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Hi! I have a client school that has asked if it is possible to set up a system such that the entire school (inside) is blocked from cell phone use. They already post signs CELL PHONES NOT PERMITTED INSIDE SCHOOL FACILITIES however both the students and the staff don't comply! So the board has requested a '..cell phone cloak...' to block all cell useage inside of the building.

In our area we see CDMA (both 3G and 4GLTE), as well as GSM (the gamut of ATT, SPRINT, VERIZON & VIRGIN). Obviously we cannot tell what phones are used by which people. They simply want ALL cell services blocked.

The school building is 4 floors - with corridors around the floors (ideal to create a perimeter block-shield for the rest of the floor!). Each floor about 200' long x 60' wide.

Our concern is two-fold: First, we cannot block WIFI as many school services use wifi bands as data transport (smart boards, security cameras, etc.). Second, as the building is ATTACHED to other buildings we want to minimize bleed into neighbors. Finally, we want to make sure that when power is lost - and then restored - the units 'remember' their state; i.e. either on or off, and recover to the same state.

Looking at your various units available, very few detail the frequency range that is blocked. I.e. they just say 3G... As 3G and wifi are close... we need to make sure that we don't block wifi - so we're fearful of say the MGT40 (to 2500!!),. It seems that the RCJ40-D might be the right unit to utilize?

We are thinking of 2-3 units per floor, overlapped and drawn in towards the centers so as to minimize neighbor impact - and all units on power switches that turn the units on at start of school day and then turn off at end of school day. 10 hour days - 5 days a week.

Can you suggest/comment on our thoughts?

asked Feb 03 '12 at 05:31

ChadManson's gravatar image


Hi Chad!

As I can see from what you have written, the problem is especially acute in your case. You need to cover whole school with blocking signal that will jam 3G, 4G and all GSM and CDMA frequencies. Your choice of the unit to utilize is right because the adjustable five bands desktop jammer RCJ40-D suites your case in the best way. First of all, its frequency bands will be tuned to work with frequencies you need - GSM850 (CDMA800), GSM900, GSM1800 and GSM1900 (DCS, PHS), and 3G. Just don't forget to choose them during your ordering process. The quantity of 2-3 units per floor should be enough, and if the jamming signal will go beyond the school area, you can use the control knobs to make its output slightly lower for jamming signal to stay inside the school area.

As for 4G, you need to use another device - XLG15 4G LoJack jammer. It is not desktop but portable one, so its jamming radius is smaller thus you need 4-6 units to cover each floor. As for WiFi interference, you may not worry about it. If you read the first part of the article about frequencies we jam, you'll see that GSM band is far from WiFi, and in second part you'll see that 3G is also far from dangerous range. The only threat for your WiFi network is the 4G signal jammers because its frequencies are really close to the WiFi frequencies. I can advice you to take one XLG15 and test if it will interfere with the WiFi network of your school. If so then there would be two options: leave 4G band for students and staff to use or accept the fact that your smart boards and security cameras will work worse than they should.

You know, the problem of students using mobile phones and other personal gadgets in schools is not new but different schools deal with it in a different way. You have decided to block the whole school from mobile devices and maybe it is right thing to do. In any way, I hope my answer will help you to manage this matter successfully! :)

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answered Feb 03 '12 at 06:04

JammerStore's gravatar image

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question asked: Feb 03 '12 at 05:31

question was seen: 15,283 times

last updated: Feb 03 '12 at 06:04

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