when we ask to help them. When they get to the window I talk to them like they aren't on the phone. A jammer would be nice though if it was legal of course.

[Drum Thumper]

When they get to the window I talk to them like they aren't on the phone.

I do a similar thing at work--if you come through my checkstand and you're on your phone and I don't know you, I crank the 'annoyance' factor up a bit by raising my voice a few decibels. I've yet to have someone get pissy with me over it--most people apologize.

[xRyokenx]

If I'm getting food or something I tell the person on the phone to hold on. I hate talking to two people at the same time, it seems impolite to both of them, especially so to the one that's not the one on the phone.

[chaksq]

People do abuse cell phones but if someone set up a jammer for my phone or wifi there would be some serious trouble.

And Ryoken thats exactly how I feel about it. If my phone rings sometimes I dont answer it and then call the person back 5min later when I'm no longer doing what I was doing.

[Airbozo]

The law that makes jammers illegal dates back to the '40's. It is a law designed to prevent people from indiscriminately broadcasting interfering signals. It was a necessary law at the time to allow the government to restrict the use of the airwaves to those with a legitimate need.

It does not matter if you take any FCC test, devices designed to _actively_ interrupt any sort of electronic signal are illegal to use in the US. Unless you are the military or government. There are passive ways to block a signal that do not violate any laws (it has nothing to do with free speech since you are free to say what you want when you want (unless it promotes panic or violence (such as yelling fire in a crowded theatre)) because you do NOT need a cell phone to practice free speech).

My brother in law looked into passive cell phone blocking for his theatres, but it California it is illegal to use the sort of paint he needed due to the chemicals (probably lead) in the paint.

This is another example of passive devices that do not violate the US Communications Act;
http://www.wired.com/techbiz/media/news/2002/06/53538

[xRyokenx]

Oh yeah, another thing that came to mind, I have my phone so it only vibrates. I hate the default ringtones, I'm the only person that needs to know when my phone is ringing, and I despise contributing to noise pollution. It's a luxury to have a phone, not a need... well, not yet anyway. It's like another thing that's not a right, don't abuse it and people won't make stupid laws ruin it for everyone else, lol.

But I guess that goes with anything though.

[Omega]

One of my classmates made one =p

It was interesting, to say the least.


Also, I'm pretty sure you can own and operate one with a proper FCC license. But that's pretty much how it is with anything so =p

[Airbozo]

One of my classmates made one =p

It was interesting, to say the least.


Also, I'm pretty sure you can own and operate one with a proper FCC license. But that's pretty much how it is with anything so =p


There is NO FCC license to operate a jammer. "." The ONLY entities authorized to operate any sort of signal jammer are military and government authorities (and defense contractors operating with the Fed's knowledge in a facility that will prevent the signal from leaking out). Then even the Military has to show due cause to operate any signal jammers within the united states out to 12 miles off shore (I do know this for fact since my job in the Navy was "Electronic Warfare" and the jammer on my ship was powerful enough to burn the paint off a ship at 1/4 a mile).

That said, to date no one has been convicted or even charged with operating a cell phone jammer. Yet.


The FCC notes on its website that all persons "operating or using radio transmitters must be licensed or authorized under the Commission's rules," and that the FCC does not authorize the "operation of any device specifically intended to interfere with cellular communications." (43) Additionally, the website warns that Title 47 of the United States Code specifically prohibits "willfully or maliciously interfering with ... radio communications...." (44) Although these laws are part of the Communications Act of 1934 and do not specifically contemplate cellular telephony, the FCC nevertheless advises that parties who operate "transmitters designed to jam cellular communications" are subject to the punishments described in Title 47, which can "range as high as $11,000 for each violation or imprisonment for up to one year."

OH and I got my dates wrong, it is the "Communications Act of 1934" that prevents jamming.

[mtekk]

...the jammer on my ship was powerful enough to burn the paint off a ship at 1/4 a mile...

That would be one hell of a jammer. The real question is, how far away could you cook the Thanksgiving turkey with that? :twisted:

Classical jammers are really a waste of power. Now a cool jammer would do a similar thing as Comcast does to bittorrent users. Send out disconnect packets (tell them the cell channels are full) to the active cellphones. What's cool about this is your jammer can be "passive" most of the time just listening for communication, once it's found it can send a disconnect signal, ending the call. It'd be a heck of a lot more complicated but so much cooler. It'd probably still be illegal by that communications act (which if it is then Comcast's actions would be by the same law as we are taking about packets of information here not strictly limited to over the air transmission).

[Airbozo]

That would be one hell of a jammer. The real question is, how far away could you cook the Thanksgiving turkey with that? :twisted:

That's what the fire control radar was for...

Classical jammers are really a waste of power. Now a cool jammer would do a similar thing as Comcast does to bittorrent users. Send out disconnect packets (tell them the cell channels are full) to the active cellphones. What's cool about this is your jammer can be "passive" most of the time just listening for communication, once it's found it can send a disconnect signal, ending the call. It'd be a heck of a lot more complicated but so much cooler. It'd probably still be illegal by that communications act (which if it is then Comcast's actions would be by the same law as we are taking about packets of information here not strictly limited to over the air transmission).

