Question 4: Is wireless safe?
Answer: Absolutely yes!
For organizations that have not been exposed to using wireless systems for their communication needs, the question always comes up about the safety and health risks of having wireless systems (transmitters and receivers) on their premises. Mostly driven from non-technical individuals and from legal departments comes this concern and sometimes even objection from using wireless technology. Fear driven images of people being radiated or having long term effects, such as cancer come into question. This has been mostly prominent in discussions regarding the use of cellular phones.
Wireless RF signals (radio frequency)are all around us, both man made and naturally occurring from the Earth itself. We are constantly exposed to radio waves of various frequencies at all times. Most people don't understand that. When we talk about the man made RF signals, people are concerned when the term "Microwave" is heard. Understand the term Microwave is broad definition of radio frequencies ranging from 300MHz to 300GHz and at various power levels. We think of our "microwave ovens" zapping our food until flaming hot. Microwave ovens operate at 2.45GHz at a power transmission of roughly 700W output. Most Wi-Fi and outdoor point-to-point, point-to-multipoint, Wi-Max, etc. systems operate at less than 1 Watt!
The concern then becomes about he risk of long-term exposure of RF and at what levels. Organizations, such as the Federal Communications Commission ("FCC"), Environmental Protection Agency ("EPA"), National Institute for Occupational Safety and Health, Occupational Safety and Health Administration("OSHA"), National Telecommunications and Information Administration ("NTIA") and others have performed numerous studies and consistently re-studied the effects of RF exposure on humans to answer this question. These organizations have established and set guidelines for safe levels of operation and exposure for wireless transmission.
In broadband wireless people get concerned because we are dealing with higher frequencies (e.g. 5GHz, 11GHz, 18GHz, 23GHz, 60GHz, etc) and they see antennas ranging from 1ft to 8ft on a tower. People assume that higher the frequency and larger the antenna the greater the health risk. This is just not true. For example at 60GHz the signal at 1 Watt cannot even penetrate the human skin. Again, outdoor wireless, regulated by the FCC, typically operate at extremely low levels of output power (<1W).
According to the WHO ("World Health Organization") "In fact, due to their lower frequency, at similar RF exposure levels, the body absorbs up to five times more of the signal from FM radio and television than from base stations. This is because the frequencies used in FM radio (around 100 MHz) and in TV broadcasting (around 300 to 400 MHz) are lower than those employed in mobile telephony (900 MHz and 1800 MHz) and because a person's height makes the body an efficient receiving antenna. Further, radio and television broadcast stations have been in operation for the past 50 or more years without any adverse health consequence being established." - Fact sheet N°304 May 2006 -Electromagnetic Fields and Public Health.
The greatest amount of exposure occurs in a relatively close distance to the transmitting antenna. The exposure levels drops quickly over distance. Most antenna systems are installed at higher elevation levels above where a human would normally be standing (e.g. roof tops and on towers). Installers should take precautions and limit their exposure from standing directly in front of an operating antenna. Otherwise, there has been no scientific evidence that the lower levels of RF exposure that fixed Wi-Fi and outdoor wireless emit have any effects on human health.