For a simple cell phone jammer that will knock out the cell phones of the students in a classroom, you need a jammer that is very large or strong. In fact, you can likely use a pocket jammer, which looks like any ordinary cell phone, to keep the cell phones quiet in your classroom.
Why is this important? Well, presumably a Southern invasion would require some sort of GPS signal for logistical coordination. However, I seriously doubt the satellite signals available to both military and civilian devices aren’t being bolstered by some secret system that we don’t know about. I mean I love my Forerunner and all, but I wouldn’t go into battle with it.
When someone hears about cellphone jammers, you might have an initial overall negative impression. After all, why would someone want to cut off the communication of cell phone users? The reality is, there are really many reasons to consider using a cell phone signal jammer — and within a variety of settings.
Richard Langley, a professor of geodesy at the University of New Brunswick in Canada, said the GPS jammer would also have a hard time interfering with an encrypted military GPS code broadcast at a frequency of 1227.6 MHz. But the jammers could interfere with signals broadcast at 1575.42 MHz, a band used by commercial GPS receivers. Such receivers could have been bought by individual troops, but the Army tried to derail that practice in January.
Presently, the mobile jammer devices are becoming civilian products rather than electronic warfare devices, since with the increasing number of the mobile phone users the need to disable mobile phones in specific places where the ringing of cell phone would be disruptive has increased. These places include worship places, university lecture rooms, libraries, concert halls, meeting rooms, and other places where silence is appreciated.
Vulnerabilities exist at all levels in all areas. Criminals have already learned how to compromise RF tracking systems of cars, containers and other cargo. Rigs and drillships exchange massive amounts of RF data with shoreside partners to conduct operations. State and non-state actors, including hacker organizations, have vowed to attack all forms of energy production worldwide. RF jamming has intensified globally. North Korea has proven the effectiveness of long-range jamming by its relentless attacks on South Korea in recent years. Iran and Iraq are also expert state gsm jammer, among many others. The proliferation of RF jammers has been raising concerns worldwide and increasing the likelihood of serious maritime sector jamming incidents.