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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

On Tue, 16 Aug 2011 21:01:07 +0800 Man-wai Chang
wrote in Message id: :


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.

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

On Tue, 16 Aug 2011 22:18:37 +0800 Man-wai Chang
wrote in Message id: :

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.

On Aug 16, 6:01Â*am, 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?

--
Â* Â*@~@ Â* You have the right to remain silent.
Â* / v \ Â*Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
Â* Â*^ ^ Â* (x86_64 Ubuntu 9.10) Â*Linux 2.6.39.3
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):http://www.swd.gov.hk/tc/index/site_...sub_addressesa

Dear Troller,

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

On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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.

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

On Wed, 17 Aug 2011 12:19:11 +0800, TonyS 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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 17/08/2011 4:46 AM, Ian Field wrote:
"Jeff wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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.

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.

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

"Sylvia Else" wrote in message
...
On 17/08/2011 4:46 AM, Ian Field wrote:
"Jeff wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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.

On Wed, 17 Aug 2011 19:49:29 +0800, Man-wai Chang
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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:

On Wed, 17 Aug 2011 19:49:29 +0800, Man-wai Chang
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.


Ramsey used to sell that equipment.


--
Subject: Spelling Lesson

The last four letters in American.........I Can
The last four letters in Republican.......I Can
The last four letters in Democrats.........Rats

End of lesson. Test to follow in November, 2012

Remember, November is to be set aside as rodent extermination month.

On 17/08/2011 11:01 PM, Ian Field wrote:
"Sylvia wrote in message
...
On 17/08/2011 4:46 AM, Ian Field wrote:
"Jeff wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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

Sheesh - talk about irresponsible broadcasting.

Sylvia.

On 17/08/2011 2:19 PM, TonyS wrote:
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

How did you check that you can hear the phone ring inside the completely
closed can?

Sylvia.

On Wed, 17 Aug 2011 19:08:05 -0400, "Michael A. Terrell"
wrote:

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.

Ramsey used to sell that equipment.

Yep. They did, but I don't see it on their web pile:
http://www.ramseytest.com
Probably discontinued due to the low demand for RF proofing potato
chips.

I actually used one of those bags for tuning pagers in about 1972. It
sorta worked, but wasn't any fun. Try tuning something small while
wearing welding gloves for a fair simulation. We later switched a
home made RF shielded box, with aluminum on mylar foil gloves built
in. After I left, they bought an aluminum semi-truck trailer, fitted
the doors with copper fingers, installed HVAC, filtered the entry
wires, and build a somewhat mobile screen room.

RF shielded "tent"
http://www.shieldextrading.net/tents.html
Sigh... I was hoping for a pyramid power tent.

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

What you need is a bucket of water.

J

On 18/08/2011 9:14 AM, Sylvia Else wrote:
On 17/08/2011 2:19 PM, TonyS wrote:
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

How did you check that you can hear the phone ring inside the completely
closed can?

Sylvia.

I thought it should be obvious. The can rattles like hell when the
vibrator goes off

Tony

On 18/08/2011 3:29 PM, TonyS wrote:
On 18/08/2011 9:14 AM, Sylvia Else wrote:
On 17/08/2011 2:19 PM, TonyS wrote:
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

How did you check that you can hear the phone ring inside the completely
closed can?

Sylvia.

I thought it should be obvious. The can rattles like hell when the
vibrator goes off

Tony


Hmm... OK, I'll give you that one. I don't use mobile phones much -
perhaps it shows.

Sylvia.

On 18/08/2011 1:33 PM, Sylvia Else wrote:
On 18/08/2011 3:29 PM, TonyS wrote:
On 18/08/2011 9:14 AM, Sylvia Else wrote:
On 17/08/2011 2:19 PM, TonyS wrote:
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

How did you check that you can hear the phone ring inside the completely
closed can?

Sylvia.

I thought it should be obvious. The can rattles like hell when the
vibrator goes off

Tony


Hmm... OK, I'll give you that one. I don't use mobile phones much -
perhaps it shows.

Sylvia.

Don't worry Sylvia, I still consider yours one of the best brains on
usenet

Tony

On 18/08/11 1:16 PM, Jeff Urban wrote:
What you need is a bucket of water.

I wanna shield it from RF, not destroying 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
�借貸! ��騙! ��交! �打交! �打劫! �自殺! 請考慮綜� (CSSA):
http://www.swd.gov.hk/tc/index/site_...sub_addressesa

Jeff Liebermann wrote:

On Wed, 17 Aug 2011 19:08:05 -0400, "Michael A. Terrell"
wrote:

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.

Ramsey used to sell that equipment.

Yep. They did, but I don't see it on their web pile:
http://www.ramseytest.com
Probably discontinued due to the low demand for RF proofing potato
chips.



I think they dropped the line about five years ago, but some of it
shows up on Ebay.


I actually used one of those bags for tuning pagers in about 1972. It
sorta worked, but wasn't any fun. Try tuning something small while
wearing welding gloves for a fair simulation. We later switched a
home made RF shielded box, with aluminum on mylar foil gloves built
in. After I left, they bought an aluminum semi-truck trailer, fitted
the doors with copper fingers, installed HVAC, filtered the entry
wires, and build a somewhat mobile screen room.


