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Consumer Information on Wireless Phones
(The following information comes from a consumer information
Website jointly sponsored by the U.S. Food and Drug Administration
(FDA) and the Federal Communications Commission (FCC), entitled
“Cell Phone Facts: Consumer Information on Wireless Phones.”The
information reproduced herein is dated April 3, 2002. For further
updates, please visit the Website:
http://www.fda.gov/cellphones/.)
1. What is radiofrequency energy (RF)?
Radiofrequency (RF) energy is another name for radio waves. It is one
form of electromagnetic energy that makes up the electromagnetic
spectrum. Some of the other forms of energy in the electromagnetic
spectrum are gamma rays, x-rays and light. Electromagnetic energy
(or electromagnetic radiation) consists of waves of electric and
magnetic energy moving together (radiating) through space. The
area where these waves are found is called an electromagnetic field.
Radio waves are created due to the movement of electrical charges in
antennas. As they are created, these waves radiate away from the
antenna. All electromagnetic waves travel at the speed of light. The
major differences between the different types of waves are the
distances covered by one cycle of the wave and the number of waves
that pass a certain point during a set time period. The wavelength is
the distance covered by one cycle of a wave. The frequency is the
number of waves passing a given point in one second. For any
electromagnetic wave, the wavelength multiplied by the frequency
equals the speed of light. The frequency of an RF signal is usually
expressed in units called hertz (Hz). One Hz equals one wave per
second. One kilohertz (kHz) equals one thousand waves per second,
one megahertz (MHz) equals one million waves per second, and one
gigahertz (GHz) equals one billion waves per second.
RF energy includes waves with frequencies ranging from about 3000
waves per second (3 kHz) to 300 billion waves per second (300 GHz).
Microwaves are a subset of radio waves that have frequencies ranging
from around 300 million waves per second (300 MHz) to three billion
waves per second (3 GHz).
Section 4: Safety Guidelines and Warranty Information
4A: Safety 121