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Cell Why
Microwave Ovens Can Have See Through Windows
Lifebluetube Headset
Cell Phone Towers Health Effects
Cell Phone Sensitivity
EM Field Meter
Have you ever wondered why a microwave oven can have a
see-through window? “Microwaves” are radiation after all. We
all know about tempered glass as commonly used in convention
ovens, but microwave ovens also have a perforated metal mesh
screen on the inside of the glass. How does this help?
How is this perforated screen on microwave ovens effective
against microwave radiation?
Beginning with the basics; microwaves are in fact,
radiation. High frequency radio waves to be exact, but
radiation all the same. But so is any form of heat, light,
sound, etc. They too are radiation. Throwing a baseball is
in fact, a form of ‘radiation’ in that the ball is
‘radiating away from’ where it started. In short, any linear
path movement is radiation and the trajectories of a
baseball or a golf ball etc. are in the strictest sense,
radiation.
In electromagnetism, there are two concerns; mutagenic
(ionizing) and non-mutagenic (non-ionizing) radiation. The
non-ionizing type are what microwaves are. In fact, on the
EM scale microwaves fall below ordinary heat-lamps in their
radiation output. Microwave radiation is a form of high
frequency radio wave but still of the non-ionizing type. No
charged ions are produced when the microwave passes through
matter, but it has just enough energy to produce molecular
excitation which is turn creates heat. This is how a
microwave ‘cooks’ food. Even if a microwave oven had a bad
seal or other ‘hole’ in it, during normal operation it would
not be lethal. Placing your face or fingers near the opening
during use would give you a burn rather quickly however.
People with pacemakers should stay well back from a
microwave oven in use as microwave radiation is after all,
radio waves which could affect the ‘timing’ and thus, the
proper functioning of the heart implant device.
The Faraday Cage
In 1836, physicist Micheal Faraday built a container whose
walls were of a conducting material that was intended to
absorb and redistribute any external electrical field, so as
to cancel the field’s effect upon the interior of (and any
contents therein) of the container. See the image below. If
you think “black box” like airplanes carry, you have the
right idea. The ‘black box’ carried on airplanes are apart
from being fire and crash-resistant are a useful example of
a ‘Faraday Cage.’
Faraday Cage and Some Uses
It is probably based in some fact that some High Schools and
even proctored exams in college might use a simple Faraday
Shield in the testing hall to prevent students from cheating
by texting for answers from their cell phones, hand-held or
blackberry devices. The classroom might have the windows
covered in aluminum foil or some other similarly conductive
‘shielding’ material to prevent radio waves from being able
to penetrate into the room thus, blocking cell phone
reception.
Computers must by law not interfere with TV or radio
reception (and must accept any interference that they
receive) so again, a Faraday shield is used. The electronic
components that emit potentially disruptive EM radiation are
containerized behind either solid metal shielding or a
suitable mesh ‘envelope’ whose holes are ‘substantially
smaller’ than the frequency of radio wave that they emit.
Shielded coaxial cable is also a Faraday shield, for
incoming/outgoing signals are effectively blocked and do not
cause disruption to other external devices otherwise capable
of receiving the proximal leaked signals. A damaged or
‘partially skinned’ coaxial cable will ‘leak signal’
resulting in the device receiving poor quality reception or
display, and other non-related devices would receive leaked
static or other disruption. Television audio coming over
portable and civilian band (“CB”) radios (and vice-versa) in
the immediate vicinity comes to mind.
To protect my magnetic media (floppy disks, tapes,
ZIP-drives, etc.) from EM radiation, I use an Army Surplus
Ammo can, whose thick metal sides act as a shield to radio
waves and EM radiation. This offers at least some protection
from the computer monitor, power cables and cords, TV and
the refrigerator. There is probably some protection from
weak magnets too but I would not wish to place refrigerator
magnets on the ammo box to test the facts because thickness
and even multiple layers are required for true, 100%
protection from all Electromagnetic radiation sources.
This also explains why in an automobile accident involving
electrical power lines draped over it, it is safer to remain
inside the vehicle than trying to exist. There exists an
apocryphally bordering upon urban legend that it is the
rubber tires under the car protecting you. Not so true. It
is really the fact that you are surrounded by a ‘Faraday
cage’ of metal, which disperses the electrical strike away
and shields the interior. And again, the same with buildings
of concrete with iron rebar and plaster walls, which is also
a Faraday shield to some extent. This is why cell phones
tend to fail inside of larger buildings. Higher frequency
radio waves with ‘tighter’ or ’smaller’ sine wave troughs
can penetrate deeper through ‘holes’ in the building
(windows, cracks around doors, elevator shafts, ventilation
shafts, etc.) and thus, are becoming less prone to
suppression and dropped signal.
I want to try an experiment sometime to test my ammo box’s
ability to stop cell phone frequency. What I would do is
while playing music media here in this room, use my cell
phone to call my ‘standard’ phone in the other room. Make
the call and leave the cell phone here while I go answer the
standard phone in the other room. I should hear music
playing.
Then, return to the cell phone and place it, -still live,
into the ammo box and close the door and lock it. The cell
phone is now enclosed in a Faraday Cage/Shield. The ammo box
is not insulated so sound waves will be audible inside the
metal box, but the cell phone’s radiation (the broadcast
frequency) will be contained. Checking the ‘standard phone’
should now indicate silence, no music would be heard, as the
cell phone is no longer able to broadcast its signal out
even though the sound would still be heard inside the ammo
box. To test that, a simple mini cassette recorder placed
with the cell phone would show that yes, the ammo box is not
sound-proof. The sound would be muffled no doubt, but still
audible.
Afghanistan, Kabul
Darwin, Northern Territory
South Bend, Indiana
Erie, Pennsylvania
Rochester, Minnesota
Cotonou (de facto capital)
Armadale, Victoria
Newcastle, Australia
Sri Lanka, Colombo
Al Naslah, United Arab Emirates, Al Naslah, UAE
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