Re: General Discussion on Jammers

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Re: General Discussion on Jammers

Post by bria » Thu Dec 31, 2015 2:35 pm

Sorry for the long post (as usual...).
The summary is this one "Don't do it, It will not do what you want, and you will just risk to go to jail without any gain".

Without doing any judgement, I want to give you some more information.

It's illegal in most country to use any jammer, on any frequency , on public space, and for multiples good reasons
For a cell phone jammer you've got theses effect around you
- you block not only "yours", but also other radio frequency.
- you disrupt emergency services (someone near you can't call 911/112/....
- You disrupt call of evertyone around you.
- You disrupt other sensitive electronic device which aren't well protected against 3W continuous emission (never hear a call coming from a speaker near your phone ? That the signal sended by your phone to the cell tower to acknowledge the call.. Cell phone doesn't send at 3W , and certainly not continuous).

The "common" jammer is a omnidirectionnal things , and to be sure to prevent any radiio wave hitting your equipement, it will create a "bubble" of much higher level radio wave in the same frequency. They will often "wooble" other a range , since saturating a large bandwidth ask energy (wooble they will continuously emit a "high" power emission with a narrow bandwidth, and the frequency of emission will vary with the time to cover all the range, with the constraint that the woobling is sufficiently fast to cover any communication, but sufficiently slow that the bandwidth of the jamming could effectly disrupt the communication).
(we don't speak about Electronic Warfare, or "hacker" level jammer with selective and directionnal beaming , false protocol (fuzzing). For example If it was only LTE frequency, they suffer a big weakness concerning the jamming ;)).

And after done all this, did you effectly avoid being tracked ?

Most of the jammer on your website cover ... unlicensed band (315-433) which is used for ... remote control garage door.
Some other will begin to attack 2G-3G signal (those "6-channel" at more than 200€ ...)

Only those above 500€ on your site begin to work on only one GPS band.

FYI : GPS frequency are on a total different frequency than call (~ 1.5Ghz, when gsm are in the 700-800 Mhz, 1800Mhz, and I don't remeber the third and fourth frequency, but above 2Ghz).
To be even more precise, GPS are on multiples frequency (L1-L5), where some are military encrypted (L5), and with jamming avoidance.
Gallileo is still in different frequency, same as GNSS (which adopt a different approche, while GPS and gallielo ad some coding multiplexingl (CDMA-style), and some Frequency multiplexing (each satellite have it own frequency).

So, did it prevent you from being tracked ? From 2005-device certainly. For new device, NO.

Third- bis
Actually, I could buy a mutli gps receiver for less than 50€, one that could get all these sattellite system. In addition it have a very low consumption. I could subsequent buy a microcontroller and a sd card and a big Li-ion battery for less than 50€. Let's just add for the good measure 50€ to have a beautifully sealed metal box , with a neodium magnet to resist any bump of the road. So for less than 200€ euros, I just defeat all you system, with a simple sd-card. Yes It ask for a physical access, but if you think you could had a tracking device, your car must lack any perimetric security at least once...

I wouldn't enter any more on electronic consideration, since it's not really the forum, but in reality, anyone with a little understanding to where find these sort of things could done it for less than $50. And a moderated skill hacker could even do a much more nasty things; a frequency agile from HF to SHF, jamming avoidance tracking system, for less than $800.

Before saying jammer are good or bad, or that we must or mustn't use , I want to define my opinion.

Jammer, as a gun, as a computer, as a car, are a tools. We must firstly define precisely what do we want, for what use. Then we could choose the technological tool the most adapted.

To prevent any phone call, don't use a jammer, just close it.
You want to avoid any tracking ? Fine, against which opponent ?
  • Against a man who just buyt this "beautiful new tracking device from china", yes a simple jammer will work, with GPS L1 jamming.
    (In computer security, this is the first level of an opponent, on three)
  • Against a true "hacker" (in the sens of someone who could modify something to use on a totally unexpected way) with knowledge on RF ? Get a true, military grade jammer, but better : assure a true perimetric security, and buy a signal detector instead, to see if your car try to communicate with the exterior.
    (second level , but if you are at this level, you can do some deception instead of jamming, which is way more fun).
  • Against a Governement level wanted to track you down/ SOF ?
    Lol, you're doomed (hint, if they feel something fishy, they will resort to the "mark1 sensor", and they have the man power to use it ).
    (third level).
All of this being said, jammer do have a true utility in any tactical situation.
- prevent radio communication of ennemies, while allowing yours (surprise, reco and sentinel elimination , ...)
- prevent remote detonation (IED on convy, even if they use also different detonation technique not depending on the radio).
- prevent any communication to/from the exterior of the crisis ... except land lines, and higly directionnal antenna (some satellite dishes with good rejection)
- prevent radio alarm sent on detection.

They also have drawback
- if any "heartbeat"/check are jammed, "bad guy" know that something is coming. And an ennemy which is prepared isn't a good thing.
- could easily be tracked to a point of origin, and could have retialation if the ennemy is good (goniometry). But this is the beginning of the EW :))
- You can never be absolutely sure it's "just work", since you've got no feedback from the ennemies. (and it could work for some, but not others, depending and the disance, their radio, whom they tried to connect, the weather etc...)

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Re: General Discussion

Post by tacticalguy » Mon Jan 04, 2016 6:34 am

Bria, that was spam. I deleted it. Thank you for your conscientious attempt to chasten the spammer.
If you have `cleared' all the rooms and met no resistance, you and your entry team have probably kicked in the door of the wrong house.
(Murphy's Cop Laws)

The greatest enemy of a good plan is the dream of a perfect plan. (Von Clausewitz)

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