User manual

Section 4: Safety Guidelines and Warranty Information
4A: Safety 117
11. 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.