Completely isolating a mobile phone

[Man-wai Chang]

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Must I use aluminium foil? Why does Al make a difference?

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[JW]

On Tue, 16 Aug 2011 21:01:07 +0800 Man-wai Chang <toylet.toylet@gmail.com>
wrote in Message id: <j2dpmo$udc$1@dont-email.me>:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Must I use aluminium foil? Why does Al make a difference?

Try putting it into a microwave oven. Just don't turn on the oven.

 

[Man-wai Chang]

Must I use aluminium foil? Why does Al make a difference?
Try putting it into a microwave oven. Just don't turn on the oven.

That destroyed the phone, not stopping signals to reach it!

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[JW]

On Tue, 16 Aug 2011 22:18:37 +0800 Man-wai Chang <toylet.toylet@gmail.com>
wrote in Message id: <j2du83$uia$2@dont-email.me>:

Must I use aluminium foil? Why does Al make a difference?
Try putting it into a microwave oven. Just don't turn on the oven.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

That destroyed the phone, not stopping signals to reach it!

Please read what I wrote again for context.

 

[Jeff Liebermann]

On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
<toylet.toylet@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

<http://www.ramseytest.com>
<http://jretest.com>
<http://www.azimuthsystems.com/platforms-radioproof-402.htm>
<http://www.octoscope.com/English/Products/octoBox/RF_Isolation.html>
etc...

I could also do the necessary math to see how much isolation is
required, but since you didn't supply any details, I won't bother to
try.

Must I use aluminium foil? Why does Al make a difference?

<http://en.wikipedia.org/wiki/Faraday_cage>
<http://www.cvel.clemson.edu/emc/tutorials/Shielding02/Practical_Shielding.html>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
<toylet.toylet@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Did you put anything over the open end of the tin can?

Must I use aluminium foil? Why does Al make a difference?

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.

<http://berkeley.intel-research.net/arahimi/helmet/>
<http://zapatopi.net/afdb/>
<http://www.instructables.com/id/Aluminum-Foil-Hat/>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Robert Macy]

On Aug 16, 6:01 am, Man-wai Chang <toylet.toy...@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Must I use aluminium foil? Why does Al make a difference?

--
   @~@   You have the right to remain silent.
  / v \  Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
   ^ ^   (x86_64 Ubuntu 9.10)  Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

Dear Troller,

Wrap in two layers of 1 inch wide copper tape with conductive adhesive
from 3M Corp. Competely enclose.

 

[Ian Field]

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:908l479mk7jl7im259mubjltgl8vcd50g8@4ax.com...

On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
toylet.toylet@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Did you put anything over the open end of the tin can?

Must I use aluminium foil? Why does Al make a difference?

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.

Putting head in microwave oven is more permanent cure for mind control rays.

 

[TonyS]

On 16/08/2011 9:01 PM, Man-wai Chang wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Must I use aluminium foil? Why does Al make a difference?

Had to test it
In a tin can (tea can 2x2x3") fully closed: no reception
Overlapping lid only 2 mm open: reception
Microwave: no reception

Tony

 

[Jeff Liebermann]

On Wed, 17 Aug 2011 12:19:11 +0800, TonyS <nospam@mymail.com> wrote:

Microwave: no reception

Try a 2.4GHz cordless phone in the microwave oven. Punch the "find
handset" button on the base unit. The isolation of the oven is
usually insufficient and the phone will ring.

Let's run the numbers. A microwave oven belches about 1000 watts of
RF. The leakage spec is very roughly about 4 mw.
10 log (1000 / 4*10-3) = 54 dB isolation

In a strong signal area, the local cell site will probably produce
about -80dBm. (I cheated and just used the test mode on my cell phone
to get the number). The minimum sensitivity for the cell phone is
about -102dBm. In order to stop the phone from ringing, you need only
about 22dB of isolation. Since the microwave oven shielding is 32dB
better, which is 1400 times better, the microwave oven does quite well
at blocking cell phone signals.

However, the cordless phone is another story. The base transmitter
puts out about 10 mw into a really crappy 1/4 wave antenna, which will
product about -20dBm at the handset (with lots of assumptions that I
don't want to get into). The handset has a sensitivity of about
-104dBm, requiring an isolation of 84 dB to completely block the
signal. That's 30dB or 1000 times more than the 54 dB that the
microwave oven shielding can provide, so the cordless phone rings.

