Jammers don't target individual phones - they actually block all phones in the affected area. They drown out communications between cell phones and base stations by generating RF noise - the equivalent of you trying to talk to someone while I'm standing next to you screaming at the top of my voice.

I doubt anyone is using jammers - jammers are uncommon, and the penalties for using jammers are quite severe in many places. Start by talking to your mobile carrier. If after all of this you still have reason to believe that jammers are being used, complain to the body responsible for radio and communication systems in your country - this could be the FCC in the US, or Ofcom in the UK - other countries will have their own equivalent.

Someone used a signal jammer on me. How do I find it and stop it?

I thought it was the same at my house where the signal was always down to 3g and I couldn't use the service unless I was outside. It turned out to be an IMSI trap installed in the apartment next door. I started getting phishing pages from my bank and realized that my email had been compromised, the virus software on my computer had been disabled, and everything I did had been copied because it acted as MITM.

How to prevent jammers?

This happened to me at the school where I worked. Now, a private company has rented the school building to conduct the exams. As previously agreed, in order to prevent rampant unfair practices in public exams, the company installed jammers in all 108 classrooms of our school. This was done a few days before the exam. Children are curious and mischievous by nature. One morning, we found that none of our smartphones on or off campus had received a signal. Several departments at a university next door were also affected. It's almost impossible for us to find the malicious jammer we suspect is at work. Fortunately, however, the school LAN as well as Internet connections and landlines are working. As head of technology, I had to come up with a solution, and today I'm going to share that solution.

Compared to GSM 4G cellular networks, Wifi uses a higher frequency (2.4 Ghz). The trick for all users with a phone that supports WiFi calling or VoIP is to route calls through the WiFi network. For other users with smartphones, the solution is to use Whatsapp to talk to FBM (Skype works too, only no one uses it except me).

This went on for a few days, and after the test was over, the renters left with their jammers.

Have you ever secretly used a cell phone blocker in a restaurant, theater, or on public transportation to end an unusually loud, obnoxious, and unnecessary phone conversation with a stranger sitting next to you?

I once rode the quiet Amtrak car between Boston and New York.

A woman was on the phone, completely oblivious to the signs posted and the announcements made over the public address system.

She replied, "The train hasn't moved yet," and continued the conversation.

From now on, all I have to do is ask the conductor for help, even if he's sitting next to me. I've gotten too many smart-aleck - or worse - replies.

Once, at a movie, I asked a young woman next to me to turn off her lit cell phone, and she reported me for harassment.

God, I'm easily twice her age, but that obviously doesn't count.

How to use cell phone jammer? Where can I buy one?

To use this phone number, first make sure you have the lawyer's phone number on hand - it is illegal to use a lawyer's phone number in most countries.

It's easy to find them online - try Google, but you'll have to check if they're allowed to be imported into your country. It's easy to find unsophisticated devices that broadcast across the entire spectrum (kind of like sparks, but more sophisticated), but this would obviously annoy more people and authorities even more, not least because it would block 911 calls and potentially also communications for emergency services, WiFi, Bluetooth, etc.

If you want a device that allows 911 calls but blocks other calls, it's very complicated and expensive. In addition, as more and more frequencies (from about 800Mhz to more than 3GHz) are used in cellular networks, these devices must cover a range of radio spectrum.