§  15.236   Operation of wireless microphones in the bands 54-72 MHz, 76-88
MHz, 174-216 MHz, 470-608 MHz and 614-698 MHz.

   (a) Definitions. The following definitions apply in this section.

   (1) Wireless Microphone. An intentional radiator that converts sound
   into electrical audio signals that are transmitted using radio signals
   to a receiver which converts the radio signals back into audio signals
   that are sent through a sound recording or amplifying system. Wireless
   microphones may be used for cue and control communications and
   synchronization of TV camera signals as defined in § 74.801 of this
   chapter. Wireless microphones do not include auditory assistance
   devices as defined in § 15.3(a) of this part.

   (2) 600 MHz duplex gap. An 11 megahertz guard band at 652-663 MHz that
   separates part 27 600 MHz service uplink and downlink frequencies.

   (3) 600 MHz guard band. Designated frequency band at 614-617 MHz that
   prevents interference between licensed services in the 600 MHz service
   band and channel 37.

   (4) 600 MHz service band. Frequencies in the 617-652 MHz and 663-698
   MHz bands that are reallocated and reassigned for 600 MHz band services
   under part 27.

   Note to paragraphs (a)(2), (3) and (4): The specific frequencies will
   be determined in light of further proceedings pursuant to GN Docket No.
   12-268 and the rules will be updated accordingly pursuant to a future
   public notice.

   (5) Spectrum Act. Title VI of the Middle Class Tax Relief and Job
   Creation Act of 2012 (Pub. L. 112-96).

   (b) Operation under this section is limited to wireless microphones as
   defined in this section.

   (c) Operation is permitted in the following frequency bands.

   (1) Channels allocated and assigned for the broadcast television
   service.

   (2) Frequencies in the 600 MHz service band on which a 600 MHz service
   licensee has not commenced operations, as defined in § 27.4 of this
   chapter. Operation on these frequencies must cease no later than the
   end of the post-auction transition period, as defined in § 27.4 of this
   chapter. Operation must cease immediately if harmful interference
   occurs to a 600 MHz service licensee.

   (3) The 657-663 MHz segment of the 600 MHz duplex gap.

   (4) [Reserved]

   (5) The 614-616 MHz segment of the 600 MHz guard band.

   (6) Prior to operation in the frequencies identified in paragraphs
   (c)(2) through (5) of this section, wireless microphone users shall
   rely on the white space databases in part 15, Subpart H to determine
   that their intended operating frequencies are available for unlicensed
   wireless microphone operation at the location where they will be used.
   Wireless microphone users must register with and check a white space
   database to determine available channels prior to beginning operation
   at a given location. A user must re-check the database for available
   channels if it moves to another location.

   (d) The maximum radiated power shall not exceed the following values:

   (1) In the bands allocated and assigned for broadcast television and in
   the 600 MHz service band: 50 mW EIRP

   (2) In the 600 MHz guard band and the 600 MHz duplex gap: 20 mW EIRP.

   (e) Operation is limited to locations separated from licensed services
   by the following distances.

   (1) Four kilometers outside the following protected service contours of
   co-channel TV stations.
   Type of station Protected contour
   Channel Contour
   (dBu) Propagation curve
   Analog: Class A TV, LPTV, translator and booster Low VHF (2-6) 47
   F(50,50)
       High VHF (7-13) 56 F(50,50)
       UHF (14-51) 64 F(50,50)
   Digital: Full service TV, Class A TV, LPTV, translator and booster Low
   VHF (2-6) 28 F(50,90)
       High VHF (7-13) 36 F(50,90)
       UHF (14-51) 41 F(50,90)

   (2) The following distances outside of the area where a 600 MHz service
   licensee has commenced operations, as defined in § 27.4 of this chapter.
           Type of station Separation distance in kilometers
   Co-
   channel Adjacent
   channel
           Base              7                          0.2
           Mobile           35                           31

   (f) The operating frequency within a permissible band of operation as
   defined in paragraph (c) must comply with the following requirements.

   (1) The frequency selection shall be offset from the upper or lower
   band limits by 25 kHz or an integral multiple thereof.

   (2) One or more adjacent 25 kHz segments within the assignable
   frequencies may be combined to form a channel whose maximum bandwidth
   shall not exceed 200 kHz. The operating bandwidth shall not exceed 200
   kHz.

   (3) The frequency tolerance of the carrier signal shall be maintained
   within ±0.005% 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. Battery operated
   equipment shall be tested using a new battery.

   (g) Emissions within the band from one megahertz below to one megahertz
   above the carrier frequency shall comply with the emission mask in § 8.3
   of ETSI EN 300 422-1 V1.4.2 (2011-08), Electromagnetic compatibility
   and Radio spectrum Matters (ERM); Wireless microphones in the 25 MHz to
   3 GHz frequency range; Part 1: Technical characteristics and methods of
   measurement. Emissions outside of this band shall comply with the
   limits specified in section 8.4 of ETSI EN 300 422-1 V1.4.2 (2011-08).

   [ 80 FR 73069 , Nov. 23, 2015, as amended at  81 FR 4974 , Jan. 29, 2016;
    82 FR 41559 , Sept. 1, 2017]