I was there in an exhibition yesterday. Most of the times, i was not able to use my cellphone data internet. But, i was able to make calls with the phone most of the times. Now, i have a doubt here. I happened to call a friend who was also to the same show, and he did say that he was not able to access the cellphone internet there. He said that they had used Network Jammers, though he was not certain about it.
My question here are: 1) Can network jammers only restrict data and not calls? How is it possible??
2) Will there be separate jammers for 2G/3G/4G/5G, based on it's spectrum?
3) Are jammers free of health hazards?
4) What could be better designs to use than jammers?