How to detect cell phones?

Question

Information Security

Good afternoon! Faced with the problem it is necessary to detect cell phones of all ranges and OPPS at an enterprise where they are prohibited. It is necessary to implement a certain system of sensors so that you can detect in which room the phone is working, using jammers is not an option. Has anyone faced this issue? Are there any such sensors?

Answer 1

You can buy a femtocell and see in the admin panel which devices are connected to it. Various connection options will be visible, but you need to check.

Answer 2

Yes, I did. But honestly, forget it. Once you know the approximate order of the price - you will understand. Roughly speaking - you need to monitor radio frequencies in the right ranges. Monitors should be:
1. not very sensitive - so as not to hear the signal behind the wall. This is just solvable and simple
2. they need at least the number of rooms
3. they should be able to somehow report the status, and not just pull the arrow and flash the light
4. well, you need monitoring
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Most likely - it’s unbearable for you . Alas, often it is necessary to prove to the authorities.
You can also do this:
a. scatter frequency indicators around the premises. I'm not strong in electronics, so maybe they will be needed in terms of the number of ranges.
b. through arduino or else how to pile a monitor of their activity
...
n. profit
In short, it is difficult, very difficult. Almost always the game is not worth the candle.

Answer 3

at the enterprise where they are prohibited

In my opinion (I am not a security guard), it is more logical to once search the entire territory (with the involvement of specialized specialists) and introduce an inspection (frame metal detector and manual) at the checkpoint.

it is necessary to detect cell phones, all bands and FPSO

Regarding the detection of radiation sources, I observed the use by specialized specialists of approximately the same product from Rohde & Schwarz (they were looking for an unadvertised source of radio emission). As far as I remember, the cost is about tens of thousands of dollars, in addition, a specialist with the appropriate qualifications is needed.
If suddenly the phone is turned off, and you really need to find it, then a non-linear locator will probably help here, but this, in my opinion, is an even more specific product.
Exemplary measures (of those that I personally observed) to ensure "silence on the air" I described to you.

Are there any such sensors?

As for the detection of radiation sources with an accuracy of the room of the building by a system of [factory-made, not home-made] stationary sensors, I can’t tell. As far as I know, most often they first analyze the air received by an omnidirectional antenna (roughly speaking, they look at the "waterfall"), then, when the desired signals are detected, they carry out a narrower analysis in terms of azimuth / position (directional antennas, portable scanner / spectrum, other "fox hunting").
In short, it's a little unclear what the specific end goal is and what the resources allocated to achieve it are.

The specific goal is very simple, like a colony.

For example, or a colony? Specificity can bring a lot of nuances.

Silencers are not an option, as there may be other houses nearby that are affected by jammers,

What does "may be" mean? If there is a given colony, then there are residential buildings next to it or not. Or are you developing a common project?

plus doctors against.

What does "doctors against" mean? What indicators of the EM field do not suit them? What standards are being violated? Further, no one offers you to customize the electronic warfare complex and fry the ether. Now, as far as I know, there are low-power intelligent means of suppressing mobile phones (roughly speaking, there are “sticks” on the screen, but it is impossible to make a call). I won’t tell you a factory product, I saw products of small-scale semi-handicraft production.
You did not indicate what resources you have at your disposal, although I already guessed that buying an expensive prof. equipment is incredible.
By the way, there is a story that is popular in narrow circles, how once a similar task in a colony remote (this is important) from the base station was solved by a high fence made of metal mesh.

Answer 4

In theory, such sensors belong to special equipment. You can, of course, come up with something on your knee, but you should look for a ready-made IMHO in that direction.

Answer 5

How to detect cell phones?

Obviously, with the help of special equipment.
Obviously, special services and security personnel.
It's easy to google for keywords www.bnti.ru/index.asp?tbl=04.01.01.10.
In fact, there are even more of them.

Answer 6

This technique is prohibited in free circulation.
At the time of receiving a call, exchanging gprs-data from a mobile, interference is created on the radio equipment. It makes sense to analyze this topic and use the radio as a search device. Also ring the worker's phone, and even if the selection and signal are turned off, then at this moment the radio should make noise.
If the enterprise is not large, then as an option, you can think about purchasing a signal jammer that is installed in sensitive rooms.
The second option, if the phone is based on Android OS, etc., that is, there are various kinds of software with which you can turn on the serena on the phone in case it is lost, take pictures, etc. I think we can try to apply similar software here. But first you need to work directly with the phone. For example "Prey" for Android.
Didn't think of anything else.

Answer 7

Some strange question. If this is a colony / prison and the task is officially - then why is it being solved on the knee, and not through the OPSOS ????
A mobile phone from a given square has connected, and is not whitelisted - turn it off and block it by the phone number on the SIM card and IMEI forever.
In Belarus, say, lost/stolen phones block IMEI. I called from my phone with a stolen SIM card (I was walking down the street, and she was lying on the pavement) - the same story. Go to the police and prove that you are not a camel.