The law covers only the RF transmission portion not the signal in the cable.

That is a good idea though. It is similar to some radar jammers that intercept the signal, mix it with another higher strength signal then send it back out at the same frequency. I saw this in action on one of the gadget shows out of the UK. When the police officer, looks at his detector, it shows something like 18 mph instead of the 130 you were actually going. Similar to the function of the jammer on my ship. If we wanted to attract the missile away from the Carrier, we tricked the missiles radar to make it believe WE were the bigger ship.

[Twigsoffury]

Not sure if i already said this,


But my microwave makes me and everyone else in the house loose wi-fi signal, cell phone calls and other wireless devices (even xbox controllers)


I'm thinking i might need to replace that 1980's microwave, but it cooks burritos like a hydrogen bomb.

[Drum Thumper]

Not sure if i already said this,


But my microwave makes me and everyone else in the house loose wi-fi signal, cell phone calls and other wireless devices (even xbox controllers)


I'm thinking i might need to replace that 1980's microwave, but it cooks burritos like a hydrogen bomb.

I'm surprised it cuts cell phone signal, I will say that.

However, I am not surprised that it mucks up anything on the G band. I lose connectivity in the kitchen and master bedroom if I vacuum the living room.

[Luke122]

Yea, I guess so. Yep, I'm in highschool and thats what I wanted it for. And so does 1 of my teachers haha
France just legalized it for use in theaters :D


You ever see that guy in the theatre who turns around and yells at the people with the phones, to shut the f*ck up or leave?

Yeah, that's me.
My wife was so embarassed the first time I did it, but a ton of people were cheering as the person stomped out all mad.

[Twigsoffury]

I'm surprised it cuts cell phone signal, I will say that.

However, I am not surprised that it mucks up anything on the G band. I lose connectivity in the kitchen and master bedroom if I vacuum the living room.



I think yall under estimate just how crazy this microwave is.

[OvRiDe]

Darren Kitchen recently demonstrated the interference caused by a microwave oven using a wifi spectrum analyzer on HakTips.

cYDLxNatI54

Jump right to 5:20 (http://www.youtube.com/watch?v=cYDLxNatI54&feature=player_detailpage#t=318s) to see the analyzer output.

[Airbozo]

You ever see that guy in the theatre who turns around and yells at the people with the phones, to shut the f*ck up or leave?

Yeah, that's me.
My wife was so embarassed the first time I did it, but a ton of people were cheering as the person stomped out all mad.

That was me cheering and clapping.

My brother in law owns and operates a string of movie theatres and he has signs up making sure people know that if they use their cell phone during the movie, they will be kicked out with no refund. He looked into using a jammer until he found out they were illegal. Then he found a product used in many theatres across the country to passively block the signal. A company makes sound deadening panels lined with a layer of tin foil (or something similar) that, if installed correctly, will block all cell signals. After speaking with his lawyers concerning possible lawsuits if people cannot reach 911 in case of emergency, he decided to not install them and instead monitor the use of cell phones in his theatres.

[Twigsoffury]

That would be called a Farady cage.

He could also place emergency phone boxes inside the theater rooms as well as fire extinguishers (those should already be available by the way) and over shoot the need for people to have cellular devices in a emergency situation since a dedicated emergency phone is already on the premises, people and emergency codes existed well before cell phones, take a look at the code books or just call your local non emergency fire department line and ask for a fire inspection visit and see how your bro in law can meet code requirements and solve the issue with cellular devices

but anyways...

a farady cage is the same deal thats used when people step in that cage at shows and tesla coils shoot lighting bolts at the cage with the person inside but magically they aren't harmed!!1!!1

http://en.wikipedia.org/wiki/Faraday_cage

But you can also use that cage and place a electronic item inside and maintain a very low level of interference. works great for Audio/Video equipment if you want the best possible picture and audio possible but there are tons of other ways to use it.

http://www.jeddaniels.com/wp-content/faraday_cage.jpg


Basically at its heart all it is, is a grounded piece of metal. and i think it works by making all the passing waves give its energy back to a earthen ground instead of the material passing the energy forward sort of like a sound wave.


[edit] lol at the bottom of the wiki page is listed


The cooking chamber of a microwave oven is a Faraday cage, made to contain the RF signals of the cavity magnetron which cooks the food.

Mine must have a faulty ground from the cage? I wonder if my contact is corroded or its become loose in some way?

Maybe that is the problem with all the problem microwaves is a faulty path to ground?

Hold on mother f@#kers i'm going downstairs and checking my ground on the outlet and see what sort of resistance i get from it.

[Kayin]

Look up Tempest shielding sometime. I'm still trying to get the hardware for it. THAT's killing a signal.