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ARRL General Bulletin ARLB070 (1997)

ARLB070 FCC issues RF safety Supplement B to OET Bulletin 65

ARRL Bulletin 70  ARLB070
From ARRL Headquarters
Newington CT  November 19, 1997
To all radio amateurs

ARLB070 FCC issues RF safety Supplement B to OET Bulletin 65

Hams now have basic guidelines and tools to evaluate their stations
for compliance with the FCC's RF exposure guidelines that go into
effect January 1, 1998.  The FCC's Office of Engineering and
Technology issued the long-anticipated Amateur Radio Supplement B on
November 18.  The FCC worked closely with the Amateur Radio
community to develop the new supplement.  Several ARRL Headquarters
staff members and Technical Advisors reviewed preliminary drafts of
the supplement. ARRL Lab Supervisor Ed Hare, W1RFI, has been the
League's point man for RF safety and exposure issues.

Supplement B, subtitled Additional Information for Amateur Radio
Stations, contains detailed information specific to ham radio
stations.  It is designed to be used in conjunction with the FCC's
OET Bulletin 65 (Version 97-01), Evaluating Compliance with FCC
Guidelines for Human Exposure to Radiofrequency Electromagnetic
Fields.  The revised Bulletin 65 was issued earlier this year.
Supplement B covers definitions of RF radiation and discusses the
FCC exposure guidelines and their applications, methods of
predicting human exposure, estimating compliance distances, and
controlling exposure to RF fields.

The supplement runs approximately 70 pages. Among its noteworthy
highlights are numerous easy-to-use tables based on various
frequencies, power levels and antenna configurations to help hams
determine whether their stations comply with the FCC's published RF
exposure guidelines.  Most tables show compliance distance--the
distance that an antenna needs to be located from areas of exposure
to be in compliance.  (For a closer look, see ''FCC RF-Exposure
Regulations--the Station Evaluation,'' by Ed Hare, W1RFI, which will
appear in the January issue of QST.)

The new RF exposure rules go into effect January 1, 1998 for all new
stations and for those filing a Form 610 with the FCC after that
date.  Existing stations have until September 1, 2000 to comply with
the new rules.  But, existing stations making changes that could
affect RF exposure from their station--such as increasing power or
relocating antennas--must evaluate that change if done after January
1, 1998.

As first announced, the FCC set a power threshold of 50 W to trigger
the need to do a station evaluation.  In late August, the FCC
revised the power level thresholds to trigger a routine Amateur
Radio station RF exposure evaluation.  Those changes were welcome
news for most hams.  The newest guidelines raised its original 50-W
threshold on all bands except 10 meters through 2 meters, where it
remains at 50 W.

The FCC went along in part with an ARRL request and established a
sliding scale for threshold levels dependent upon frequency.  The
revised thresholds are 500 W for 160 through 40 meters, 425 W on 30
meters (the maximum legal power is 200 W), 125 W on 17 meters, 100 W
on 15 meters, 75 W on 12 meters and 50 W on 10 meters.  The
threshold for all VHF bands is 50 W.  On UHF, the threshold level is
70 W on 70 cm, 150 W on 33 cm, 200 W on 23 cm, and 250 W on 13 cm
and higher frequencies.

The threshold for amateur repeaters is 500 W effective radiated
power (ERP) if the repeater antenna is located on a building or is
less than 10 meters above ground.

Stations operating at or below these respective power levels are
categorically excluded from having to conduct a routine RF radiation
evaluation.  Mobile and portable (hand-held) devices using
push-to-talk operation generally are also exempt from evaluation.
But, all stations--regardless of power level--still must comply with
the RF exposure limits that become effective New Year's Day.

OET Bulletin 65 and the new Supplement B are available at
Copies are available from International Transcription Service Inc,
1231 20th St NW, Washington, DC 20036; tel 202-857-3800; fax


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