User guide

Radiation hazard assessment Chapter 4: Reference information
4-88
phn-2513_004v000 (Oct 2012)
These separation distances are significantly lower than those calculated by the method
specified by the FCC. The ETSI method recognises that radiation is distributed across the
antenna aperture and is not in reality a point source.
FCC method
This section evaluates the radiation levels produced by the PTP 800 products against the
following standards:
•
ANSI IEEE C95.1-1991, IEEE Standard for Safety Levels with Respect to Human
Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz.
• US FCC limits for the general population. See the FCC web site at http://www.fcc.gov
,
and the policies, guidelines, and requirements in Part 1 of Title 47 of the Code of
Federal Regulations
, as well as the guidelines and suggestions for evaluating
compliance in
FCC OET Bulletin 65 .
• Health Canada limits for the general population. See the Health Canada web site at
http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/99ehd-dhm237/limits-limites_e.html
and Safety Code 6.
• ICNIRP (International Commission on Non-Ionizing Radiation Protection) guidelines for
the general public. See the ICNIRP web site at http://www.icnirp.de/
and Guidelines for
Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields .
Calculation
FCC OET Bulletin 65 specifies the far-field method to calculate power density:
2
4 R
GP
S
π
=
Where S = Power density (W/m
2
), P = Maximum average transmit power capability of the
radio (Watts), G = Antenna gain, R = Distance from point source (meters).
FCC Title 47 Part 1.1310 defines the exposure limit for the general population to be 10
W/m
2
(1 mW/cm
2
) in the frequency range 1500 to 100,000 MHz. This defines an exposure
time of 30 minutes. Higher levels are permitted for shorter periods of exposure.
Rearranging terms to solve for distance yields:
GP
S
R
π 4
=