Note: All the numbers I supplied are bad guesses and are probably
wrong. However, since the isolation difference is 1000 times, it's
highly improbably that my numbers are in error by a factor of 1000. If
you have better numbers, that's fine, but the results will be the
same. The cordless phone will ring, and the cell phone will not.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Sylvia Else]

On 17/08/2011 4:46 AM, Ian Field wrote:

"Jeff Liebermann"<jeffl@cruzio.com> wrote in message
news:908l479mk7jl7im259mubjltgl8vcd50g8@4ax.com...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
toylet.toylet@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Did you put anything over the open end of the tin can?

Must I use aluminium foil? Why does Al make a difference?

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.


Putting head in microwave oven is more permanent cure for mind control rays.

He'll need to overcome the safety cut-out that the government requires
to be installed to prevent people escaping mind-control rays that way.

Sylvia.

 

[TonyS]

On 17/08/2011 12:50 PM, Jeff Liebermann wrote:
[snip]

However, the cordless phone is another story. The base transmitter
puts out about 10 mw into a really crappy 1/4 wave antenna, which will
product about -20dBm at the handset (with lots of assumptions that I
don't want to get into). The handset has a sensitivity of about
-104dBm, requiring an isolation of 84 dB to completely block the
signal. That's 30dB or 1000 times more than the 54 dB that the
microwave oven shielding can provide, so the cordless phone rings.

Sounds correct.
I have a 5.8GHz cordless.
It rings when in the microwave
Maybe someone can test a 2.4 one?

Note: All the numbers I supplied are bad guesses and are probably
wrong. However, since the isolation difference is 1000 times, it's
highly improbably that my numbers are in error by a factor of 1000. If
you have better numbers, that's fine, but the results will be the
same. The cordless phone will ring, and the cell phone will not.

 

[Man-wai Chang]

about -102dBm. In order to stop the phone from ringing, you need only
about 22dB of isolation. Since the microwave oven shielding is 32dB
better, which is 1400 times better, the microwave oven does quite well
at blocking cell phone signals.
....
don't want to get into). The handset has a sensitivity of about
-104dBm, requiring an isolation of 84 dB to completely block the
...

Thanks. Very detailed...


--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

Try putting it into a microwave oven. Just don't turn on the oven.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
That destroyed the phone, not stopping signals to reach it!

Please read what I wrote again for context.

Sorry for missing the last part and for my first impression about an
oven (always used to cook things).

OH well, I don't use microwave oven. It's too dangerous.

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

In a tin can (tea can 2x2x3") fully closed: no reception
Overlapping lid only 2 mm open: reception

I see...

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

Wrap in two layers of 1 inch wide copper tape with conductive adhesive
from 3M Corp. Competely enclose.

Do I need to ground the packing?

Looking up "copper tape" in Amazon, expensive stuff!

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.

Could I use the bags for potato chips? How many?

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Man-wai Chang]

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.
http://www.instructables.com/id/Aluminum-Foil-Hat/

I wonder whether an Al hat could stop psychic attacks? Psychic attacks
and/or magic are EM-waves as well?

--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Ian Field]

"Sylvia Else" <sylvia@not.here.invalid> wrote in message
news:9b12qpFjj0U1@mid.individual.net...

On 17/08/2011 4:46 AM, Ian Field wrote:
"Jeff Liebermann"<jeffl@cruzio.com> wrote in message
news:908l479mk7jl7im259mubjltgl8vcd50g8@4ax.com...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
toylet.toylet@gmail.com> wrote:

I threw it into a tin can then invert it. It still rang when I dialed
its number.

Did you put anything over the open end of the tin can?

Must I use aluminium foil? Why does Al make a difference?

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.


Putting head in microwave oven is more permanent cure for mind control
rays.


He'll need to overcome the safety cut-out that the government requires to
be installed to prevent people escaping mind-control rays that way.

Sylvia.

Some TV drama showed someone jamming plastic forks in the interlock catch
slots so it worked with the door open - failing that, anyone posting on a
sci.electronics group should have the knowhow to solder a mains lead
directly to the transformer tags.

 

[Jeff Liebermann]

On Wed, 17 Aug 2011 19:49:29 +0800, Man-wai Chang
<toylet.toylet@gmail.com> wrote:

Because aluminum is known to block the government mind control rays
that are forcing you to post such drivel. With an aluminum foil hat,
you will be safe from cell phone radiation and mind control rays.

Could I use the bags for potato chips?

Yes, but only if I get all the potato chips. I prefer the overpriced
non-greasy rice based salt and pepper kettle fried variety. Send to
address below.

How many?

One bag holds about 240g of chips.

Some of the companies I previously listed sell a fancy aluminum and
plastic bag, with a wire mesh view port, and built in foil gloves. It
is possible to tune a radio or pager in such a bag, but it's probably
awkward. Sorry, but I don't recall the company and didn't find
anything with Google.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558