palmOne Vision Smart Device Treo 650 User Manual page 293

Are wireless telephone base stations safe?
The electromagnetic RF signals transmitted from base station antennas stations travel toward the
horizon in relatively narrow paths. For example, the radiation pattern for an antenna array
mounted on a tower can be likened to a thin pancake centered around the antenna system. The
individual pattern for a single array of sector antennas is wedge-shaped, like a piece of pie. As
with all forms of electromagnetic energy, the power decreases rapidly as one moves away from
the antenna. Therefore, RF exposure on the ground is much less than exposure very close to the
antenna and in the path of the transmitted radio signal. In fact, ground-level exposure from such
antennas is typically thousands of times less than the exposure levels recommended as safe by
expert organizations. So exposure to nearby residents would be well within safety margins.
Cellular and PCS base stations in the United States are required to comply with limits for
exposure recommended by expert organizations and endorsed by government agencies
responsible for health and safety. Measurements made near cellular and PCS base station
antennas mounted on towers have confirmed that ground-level exposures are typically
thousands of times less than the exposure limits adopted by the FCC. In fact, in order to be
exposed to levels at or near the FCC limits for cellular or PCS frequencies an individual would
essentially have to remain in the main transmitted radio signal (at the height of the antenna) and
within a few feet from the antenna. This is, of course, very unlikely to occur.
When cellular and PCS antennas are mounted on rooftops, RF levels on that roof or on others near
by would probably be greater than those typically encountered on the ground. However, exposure
levels approaching or exceeding safety guidelines should be encountered only very close to or
directly in front of the antennas. In addition, for sector-type antennas, typically used for such
rooftop base stations, RF levels to the side and in back of these antennas are insignificant. General
guidelines on antenna installations and circumstances that might give rise to a concern about an
facility's conformance with FCC regulations can be found in A Local Government Official's Guide
to Transmitting Antenna RF Emission Safety: Rules, Procedures, and Practical Guidance. This Guide
can be accessed at:
http://www.fcc.gov/oet/rfsafety.
Safety 281