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RF blocking stickers for cell-phones

by xykotik
Tags: blocking, cellphones, stickers
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xykotik
#1
Jun21-09, 01:08 AM
P: 10
I still see these things around! It drives me nuts that I even have to explain it to people, but it's so hard to cover my judgemental feelings toward the lunacy (and outright fraud) with a kind semi-technical explanation that I think they just shut me out.

I was hoping to find a nice website with maybe some illustrations. Has anyone seen such a thing? I hope I didn't overlook it in this forum. I suppose I could get motivated and do it myself, but it is more productive to not duplicate effort, and there has to be something out there already.

(oh yeah, they usually come with the "range-extender" sticker to put on your battery. AHHH!)
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Anticitizen
#2
Jun25-09, 06:51 PM
P: 128
I work for a mobile phone company. I'm now in sales but began as a technician, repairing faulty/damaged handsets. You wouldn't believe how many of those damn stickers I saw on people's phones.

Whenever a customer asks me if they work, I respond by reminding them that millions of dollars of research by scientists go into design and testing of the handsets, and if a little foil sticker really aided their operation, they'd come pre-installed from the factory :)
DaveC426913
#3
Jun25-09, 07:45 PM
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Perhaps you could start with a description of exactly what it is you're talking about for those of us who apparently live under a rock.

What stickers? What do they do?

negitron
#4
Jun25-09, 07:58 PM
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RF blocking stickers for cell-phones

Quote Quote by DaveC426913 View Post
What stickers? What do they do?
These. They do exactly what you expect them to: separate retards from their money.
Moonbear
#5
Jun25-09, 07:59 PM
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I think it's getting crowded under this rock, Dave. I've never heard of these stickers either.
Moonbear
#6
Jun25-09, 08:04 PM
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Quote Quote by negitron View Post
These. They do exactly what you expect them to: separate retards from their money.
LOL! Wow, people pay $20 for a sticker? (Yes, I had to click the "add to cart" button to find out how much they cost...always a sure sign of a scam.)
skeptic2
#7
Jun25-09, 08:51 PM
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I don't use one on my phone but I would love to find out how much it affects the field strength. If someone has a sticker and access to a field strength meter or even a spectrum analyzer, would you make some comparative measurements and post the results here? My guess is that it not only acts somewhat as a shield but also changes the impedance of the antenna and causes some of the signal to be reflected back to the phone.
Moonbear
#8
Jun25-09, 09:40 PM
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Quote Quote by skeptic2 View Post
I don't use one on my phone but I would love to find out how much it affects the field strength. If someone has a sticker and access to a field strength meter or even a spectrum analyzer, would you make some comparative measurements and post the results here? My guess is that it not only acts somewhat as a shield but also changes the impedance of the antenna and causes some of the signal to be reflected back to the phone.
I don't think it'll do anything. If you check out the site negitron linked to, they are just little perforated stickers that fit over the earpiece part, nowhere near the antenna.
DaveC426913
#9
Jun25-09, 09:42 PM
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Just to be Devil's Advocate, what is your evidence that they do not work?

I'm not doubting that they don't; I'm sure they don't, but can you show it? We can't accuse others of succumbing to myth or to common-sense or gullibility if we don't have evidence-based facts behind us.

[ EDIT ] OK, first point I grant: radiation does not come out of the speaker holes.
DaveC426913
#10
Jun25-09, 09:47 PM
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Radiation-blocking stickers aside, there's something I've never understood about this whole 'don't hang it on your belt' thing.

A phone that is receiving a signal is not an EM radiation source. It is simply processing the ambient radio signals in the atmo.

A phone that is sending a signal is an EM radiation source. But it is not on your hip; it's on your face.

So, before anything else is said and done, how does a phone on your hip expose you to dangerous EM radiation?
fleem
#11
Jun25-09, 09:51 PM
P: 461
Quote Quote by DaveC426913 View Post

So, before anything else is said and done, how does a phone on your hip expose you to dangerous EM radiation?
Phones periodically contact the local tower to let it know its there.

As for the sticker, they do nothing. Its 100% scam. the lion's share of EM fields is in the transmission, itself. So if the sticker DID block anything notable, it would also reduce the range of the phone.
negitron
#12
Jun25-09, 09:52 PM
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Quote Quote by DaveC426913 View Post
So, before anything else is said and done, how does a phone on your hip expose you to dangerous EM radiation?
A phone that's turned on will periodically send out a locational signal so the network knows where the phone is in order to route calls most efficiently. Also, when the phone rings for an incoming call, it sends out an acknowledgment signal so the network knows the phone is on and is receiving the signal.
Moonbear
#13
Jun25-09, 10:35 PM
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I assumed the don't hang it on your belt thing was since people started using those bluetooth things, so your phone is still on your belt while in use. Though, I'd think it would be better on your belt than in your pocket. Guard your gonads guys!

I was expecting this to be something that goes over the antenna, or wraps around the whole phone like a cover or something. Something that is only big enough to cover the speaker holes, and still has holes in it leaves me wondering how people fall for it. Maybe they just like the gold or silver stickers and think of it as "bling" for their phones, not so much thinking it works?
DaveC426913
#14
Jun26-09, 07:52 AM
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Quote Quote by Moonbear View Post
Something that is only big enough to cover the speaker holes, and still has holes in it leaves me wondering how people fall for it.
Perhaps people have become comfortable with their microwaves, which need only a mesh to block radiation.
Anticitizen
#15
Jun26-09, 02:33 PM
P: 128
I assumed the OP was talking about these, which were much more popular to see on peoples' phones in the repair shop than the 'radiation blockers':



The claim is that they will boost your signal.
Anticitizen
#16
Jun26-09, 02:39 PM
P: 128
Here is a randomized, double-blind, placebo-controlled test of the 'booster' sticker:

http://www.andybrain.com/extras/cell...w-and-test.htm
Anticitizen
#17
Jun26-09, 02:45 PM
P: 128
Quote Quote by DaveC426913 View Post
Radiation-blocking stickers aside, there's something I've never understood about this whole 'don't hang it on your belt' thing.

A phone that is receiving a signal is not an EM radiation source. It is simply processing the ambient radio signals in the atmo.

A phone that is sending a signal is an EM radiation source. But it is not on your hip; it's on your face.

So, before anything else is said and done, how does a phone on your hip expose you to dangerous EM radiation?
Actually, mobile phones are not passive. They 'ping' the network on a schedule called a 'slot cycle' which is usually every 1-5 seconds or so to check for incoming calls, messages, etc. On some phones, you can access a hidden programming menu that will allow you to manually change the slot cycle index - you can raise it so only pings, say, every seven seconds which will improve your battery life, but if a call comes in, your phone might not start ringing for up to seven seconds. The phone doesn't know it has an incoming call 'till it checks.

Pagers are passive, though.
skeptic2
#18
Jun26-09, 03:52 PM
P: 1,814
Those stickers may also cause shorter battery life. If they reduce both the radiated and received signal strength then the base station will tell it to turn up its power to compensate.


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