§  15.109   Radiated emission limits.

   (a) Except for Class A digital devices, the field strength of radiated
   emissions from unintentional radiators at a distance of 3 meters shall
   not exceed the following values:
   Frequency of emission (MHz) Field strength (microvolts/meter)
   30–88                                                     100
   88–216                                                    150
   216–960                                                   200
   Above 960                                                 500

   (b) The field strength of radiated emissions from a Class A digital
   device, as determined at a distance of 10 meters, shall not exceed the
   following:
   Frequency of emission (MHz) Field strength (microvolts/meter)
   30–88                                                      90
   88–216                                                    150
   216–960                                                   210
   Above 960                                                 300

   (c) In the emission tables above, the tighter limit applies at the band
   edges. Sections 15.33 and 15.35 which specify the frequency range over
   which radiated emissions are to be measured and the detector functions
   and other measurement standards apply.

   (d) For CB receivers, the field strength of radiated emissions within
   the frequency range of 25–30 MHz shall not exceed 40 microvolts/meter
   at a distance of 3 meters. The field strength of radiated emissions
   above 30 MHz from such devices shall comply with the limits in
   paragraph (a) of this section.

   (e) Carrier current systems used as unintentional radiators or other
   unintentional radiators that are designed to conduct their radio
   frequency emissions via connecting wires or cables and that operate in
   the frequency range of 9 kHz to 30 MHz, including devices that deliver
   the radio frequency energy to transducers, such as ultrasonic devices
   not covered under part 18 of this chapter, shall comply with the
   radiated emission limits for intentional radiators provided in § 15.209
   for the frequency range of 9 kHz to 30 MHz. As an alternative, carrier
   current systems used as unintentional radiators and operating in the
   frequency range of 525 kHz to 1705 kHz may comply with the radiated
   emission limits provided in § 15.221(a). At frequencies above 30 MHz,
   the limits in paragraph (a), (b), or (g) of this section, as
   appropriate, apply.

   (f) For a receiver which employs terminals for the connection of an
   external receiving antenna, the receiver shall be tested to demonstrate
   compliance with the provisions of this section with an antenna
   connected to the antenna terminals unless the antenna conducted power
   is measured as specified in § 15.111(a). If a permanently attached
   receiving antenna is used, the receiver shall be tested to demonstrate
   compliance with the provisions of this section.

   (g) As an alternative to the radiated emission limits shown in
   paragraphs (a) and (b) of this section, digital devices may be shown to
   comply with the standards contained in Third Edition of the
   International Special Committee on Radio Interference (CISPR), Pub. 22,
   “Information Technology Equipment—Radio Disturbance
   Characteristics—Limits and Methods of Measurement” (incorporated by
   reference, see § 15.38). In addition:

   (1) The test procedure and other requirements specified in this part
   shall continue to apply to digital devices.

   (2) If, in accordance with § 15.33 of this part, measurements must be
   performed above 1000 MHz, compliance above 1000 MHz shall be
   demonstrated with the emission limit in paragraph (a) or (b) of this
   section, as appropriate. Measurements above 1000 MHz may be performed
   at the distance specified in the CISPR 22 publications for measurements
   below 1000 MHz provided the limits in paragraphs (a) and (b) of this
   section are extrapolated to the new measurement distance using an
   inverse linear distance extrapolation factor (20 dB/decade), e.g., the
   radiated limit above 1000 MHz for a Class B digital device is 150 uV/m,
   as measured at a distance of 10 meters.

   (3) The measurement distances shown in CISPR Pub. 22, including
   measurements made in accordance with this paragraph above 1000 MHz, are
   considered, for the purpose of § 15.31(f)(4) of this part, to be the
   measurement distances specified in this part.

   (4) If the radiated emissions are measured to demonstrate compliance
   with the alternative standards in this paragraph, compliance must also
   be demonstrated with the conducted limits shown in § 15.107(e).

   (h) Radar detectors shall comply with the emission limits in paragraph
   (a) of this section over the frequency range of 11.7–12.2 GHz.

   [ 54 FR 17714 , Apr. 25, 1989, as amended at  56 FR 373 , Jan. 4, 1991;  58 FR 51249 , Oct. 1, 1993;  66 FR 19098 , Apr. 13, 2001;  67 FR 48993 , July
   29, 2002;  69 FR 2849 , Jan. 21, 2004]