Section 4A: Safety Guidelines 175Consumer Information on Wireless Phones(The following information comes from a consumer information Websitejointly sponsored by the U.S. Food and Drug Administration (FDA) and theFederal Communications Commission (FCC), entitled “Cell Phone Facts:Consumer Information on Wireless Phones.” The information reproducedherein is dated July 29, 2003. For further updates, please visit the Website:http://www.fda.gov/cellphones/qa.html.)What is radiofrequency energy (RF)?Radiofrequency (RF) energy is another name for radio waves. It is one form ofelectromagnetic energy that makes up the electromagnetic spectrum. Some ofthe other forms of energy in the electromagnetic spectrum are gamma rays, x-rays and light. Electromagnetic energy (or electromagnetic radiation) consistsof waves of electric and magnetic energy moving together (radiating) throughspace. 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. Allelectromagnetic waves travel at the speed of light. The major differencesbetween the different types of waves are the distances covered by one cycle ofthe wave and the number of waves that pass a certain point during a set timeperiod. The wavelength is the distance covered by one cycle of a wave. Thefrequency is the number of waves passing a given point in one second. For anyelectromagnetic wave, the wavelength multiplied by the frequency equals thespeed of light. The frequency of an RF signal is usually expressed in units calledhertz (Hz). One Hz equals one wave per second. One kilohertz (kHz) equalsone thousand waves per second, one megahertz (MHz) equals one millionwaves per second, and one gigahertz (GHz) equals one billion waves persecond.RF energy includes waves with frequencies ranging from about 3000 waves persecond (3 kHz) to 300 billion waves per second (300 GHz). Microwaves are asubset of radio waves that have frequencies ranging from around 300 millionwaves per second (300 MHz) to three billion waves per second (3 GHz).How is radiofrequency energy used?Probably the most important use of RF energy is for telecommunications. Radioand TV broadcasting, wireless phones, pagers, cordless phones, police and firedepartment radios, point-to-point links and satellite communications all rely onRF energy.Other uses of RF energy include microwave ovens, radar, industrial heaters andsealers, and medical treatments. RF energy, especially at microwavefrequencies, can heat water. Since most food has a high water content,microwaves can cook food quickly. Radar relies on RF energy to track cars andairplanes as well as for military applications. Industrial heaters and sealers useRF energy to mold plastic materials, glue wood products, seal leather itemssuch as shoes and pocketbooks, and process food. Medical uses of RF energyinclude pacemaker monitoring and programming.
