disclaimer
Note, this activity is illegal in the US and most other countries.
I am NOT suggesting this, HOWEVER wouldn’t it be interesting to have one to blank out the butt who chatts during the movie ?
Or the dummy who is nearly rear-ending folks while texting/talking ?
I like technology, just wish people would use “good-judgement”
http://en.wikipedia.org/wiki/Mobile_phone_jammer
I want this as a bumper sticker, [if I used them]
BTW, Saturday night two weeks ago, I saw a young girl turn in front of a motorcycle, he smashed into the side of her car, breaking 4 ribs and his right wrist.
As she came to rest, I saw her face illuminated with the phone she was holding in her right hand.
I became enraged, used language usually reserved for the Navy.
I got one, but never did get it calibrated correctly.
If someone can verify they work, I want one. Could have so much fun with one.
I want one! Legal to own but not to use. ;_;
It should have calibrated from the manufacturer. Very few people would have the equipment for that.
Can you know its bad calibration vs poor construction / defective?
“France legalized cell-phone jammers in (movie) theaters and other places with performances in 2004. Abandoned due to complaints regarding emergency calls. Still legally used inside jails.”
These things emit alot of powerful waves, its bad for your health, especially in your pocket.
Mine is a bit older. It has pots to adjust it. There's no practical way for me to know if it's defective that I'm aware of.
I have one from manafont, in cigarette packaging.
It actually works but the range is not good.
In a meeting room, phones in 1-2 meters do not work at all,
other phones gets difficult to talk but works.
it is not possible to jam all phones in a movie theater.
You need something with huge antennas and power supply.
So you can not conceal it.
And it is also illegal to use personally.
Some mosques (muslim worship place) tried to use bigger jammers,
but because of the law they are all shut down.
Thanks, fyesilova. So for it to be useful it would be unpractical. I would also be concerned how it could affect emergency services.
The intended usage originally was to block GPS tracking, only later did jamming become popular [afaik]
Range is typically low, “Effective range: 3~15m”
Of course, any transmitter, especially high frequency, can be considered hazardous to health.
Just build a spark gap transmitter.
The higher power the better.
Which will kill all RF stuff from 1kHz to 10GHz.
The recipes are out there. But the power usage will be significant.
this 
For a moment, I thought that your signature was a pic of an example of a “huge antenna” that you mentioned :)…
The intended usage originally was to block GPS tracking, only later did jamming become popular.
Do they block GPS tracking?
I would assume so, given the typical [read non-govt] GPS trackers very limited output wattage.
FYI, some “buy-here pay-here” car lots install GPS tracking devices with the buyers knowledge and consent.
That’s not an antenna as I guess you have found out,
in fact it is one of the bridges that connects europe and asia continents.
There is night time lighting and can change colors.
I think it should be easier to block gps, because the signal is very weak, comparing with mobile phone signals.
This type of device can and will interfere with emergency calls, the reason for the being banned in a lot of countries.
my office got one of these jammer on meeting room 
maybe i’ll lock the door and trip the alarm J)
I need this, but for cell phone frequencies.
