§ 15.249   Operation within the bands 902-928 MHz, 2400-2483.5 MHz, 5725-5875
MHZ, and 24.0-24.25 GHz.

   (a) Except as provided in paragraph (b) of this section, the field
   strength of emissions from intentional radiators operated within these
   frequency bands shall comply with the following:
   Fundamental frequency Field strength of fundamental (millivolts/meter)
   Field strength of harmonics (microvolts/meter)
   902-928 MHz                                                         50  500
   2400-2483.5 MHz                                                     50  500
   5725-5875 MHz                                                       50  500
   24.0-24.25 GHz                                                     250 2500

   (b) Fixed, point-to-point operation as referred to in this paragraph
   shall be limited to systems employing a fixed transmitter transmitting
   to a fixed remote location. Point-to-multipoint systems,
   omnidirectional applications, and multiple co-located intentional
   radiators transmitting the same information are not allowed. Fixed,
   point-to-point operation is permitted in the 24.05-24.25 GHz band
   subject to the following conditions:

   (1) The field strength of emissions in this band shall not exceed 2500
   millivolts/meter.

   (2) The frequency tolerance of the carrier signal shall be maintained
   within +-0.001% of the operating frequency over a temperature variation
   of -20 degrees to +50 degrees C at normal supply voltage, and for a
   variation in the primary supply voltage from 85% to 115% of the rated
   supply voltage at a temperature of 20 degrees C. For battery operated
   equipment, the equipment tests shall be performed using a new battery.

   (3) Antenna gain must be at least 33 dBi. Alternatively, the main lobe
   beamwidth must not exceed 3.5 degrees. The beamwidth limit shall apply
   to both the azimuth and elevation planes. At antenna gains over 33 dBi
   or beamwidths narrower than 3.5 degrees, power must be reduced to
   ensure that the field strength does not exceed 2500 millivolts/meter.

   (c) Field strength limits are specified at a distance of 3 meters.

   (d) Emissions radiated outside of the specified frequency bands, except
   for harmonics, shall be attenuated by at least 50 dB below the level of
   the fundamental or to the general radiated emission limits in § 15.209,
   whichever is the lesser attenuation.

   (e) As shown in § 15.35(b), for frequencies above 1000 MHz, the field
   strength limits in paragraphs (a) and (b) of this section are based on
   average limits. However, the peak field strength of any emission shall
   not exceed the maximum permitted average limits specified above by more
   than 20 dB under any condition of modulation. For point-to-point
   operation under paragraph (b) of this section, the peak field strength
   shall not exceed 2500 millivolts/meter at 3 meters along the antenna
   azimuth.

   [ 54 FR 17714 , Apr. 25, 1989, as amended at  55 FR 25095 , June 20, 1990;
    67 FR 1625 , Jan. 14, 2002;  77 FR 4914 , Feb. 1, 2012]

   return arrow Back to Top