There are several types of jammer. It could interfere the signal of any electric or electronic device. It is a violation of federal law to use a cell jammer or similar devices that intentionally block, jam, or interfere with authorized radio communications such as cell phones, police radar, GPS, Wi-Fi etc.
|Is it legal to buy audio jammer from Spytec?|
Is it worth to buy and use portable jammer?Humphreys from Florida was fined $48,000 for driving around with phone jammer in his car.
It's not worth to buy a $200 or $300 of jammer and get fined $48K after using it. Even if the portable jammer can be purchased lower than $100, I don't think it's worth it.
It's not cool to interfere the phone's signal, wifi, camera etc. What happen if there is emergency but nobody can call for help? Please don't use jammer even for prank.
There are many ways of fun prank. You could still use spy gadgets for fun. Just stay away from portable jammer unless you are authorized to use it.
P/s : Device jammer is easier than device detector.
FCC - Jammer Enforcement.