Wireless N2WLAX-5G3 User Manual

Microwave Antenna Radiation Warning

Designed for point-to-point operation, a Link AX microwave radio system uses directional
antennas to transmit and receive microwave signals. These directional antennas are usually
circular or rectangular in shape, and are usually mounted outdoors on a tower or mast,well
above ground level.

Referencing OET Bulletin 65 (Edition 97-01,August 1997)from the Federal Communication
Commission ’s Office of Engineering &Technology, limits for maximum permissible exposure
(MPE)to microwave signals have been adopted by the FCC for General Population/Uncon-

trolled environments. This limit is 1.0 mW/cm
The closer you are to the front center-point of a microwave antenna,the greater the power

density of its transmitted microwave signal.Unless you are very close,however,microwave
exposure levels will fall far below the MPE limits.To determine how close to a microwave
antenna you can be and still remain below the MPE limits noted above,“worst case ” predictions

of the field strength and power density levels in the vicinity of an Link AX ™ microwave antenna
can be made from the following calculations. The equation is generally accurate in the far-field
of an antenna, and will over-predict power density in the near-field (i.e.close to the antenna).

2

,with averaging times of thirty-minutes.

S =PG/4πR
where:S =power density (in mW/cm

2

2

)

P =power input to the antenna (mW)
G =power gain of the antenna in the direction of interest relative to an isotropic
radiator
R =distance to the center of radiation of the antenna (cm)

Note that G,the power gain factor,is usually expressed in logarithmic terms (i.e.,dB),and must
be converted using the following equation:

G =10

dBi/10

For example,a logarithmic power gain of 17.5 dB is equal to a numeric gain of 56.23.
Assuming (1)maximum output power from the Link AX (+12 dBm [15.8 mW ]),(2)no signal loss

in the cable connecting the Link AX to the antenna,and (3)the use of a 17.5 dBi gain flat panel
antenna,the 1.0 mW/cm 2 MPE power density limit would be reached at a distance of
approximately 8.4 cm. The Link AX is classified as a fixed installation product ,and per FCC
policy guidelines regarding MPE, antennas used for this Wireless Inc. transmitter must be
installed to provide a separation distance of 1.5 meters (5 feet)or more from all persons during
normal operation to satisfy FCC RF exposure compliance.

Wireless,Inc. fully supports the FCC ’s adopted MPE limits, and recommends that personnel
maintain appropriate distances from the front of all directional microwave antennas. Should you
have questions about Link AX microwave signal radiation, please contact the Wireless, Inc.
Customer Service Department.