§ 15.255   Operation within the band 57-64 GHz.

   (a) Operation under the provisions of this section is not permitted for
   the following products:

   (1) Equipment used on aircraft or satellites.

   (2) Field disturbance sensors, including vehicle radar systems, unless
   the field disturbance sensors are employed for fixed operation. For the
   purposes of this section, the reference to fixed operation includes
   field disturbance sensors installed in fixed equipment, even if the
   sensor itself moves within the equipment.

   (b) Within the 57-64 GHz band, emission levels shall not exceed the
   following equivalent isotropically radiated power (EIRP):

   (1) Products other than fixed field disturbance sensors shall comply
   with one of the following emission limits, as measured during the
   transmit interval:

   (i) Except as indicated in paragraph (b)(1)(ii) of this section, the
   average power of any emission shall not exceed 40 dBm and the peak
   power of any emission shall not exceed 43 dBm.

   (ii) For transmitters located outdoors, the average power of any
   emission shall not exceed 82 dBm minus 2 dB for every dB that the
   antenna gain is less than 51 dBi. The peak power of any emission shall
   not exceed 85 dBm minus 2 dB for every dB that the antenna gain is less
   than 51 dBi. The provisions of § 15.204(c)(2) and (c)(4) of this part
   that permit the use of different antennas of the same type and of equal
   or less directional gain do not apply to intentional radiator systems
   operating under this provision. In lieu thereof, intentional radiator
   systems shall be certified using the specific antenna(s) with which the
   system will be marketed and operated. Compliance testing shall be
   performed using the highest gain and the lowest gain antennas for which
   certification is sought and with the intentional radiator operated at
   its maximum available output power level. The responsible party, as
   defined in § 2.909 of this chapter, shall supply a list of acceptable
   antennas with the application for certification.

   (2) For fixed field disturbance sensors that occupy 500 MHz or less of
   bandwidth and that are contained wholly within the frequency band
   61.0-61.5 GHz, the average power of any emission, measured during the
   transmit interval, shall not exceed 40 dBm, and the peak power of any
   emission shall not exceed 43 dBm. In addition, the average power of any
   emission outside of the 61.0-61.5 GHz band, measured during the
   transmit interval, but still within the 57-64 GHz band, shall not
   exceed 10 dBm, and the peak power of any emission shall not exceed 13
   dBm.

   (3) For fixed field disturbance sensors other than those operating
   under the provisions of paragraph (b)(2) of this section, the peak
   transmitter conducted output power shall not exceed -10 dBm and the
   peak EIRP level shall not exceed 10 dBm.

   (4) The peak power shall be measured with an RF detector that has a
   detection bandwidth that encompasses the 57-64 GHz band and has a video
   bandwidth of at least 10 MHz. The average emission levels shall be
   calculated based on the measured peak levels, over the actual time
   period during which transmission occurs. Measurement procedures that
   have been found to be acceptable to the Commission in accordance with
   § 2.947 of this chapter may be used to demonstrate compliance.

   (c) Limits on spurious emissions:

   (1) The power density of any emissions outside the 57-64 GHz band shall
   consist solely of spurious emissions.

   (2) Radiated emissions below 40 GHz shall not exceed the general limits
   in § 15.209.

   (3) Between 40 GHz and 200 GHz, the level of these emissions shall not
   exceed 90 pW/cm2 at a distance of 3 meters.

   (4) The levels of the spurious emissions shall not exceed the level of
   the fundamental emission.

   (d) Only spurious emissions and transmissions related to a
   publicly-accessible coordination channel, whose purpose is to
   coordinate operation between diverse transmitters with a view towards
   reducing the probability of interference throughout the 57-64 GHz band,
   are permitted in the 57-57.05 GHz band.

   Note to paragraph (d): The 57-57.05 GHz is reserved exclusively for a
   publicly-accessible coordination channel. The development of standards
   for this channel shall be performed pursuant to authorizations issued
   under part 5 of this chapter.

   (e) Except as specified paragraph (e)(1) of this section, the peak
   transmitter conducted output power shall not exceed 500 mW. Depending
   on the gain of the antenna, it may be necessary to operate the
   intentional radiator using a lower peak transmitter output power in
   order to comply with the EIRP limits specified in paragraph (b) of this
   section.

   (1) Transmitters with an emission bandwidth of less than 100 MHz must
   limit their peak transmitter conducted output power to the product of
   500 mW times their emission bandwidth divided by 100 MHz. For the
   purposes of this paragraph, emission bandwidth is defined as the
   instantaneous frequency range occupied by a steady state radiated
   signal with modulation, outside which the radiated power spectral
   density never exceeds 6 dB below the maximum radiated power spectral
   density in the band, as measured with a 100 kHz resolution bandwidth
   spectrum analyzer. The center frequency must be stationary during the
   measurement interval, even if not stationary during normal operation
   (e.g., for frequency hopping devices).

   (2) Peak transmitter conducted output power shall be measured with an
   RF detector that has a detection bandwidth that encompasses the 57-64
   GHz band and that has a video bandwidth of at least 10 MHz. Measurement
   procedures that have been found to be acceptable to the Commission in
   accordance with § 2.947 of this chapter may be used to demonstrate
   compliance.

   (3) For purposes of demonstrating compliance with this paragraph,
   corrections to the transmitter conducted output power may be made due
   to the antenna and circuit loss.

   (f) Frequency stability. Fundamental emissions must be contained within
   the frequency bands specified in this section during all conditions of
   operation. Equipment is presumed to operate over the temperature range
   -20 to +50 degrees Celsius with an input voltage variation of 85% to
   115% of rated input voltage, unless justification is presented to
   demonstrate otherwise.

   (g) Regardless of the power density levels permitted under this
   section, devices operating under the provisions of this section are
   subject to the radiofrequency radiation exposure requirements specified
   in § § 1.1307(b), 2.1091 and 2.1093 of this chapter, as appropriate.
   Applications for equipment authorization of devices operating under
   this section must contain a statement confirming compliance with these
   requirements for both fundamental emissions and unwanted emissions.
   Technical information showing the basis for this statement must be
   submitted to the Commission upon request.

   (h) Any transmitter that has received the necessary FCC equipment
   authorization under the rules of this chapter may be mounted in a group
   installation for simultaneous operation with one or more other
   transmitter(s) that have received the necessary FCC equipment
   authorization, without any additional equipment authorization. However,
   no transmitter operating under the provisions of this section may be
   equipped with external phase-locking inputs that permit beam-forming
   arrays to be realized.

   [ 63 FR 42279 , Aug. 7, 1998, as amended at  66 FR 7409 , Jan. 23, 2001;  68 FR 68547 , Dec. 9, 2003;  78 FR 59850 , Sept. 30, 2013]

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