RF-Blocking Wallpaper

spitefulcrow writes "Silicon.com is reporting on a new application for RF-absorbing materials: Wallpaper that blocks Wi-Fi. BAE, the British defense contractor, has announced that the same material used to foil radar by stealth bombers can be used to selectively block certain frequencies and prevent wireless networking signals from entering or exiting a building. Is this the next take on lining the walls with lead?"

Comments

I'm really busy

[isoprophlex]

I will be wonderful when the adhear this technology in movie cinemas so that the wankers sitting behind me who answer there phones during the films, can't take their "important calls".

Re:I'm really busy

[nacturation]

What if a doctor were to go watch a movie and one of his patients started dying and he needed to be contacted? What if a loved one were in an accident and people were trying to get ahold of you so you could possibly see them before they died?

There are many scenarios where having cell reception is important.

Man, what *did* people do before cell phones? Give out the public number to the theatre/opera/amusement park/restaurant/stadium's land line and have an employee come and get them if they got a call?

Actually, an interesting note is that some classy restaurants offer this as a service. They ask you to forward your cell phone to a special number, let them know your name and where you're sitting, and the restaurant staff picks up the call and comes and gets you. "Excuse me, Mr. Smith, but you have a call. This way please..."

Why Not Just Encrypt?

[afriguru]

UK defence contractor BAE Systems has developed a stealth wallpaper to beat electronic eavesdropping on company Wi-Fi and wired LANs.

Instead of qoing through the hassle of covering a building with this wallpaper, why can't system admins just get into the habit of implementing encryption all the way (particularly for Wi-Fi networks?)

Interesting

[hot_Karls_bad_cavern]

For sometime i've wanted to have my main workstation off the network, grid and inside a faraday cage. But think about how ridiculous that would be/look? The other machines in the house would be okay to leave alone, but i'd want at least one that i knew was safe (data transfers would be on extreme need only, i.e. data sets into and encrypted messeges written inside).

But i'm getting away from my original point: this is sweetness. No, it's not exactly what i'm looking for, but it's a stop in the correct direction. Think you've never had a neighbor whom owns a 900MHz scanner? Anyway, i think this is great. You and i both know that information, its protection, secure dissemenation, and reliability of said information are the weapons of the upcoming century. You need to have your data safe whether you think so or not, so the more things like this the better.

Shielding is Hard

[Detritus]

Assuming that you cover the walls with this stuff, you still have to worry about the floor, ceiling, windows, doors, ventilation ducts, plumbing and electrical wiring, plus any holes or gaps in the shielding. Then there is telephone, LAN and video wiring to worry about.

Yes, hospitals too.

[teidou]

Most people don't understand why hospitals would use this: every hospital I have worked in would be interested.

Cell phones, even by being on can affect drug infusion pumps: it is not good to have the infusion rate spontaneously jump from 1 mL/min to 100mL/min. What's worse is that some people don't know the difference between "standby" and "off" - they think just not using it will turn off the transceiver. (Yeah, yeah, Snopes says it's not a big problem. They're FOS on this one: it really does happen).

Some visitors argue it is a problem with the medical equipment and they should get to keep their phone on: 1) possibly a valid point, but the fact is that patient health is threatened by the phone, and 2) the historic FCC position is that RF shall not interfere with other equipment. (Incidenally, new medical equipment is better shielded (hinted at on the FDA website).

Finally, to the genius who wants to point out that many hospitals are using wireless for notebook computing and wireless monitoring: 1) those in use are on different frequencies than cell phones, and 2) they are very carefully tested before implementation, (Also, I'm not sure on this point, but I believe they are probably less powerful than cell phones; this is why repeaters are in every hallway rather than just one on the roof. If the wallpaper is just on the exterior of the building, I doubt it would not interfere with current use).

Teidou

Re:Yes, hospitals too.

[Myself]

While you're right that it's the transmitter's responsibility not to cause interference, I still think it's dangerously irresponsible to keep old machines in service that've proven themselves unreliable in the face of common interference.

You make an excellent point that the WLANs used in hospitals are very low power. Yes, they put APs every few yards down the hallways, so that the portable devices never have to step up their transmit power to reach one.

The solution to the cell phone problem in hospitals is to put base station equipment IN the hospital and run Radiax down the hallways. Alternately, just put cell sites as close to the building as possible. When the phones can reach a tower easily, they'll limit their output power accordingly.

This is also the counterintuitive solution to the weenies who protest when a cellphone company wants to put a tower near the high school. (This frequently happens when an athletic field is getting new lights.) Compare a cordless phone to a moonbounce transmission, which requires more power?

The first mobile phones weren't cellular, there was a single base station in the center of town. The powers used were on the order of 50 watts, so it's a good thing the vehicle-mounted antenna was several feet from the handset. When cellular was developed, it meant you were always within a mile or two of a tower, so the power levels decreased drastically. Phones reduce their output power in response to requests from the tower, because it's easier for the tower to "hear" the faint phones if the near phones aren't screaming.

Shielding the place into an RF hole is counterproductive. In the event that someone forgets to turn their phone off, it'll sit there chirping out its maximum transmit power every once in a while, searching for a tower it can't find. Worse yet, it'll maintain contact with a tower it can just barely hear, only if it really blasts out the RF. This helps nobody.

This scream "health issue"

[shpoffo]

Does this sound to anyone else as causing similar problems as reported by a study from the UK (reported here on /.) about cel phone usage in trains raising the ambient radiation levels about those deemed safe by regulatory committees? When the waves are 'blocked' I get the sense that they're reflected back into the space. Probalby makes for a stronger signal, but you'll also get radiation build-up, and perhaps focusing effects - where you'll get small spaces where there will be a literal 'hot spot.' Everyone could go and set their food on the left corner of the third filing cabinet from the end of Dave's cubicle for a few minutes to heat it up before lunch......

yuck

.
-shpoffo

My parents were doing this when I was a kid

[macemoneta]

My mom always loved the foil/felt (flock) wallpapers in our dining room, when I was growing up (about 40 years ago). The foil was always grounded, because it went under the (metal) outlet and switch covers, which in turn grounded to the (metal) box. I know the foil was conductive, because we once had a two-wire appliance short to it's metal case (before the days of 'double insulated' design), and I got a shock touching the wall and appliance.

Maybe companies selling this kind of wallpaper should rebrand it as inexpensive high-tech (but low cost) Faraday shielding. And maybe the defense agency could save a few billion dollars by using an off-the-shelf solution. Nah.

I know a man who had this in the Eighties...

[qtp]

The computer room (floor, walls, and ceiling) was lined with akluminized wallpaper, the window had an aluminum screen. His own home-built faraday cage.

As he did not have wi-fi, I beleive that he was more concerned with preventing eavesdropping of his CRTs rf feild. There were other CS guys (from the uni) who did the same thing.

As he my first real programming teacher, I always assumed that the tech to "tempest" a CRT was available then. Tapping WiFi is undoubtably a magnitude simpler.