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ARRL General Bulletin ARLB050 (1996)

ARLB050 New RF standards Part 1

ARRL Bulletin 50  ARLB050
From ARRL Headquarters
Newington CT  August 6, 1996
To all radio amateurs

ARLB050 New RF standards Part 1

New FCC RF safety standards effective January 1, 1997, could affect
the way some hams operate, perhaps especially those using
vehicle-mounted antennas.  As a result of a Report and Order adopted
by the FCC on August 1 (ET Docket No. 93-62, Guidelines for
Evaluating the Environmental Effects of Radiofrequency Radiation),
Part 97 will require hams running more than 50 W PEP to conduct
routine RF radiation evaluations to determine if RF fields are
sufficient to cause human exposure to RF radiation levels in excess
of those specified. ''Measurements made during a Commission/EPA
study of several typical amateur stations in 1990 indicated that
there may be some situations where excessive exposures could
occur,'' the FCC said in ending the blanket exemption for Amateur
Radio. Amateur operation at power levels of 50 W PEP or less is
''categorically excluded'' from the exposure requirement in most
cases. Where routine evaluation indicates that the RF radiation
could be in excess of the limits, ''the licensee must take action to
prevent such an occurrence,'' the Report and Order stated. The FCC
said this could mean altering operating patterns, relocating the
antenna, revising the station's technical parameters--such as
frequency, power or emission type--or ''combinations of these and
other remedies.''

''Exactly what is involved in conducting a 'routine RF radiation
evaluation' is not yet clear,'' observed ARRL Executive Secretary
David Sumner, K1ZZ, adding that the FCC has promised to release a
revised OST/OET Bulletin Number 65, ''Evaluation Compliance with
FCC-Specified Guidelines for Human Exposure to Radiofrequency
Radiation.'' The League is now studying the 100-plus page docket, to
see if the League should seek reconsideration of any aspects of the
FCC decision. Sumner noted that the FCC expects it will not be
difficult for most amateur stations to show that the specified
limits will be met.

In the Report and Order, the Commission adopted Maximum Permissible
Exposure (MPE) limits for electric and magnetic field strength and
power density for transmitters operating at frequencies from 300 kHz
to 100 GHz. These MPE limits are generally based on recommendations
of the National Council on Radiation Protection and Measurement
(NCRP) and, in many respects, are also generally based on the
guidelines issued by the Institute of Electrical and Electronics
Engineers Inc (IEEE) and subsequently adopted by the American
National Standards Institute (ANSI) as an ANSI standard (ANSI/IEEE
C95.1-1992). The Commission used the 1992 ANSI/IEEE standards
instead of the 1982 ANSI standards that had formed the basis for the
existing rules under which Amateur Radio stations were categorically

Sumner said that for high-power mobile operation and for operation
with indoor antennas, particularly in apartment buildings and other
situations where there is ''uncontrolled exposure'' to neighbors and
the general public, ''amateurs may well have to make changes in how
they operate.'' He said the ARRL Lab staff and the RF Safety
Committee will be evaluating the new requirements.

(continued in Part 2)


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