I've worked in real screened rooms, without air conditioning at the
old Cincinatti Electronics plant (Glenndale-Milford Road)in the mid
'70s.


--
Subject: Spelling Lesson

The last four letters in American.........I Can
The last four letters in Republican.......I Can
The last four letters in Democrats.........Rats

End of lesson. Test to follow in November, 2012

Remember, November is to be set aside as rodent extermination month.

On Thu, 18 Aug 2011 09:57:51 -0400, "Michael A. Terrell"
wrote:

I've worked in real screened rooms, without air conditioning at the
old Cincinatti Electronics plant (Glenndale-Milford Road)in the mid
'70s.

Ditto. At Granger Assoc, we needed to build a temporary screen room
in order to accurately tune and measure some radios. Instead of
buying a proper Lindgren screen room, we built our own with lumber and
brass screening material, which was much cheaper and easier to move if
necessary. No finger stock on the door, but some foam behind the
brass screening provided adequate spring action. The isolation wasn't
perfect, but it worked. The screening gave the room access to the
building air conditioner, so there was no overheating. Unfortunately,
it became my office for a short while, resulting some rather bad
jokes.

At Intech Inc, we had a shield transmitter burnin room. At the time,
copper was relatively cheap, so the room was clad in copper sheet
metal with no screening. I would hate to think what that would cost
today. Heat buildup was substantial, so we used the thermal
conductivity of the copper to move away much of the heat. The door
leaked somewhat, so we contrived an arrangement that made it look (and
weigh) like a bank vault door. That worked.

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

On Thu, 18 Aug 2011 19:45:11 +0800, Man-wai Chang
wrote:

On 18/08/11 1:16 PM, Jeff Urban wrote:
What you need is a bucket of water.

I wanna shield it from RF, not destroying it.

Destroy the phone or the RF? If the RF, you can neutralize the
deterimental effects of RF using Orgonite stones.
http://www.orgone.net/05_orgone_energy_and_dor.html
http://cellularpcs.com/2011/04/03/orgonite-the-cure-for-cell-towers/
When placed near a source of RF, they are known to aborb the harmful
radiation, leaving only natural radio waves, which can then safely and
easily be shielded with tin foil or absorbed in a carbon foam sponge.

Also see "gifting" with Orgonite:
http://www.youtube.com/user/ctbusters
www.youtube.com/watch?v=xZMlbRBRuSo

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

Jeff Liebermann wrote:

On Thu, 18 Aug 2011 09:57:51 -0400, "Michael A. Terrell"
wrote:

I've worked in real screened rooms, without air conditioning at the
old Cincinatti Electronics plant (Glenndale-Milford Road)in the mid
'70s.

Ditto. At Granger Assoc, we needed to build a temporary screen room
in order to accurately tune and measure some radios.


These were in what had been a Crosley machine shop during W.W.-II,
and the test equipment ran so hot that it was over 100F some nights. I
worked second shift, so it was already geting hot from the day shift. I
was doing QA work on the PRC-77 manpack radio. I prefered running the
SATE, in it's aluminum computer booth, with the AC set at 68 F. The
SATE system was controlled by a four bit Data General mini-computer.


Instead of
buying a proper Lindgren screen room, we built our own with lumber and
brass screening material, which was much cheaper and easier to move if
necessary. No finger stock on the door, but some foam behind the
brass screening provided adequate spring action. The isolation wasn't
perfect, but it worked.


I had enough new brass screening to build a proper shieleded room but
it was lost in a rental warehouse when I got sick, 10 years ago. I am
thinking about using two layers of foil back foam insulation to build
one for my home shop. I had a box of phosper bronze finger stock that
should be enough to seal the door, if it survived the last huricane.


The screening gave the room access to the
building air conditioner, so there was no overheating. Unfortunately,
it became my office for a short while, resulting some rather bad
jokes.


At least you didn't have to wear your foil beanie at work. ;-)


At Intech Inc, we had a shield transmitter burnin room. At the time,
copper was relatively cheap, so the room was clad in copper sheet
metal with no screening. I would hate to think what that would cost
today. Heat buildup was substantial, so we used the thermal
conductivity of the copper to move away much of the heat. The door
leaked somewhat, so we contrived an arrangement that made it look (and
weigh) like a bank vault door. That worked.

Ian Field wrote:


"Jeff Liebermann" wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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.

You can't just stick your head in and microwave it. There's a door
interlock to deal with.

The head must be severed to put it in with the door closed. Then, the whole
microwaving thing becomes moot.

--
Paul Hovnanian
------------------------------------------------------------------
Porsche 928: 0 to c in 2.125 years, 2.435 light-years per mile^3 of gas

"Paul Hovnanian P.E." wrote in message
diainc...
Ian Field wrote:


"Jeff Liebermann" wrote in message
...
On Tue, 16 Aug 2011 21:01:07 +0800, Man-wai Chang
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.

You can't just stick your head in and microwave it. There's a door
interlock to deal with.

Undo half dozen screws - lift off cover - solder mains lead to transformer
tags - insert head and hit wall socket switch.

Or just jam a couple of plastic forks in the door catch slots.