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Code of Federal Regulations Title 47. Telecommunication § 47.18.305 Field strength limits

Current as of October 02, 2022 | Updated by FindLaw Staff

(a) ISM equipment operating on a frequency specified in § 18.301 is permitted unlimited radiated energy in the band specified for that frequency.

(b) The field strength levels of emissions which lie outside the bands specified in § 18.301, unless otherwise indicated, shall not exceed the following:

Equipment

Operating frequency

RF Power generated by equipment (watts)

Field strength limit (uV/m)

Distance (meters)

Any type unless otherwise specified (miscellaneous).

Any ISM frequency

Below 500

25

300

500 or more

25 square root power/500

1300

Any non-ISM frequency

Below 500

15

300

500 or more

15 square root power/500

1300

Industrial heaters and RF stabilized arc welders.

On or below 5,725 MHz

Any

10

1,600

Above 5,725 MHz

Any

(2)

(2)

Medical diathermy

Any ISM frequency

Any

25

300

Any non-ISM frequency

Any

15

300

Ultrasonic

Below 490 kHz

Below 500

2,400/F(kHz)

300

500 or more

2,400/F(kHz) square root power/500

3300

490 to 1,600 kHz

Any

24,000/F(kHz)

30

Above 1,600 kHz

Any

15

30

Induction cooking ranges

Below 90 kHz

Any

1,500

430

On or above 90 kHz

Any

300

430

1 Field strength may not exceed 10 muV/m at 1600 meters. Consumer equipment operating below 1000 MHz is not permitted the increase in field strength otherwise permitted here for power over 500 watts.

2 Reduced to the greatest extent possible.

3 Field strength may not exceed 10 &b.mu;V/m at 1600 meters. Consumer equipment is not permitted the increase in field strength otherwise permitted here for over 500 watts.

4 Induction cooking ranges manufactured prior to February 1, 1980, shall be subject to the field strength limits for miscellaneous ISM equipment.

(c) The field strength limits for RF lighting devices shall be the following:

Frequency (MHz)

Field strength limit at 30 meters (&b.mu;V/m)

Non-consumer equipment:

30-88

30

88-216

50

216-1000

70

Consumer equipment:

30-88

10

88-216

15

216-1000

20

Notes

1. The tighter limit shall apply at the boundary between two frequency ranges.

2. Testing for compliance with these limits may be made at closer distances, provided a sufficient number of measurements are taken to plot the radiation pattern, to determine the major lobes of radiation, and to determine the expected field strength level at 30, 300, or 1600 meters. Alternatively, if measurements are made at only one closer fixed distance, then the permissible field strength limits shall be adjusted using 1/d as an attenuation factor.

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Cite this article: FindLaw.com - Code of Federal Regulations Title 47. Telecommunication § 47.18.305 Field strength limits - last updated October 02, 2022 | https://codes.findlaw.com/cfr/title-47-telecommunication/cfr-sect-47-18-305/

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