What is RF
Radiation?
What is RF? Topic
Navigation
[EMF Spectrum] [Ionizing]
[Non-ionizing]
[Near Field & Far Field] [RF
Hazards]
[Reflection] [Interference]
[Faraday Effect]
[ELF/EMF] [Schumann
Resonance] [DNA]
[Health Effects] [RF
Protection] [The
SCP System]
[About SAR] [Exposure
Models] [Glossary]
The word radiation is often thought of as referring to
the emanations from radioactive material and x-rays. However when scientists
use the word radiation they are usually referring to electromagnetic
radiation (EMR) which can be emitted from such sources as radio cell phones,
TV transmissions, light from the sun as well as x-ray machines.
Electromagnetic radiation has electric and magnetic field components and
passes through space at the speed of light - about 300,000,000 metres per
second (186,000 miles per second).
Microwave (MW) and radio frequency (RF) radiation is
electromagnetic radiation that is lower in frequency and therefore longer in
wavelength than infrared radiation. "Radiofrequency" is the name given to
that section of the electromagnetic spectrum from frequencies of 300 kHz to
300 GHz. In general the section of the electromagnetic spectrum from
frequencies of approximately 300 MHz to 300 GHz and wavelengths of
approximately 1 meter (m) to 1 millimeter (mm) are called microwaves.
Although some consider microwaves not to include lower frequencies and to
start at 800 MHz with a wavelength of 37.5 centimeters (cm).
The term "microwaves" can be misleading. The
wavelengths are not really "micro" in size because they range from 1 meter
to the shortest which is 1 millimeter not 1 "micro" meter. (See also
Extremely Low Frequency (ELF) and Electromagnetic Fields
(EMF's)
Sources of radio frequency and of microwaves are
primarily:
- Radio and television broadcast antenna
- Communications equipment such as
cellular & PCS,
satellite, etc.
- Cooking (microwave
ovens)
- Civilian, police and military radar
- A variety of industrial inductive and dielectric
heating devices
- Medical devices such as magnetic resonance imaging
(MRI), and diathermy devices
RF Health
Concern Classifications
The primary health concern of microwave radiation is
adverse effects associated with whole or partial body
thermal
exposure. A clear example of a
thermal exposure situation is the heating of animal tissue (e.g.
hamburger) in a microwave oven. The microwave electromagnetic radiation
"cooks" the animal tissue. Avoiding damaging thermal exposure levels is
accomplished by keeping one's exposure below recommended maximum specific
absorption rates (SAR's).
However since SAR
is difficult to determine, safety standards have also adopted maximum
allowable power density exposure limits measured in units of watts per
square meter (W/m2).
New studies suggest hazards exists at
Non-thermal levels of rf
exposure. This should be a great concern for cell phone users who want to
maximize their safety.
