ARRL has filed a Petition for Clarification addressing two issues arising from amended FCC RF safety rules that go into effect on June 1 for the Amateur Service and other FCC-regulated services. Licensees will have 2 years to determine if an RF safety evaluation is now required under the new rules and to perform an evaluation and implement any needed mitigation measures. Current rules already require amateur stations to meet RF exposure limits, but more radio amateurs will have to evaluate their stations under the new rules. The revised final rules, adopted last November, appeared in the April 1 edition of The Federal Register. 

“For applicants and licensees in the Amateur Radio Service, we substitute our general exemption criteria for the specific exemption from routine evaluation based on power alone in §97.13(c)(1) and specify the use of occupational/controlled limits for amateurs where appropriate,” the FCC said. While radio amateurs have always had to comply with RF exposure limits, certain stations have been exempted from having to conduct evaluations based upon power and frequency.

On May 8, ARRL asked the FCC to clarify that using maximum permissible exposure (MPE) limits be permitted in the Amateur Service for required RF safety evaluations of 2200-meter operations, just as they are elsewhere in the amateur spectrum. Removal of the exemption for amateurs resulted in a requirement to use specific absorption rate (SAR) limits for amateur frequencies between 100 and 300 kHz.

“SAR evaluations are very complex to directly measure and, we believe, generally exceed the capability of most individual amateur operators,” ARRL argued in its petition, asserting that MPE limits correspond to conservative estimates of SAR.

“Near-field calculation of a uniform field applied to a transmitter and antenna operating at 1 W EIRP on 2200 meters would result in a very conservative estimate of specific absorption rate (SAR) and is a valid measurement for determining safety of operation,” ARRL told the FCC. “We request clarification that the rules do not intend to preclude the use of MPE as a surrogate for SAR to evaluate amateur operations in the 2200-meter band.”

ARRL also wants the FCC to clarify that its amended rules permit the use of near-field regression rates, using the MPE table to compare against the maximum field strength that may occur from a handheld portable device, instead of using the SAR. In its filing, ARRL maintained that SAR data is not available for amateur equipment as it is for equipment used in other services. Before the rules were amended, mobile and portable transmitters generally were exempt from the requirement to perform routine environmental evaluations.

Under §97.13(c)(1) as amended, effective on June 1, amateur licensees must ensure compliance with FCC RF exposure requirements spelled out in sections 1.1307(b), 2.1091, and 2.1093 of the FCC rules, where applicable. “In lieu of evaluation with the general population/uncontrolled exposure limits, amateur licensees may evaluate their operation with respect to members of his or her immediate household using the occupational/controlled exposure limits in §1.1310, provided appropriate training and information has been accessed by the amateur licensee and members of his/her household.”

“RF exposure of other nearby persons who are not members of the amateur licensee’s household must be evaluated with respect to the general population/uncontrolled exposure limits.” The rule directs radio amateurs to OET Bulletin 65, Supplement B for methodologies and guidance to evaluate amateur radio operation.

The FCC has provided 2 years — until May 31, 2022 — for licensees to determine if evaluations are now required, to perform such evaluations where necessary, and to implement any needed mitigation measures.

“The amended rules are intended to provide more efficient, practical, and consistent RF exposure evaluation procedures and mitigation measures to help ensure compliance with the existing RF exposure limits,” the FCC said. “The amended rules replace the various inconsistent service-specific criteria for exempting parties from performing an evaluation to demonstrate compliance with the RF exposure limits with new, streamlined criteria. The amended rules also allow the use of any valid computational method to determine potential RF exposure levels. The FCC did not amend the actual RF exposure limits that were adopted in 1996.