Center for Safer Wireless
Promoting Safety in Our Wireless World

How Does A Cell Phone Work?

Cell phones operate across a network of cellular sites called base stations.  When using a cellular phone, sound signals are transmitted in radio frequencies and microwave frequencies with transmitters very close to the user’s head. Cell phones use a distant base unit, a cell phone antenna, as a means to receive and send communications in a laser-like beam of radiation to and from the cell phone.  If you are in a car and using a cell phone, the cell phone locks on to different antennas as the car moves. As the car nears a cell phone antenna in the same cell phone network, less radiofrequency radiation is required by the cell phone to receive and send signals to the antenna. But as the car moves away, the cell phone uses more radiofrequency radiation to seek the closest antenna.  These phones transmit at frequencies in the microwave range of 800 and 1900 megahertz. 

Both RF and ELF are concerns with using a cell phone. There is a near-field and far field plume of radiation emitted when a cell phone is in use.  According to the book Radiation Rescue, the near field radiates about a foot from the antenna , with the most intense plume in a 7 inch diameter circle around the antenna.   As the picture illustrates, when using a cell phone, radiofrequency radiation penetrates approximately 2 inches into the adult brain. More radiation is absorbed in the brains of children talking on a cell phone placed to their ears.  The far field radiofrequency radiation passes through almost everything in its course to a receiver.

In addition, the switching battery pack on a cell phone creates very high levels of extremely low frequency electromagnetic fields (ELF). 

PDAs such as Blackberries and iPhones produce higher levels than cell phones of extremely low frequency emissions because they use more energy from the battery.  Energy increases during the sending and receiving email, large files, and photos .  ELF on these PDAs have been recorded from 20 (milligauss) mG to 200 mG.  

According to CTIA – the Wireless Association, 89% of the U.S. households use cell phones as of June 2009, compared to 11% in 1995.  In addition, 20% of U.S. households are wireless-only households through June 2009. In the first half of 2008, cell-phone users in the United States spent on average 13 hours a month talking on their phones, according to CTIA.
Check your cell phone manual. It most likely says keep the phone .6 inches from your body.  Do you see cell phone commercials with people placing the phone slightly off the ear?
Recommendations for Safer Cell Phone Use


Minimize the time spent talking on a cell phone.

Use an air tube headset (different than a blue tooth)when talking.

Use the speakerphone.

Text information.

When not in use, keep your phone away from your body in a purse or bag.

Keep a cell phone off or away from your bedroom at night.

Allow older children to text and only speak on the phone in an emergency.

Don’t talk on a cell phone in a car, bus or train. Higher levels of radiofrequency radiation are required by the cell phone as it moves from and locks on one base station to the next antenna in your cell phone network.  Learn more.

Avoid wearing metal-rimmed glasses when speaking on a cell phone.  Metal attracts radiofrequency radiation that can be absorbed by the eye.

Keep cell phones away from small children.

Don't talk on your cell phone when it has weak signal strength.
Don't text and drive.

Health and Safety Testing

Cell phones were not tested for health and safety effects prior to their 1984 entry in the market. Once a cancer victim who believed the cancer was caused by cell phones attempted to sue the cell phone industry, in 1993 a $25 million research and surveillance program was developed and funded by the cell phone industry. Dr. George Carlo lead this effort that by 2001 showed red flags of warning that cell phone radiation could lead to the development of brain tumors, other cancers, or other adverse health effects.  Research, funded primarily by the cell phone industry, is ongoing.   

While the U.S. Food and Drug Administration website states, “The scientific evidence does not show a danger to any users of cell phones from radiofrequency radiation exposure, including children and teenagers… But more research is needed”, we don’t know whether cell phones will cause health abnormalities over the long-term.  Fourteen research studies covering 10 years or longer shows an increase risk of developing a glioma or acoustic neuroma on the same side of the head as a cell phone is used. 

With 4 billion cell phone users across the world and beginning evidence of long-term health effects, the Center for Safer Wireless recommends taking precautions when using a cell phone. 

Neurosurgeons and epidemiologists share their observations about brain tumors and children in the video vault of this website.

Today Tonight segment from television show in Australia tests radiation levels of cell phones. 9 minute video from August 2008.