Cell Phone Blocking

[Azndude51]

I was at my local county library today and they had a sign up saying that they are now blocking cell phone signals in the building, with the exception of one area. IIRC, cell phone blocking is illegal, how can they do this?

 

[Heisenberg]

Active jamming is illegal. Passive blocking is legal IIRC, but I'm not 100% sure on that.

Edit: A quick google search says passive blocking is legal.

 

[DnetMHZ]

From the FCC

Blocking & Jamming

The operation of transmitters designed to jam or block wireless communications is a violation of the Communications Act of 1934, as amended ("Act"). See 47 U.S.C. Sections 301, 302a, 333. The Act prohibits any person from willfully or maliciously interfering with the radio communications of any station licensed or authorized under the Act or operated by the U.S. government. 47 U.S.C. Section 333. The manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in violation of these provisions may be subject to the penalties set out in 47 U.S.C. Sections 501-510. Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the U.S. government.

as mentioned above passive blocking is still legal.

 

[Azndude51]

What's the diff between passive and active jamming?

 

[Jzero]

Originally posted by: Azndude51
What's the diff between passive and active jamming?

Active jamming is generating some sort of interference radiation.

Passive jamming is building thick walls, faraday cages, TEMPEST-type stuff.

 

[MrBond]

Originally posted by: Jzero

Originally posted by: Azndude51
What's the diff between passive and active jamming?

Active jamming is generating some sort of interference radiation.

Passive jamming is building thick walls, faraday cages, TEMPEST-type stuff.

I saw yesterday that there's actually a new paint out now with nanotubes mixed in that blocks cellphone signals. Just paint the room and boom, no signal.

 

[giantpinkbunnyhead]

Originally posted by: Azndude51
What's the diff between passive and active jamming?

An active event is one in which a process is used to make the event happen.
A passive one is when the event happens without a process.

So active jamming means a process of some sort is being used (such as generating interfering signals) to block the cell signals; while a passive one lacks any such process and it just "happens" due to prevailing circumstances. Such as thick walls, nanopaint, etc.

 

[Azndude51]

how would the library go about blocking the signals without active blocking? I used to get a strong signal in the building, then one day, there's no signal and the sign is up. I doubt they used the nanopaint or anything like that.

 

[Baked]

If people could be more considerate of others, such as setting their cell phone to vibrate and talk outside when they have a call, the library wouldn't have to result to such measures. But as is, a lot of cell phone users are self center a holes.