§ 101.111   Emission limitations.

   (a) The mean power of emissions must be attenuated below the mean output
   power of the transmitter in accordance with the following schedule:

   (1) When using transmissions other than those employing digital modulation
   techniques:

   (i) On any frequency removed from the assigned frequency by more than 50
   percent up to and including 100 percent of the authorized bandwidth: At
   least 25 decibels;

   (ii) On any frequency removed from the assigned frequency by more than 100
   percent up to and including 250 percent of the authorized bandwidth: At
   least 35 decibels;

   (iii) On any frequency removed from the assigned frequency by more than 250
   percent of the authorized bandwidth: At least 43 + 10 Log10 (mean output
   power  in  watts)  decibels,  or  80 decibels, whichever is the lesser
   attenuation.

   (2) When using transmissions employing digital modulation techniques (see
   § 101.141(b)) in situations not covered in this section:

   (i) For operating frequencies below 15 GHz, in any 4 KHz band, the center
   frequency of which is removed from the assigned frequency by more than 50
   percent up to and including 250 percent of the authorized bandwidth: As
   specified by the following equation but in no event less than 50 decibels:

   A = 35 + 0.8(P −50) + 10 Log10 B. (Attenuation greater than 80 decibels or
   to an absolute power of less than −13 dBm/1MHz is not required.) where:

   A = Attenuation (in decibels) below the mean output power level.

   P = Percent removed from the center frequency of the transmitter bandwidth.

   B = Authorized bandwidth in MHz.

   Note: MVDDS operations in the 12.2-12.7 GHz band shall use 24 megahertz for
   the value of B in the emission mask equation set forth in this section. The
   emission mask limitation shall only apply at the 12.2-12.7 GHz band edges
   and does not restrict MVDDS channelization bandwidth within the band.

   (ii) For operating frequencies above 15 GHz, in any 1 MHz band, the center
   frequency of which is removed from the assigned frequency by more than 50
   percent up to and including 250 percent of the authorized bandwidth: As
   specified by the following equation but in no event less than 11 decibels:

   A = 11 + 0.4(P−50) + 10 Log10 B. (Attenuation greater than 56 decibels or to
   an absolute power of less than −13 dBm/1MHz is not required.)

   (iii) In any 1 MHz band, the center frequency of which is removed from the
   assigned frequency by more than 250 percent of the authorized bandwidth: At
   least  43  + 10 Log10 (the mean output power in watts) decibels, or 80
   decibels, whichever is the lesser attenuation. The authorized bandwidth
   includes  the  nominal  radio  frequency  bandwidth  of  an individual
   transmitter/modulator in block-assigned bands. Equipment licensed prior to
   April 1, 2005 shall only be required to meet this standard in any 4 kHz
   band.

   (iv)  The  emission mask for LMDS and the 24 GHz Service shall use the
   equation in paragraph (a)(2)(ii) of this section and apply it only to the
   band edge of each block of spectrum, but not to subchannels established by
   licensees. The value of P in the equation is the percentage removed from the
   carrier frequency and assumes that the carrier frequency is the center of
   the actual bandwidth used. The emission mask can be satisfied by locating a
   carrier of the subchannel sufficiently far from the channel edges so that
   the emission levels of the mask are satisfied. The LMDS or 24 GHz emission
   mask shall use a value B (bandwidth) of 40 MHz, for all cases even in the
   case where a narrower subchannel is used (for instance the actual bandwidth
   is 10 MHz) and the mean output power used in the calculation is the sum of
   the output power of a fully populated channel. For block assigned channels,
   the out-of-band emission limits apply only outside the assigned band of
   operation and not within the band.

   (v) The emission mask for the 71-76 GHz, 81-86 GHz, 92-94 GHz, and 94.1-95
   GHz bands used in the equation in paragraph (a)(2)(ii) of this section
   applies  only  to  the  edge  of each channel, but not to sub-channels
   established  by  licensees.  The value of P in the equation is for the
   percentage removed from the carrier frequency and assumes that the carrier
   frequency is the center of the actual bandwidth used. The value of B will
   always be 500 MHz. In the case where a narrower sub-channel is used within
   the assigned bandwidth, such sub-carrier will be located sufficiently far
   from the channel edges to satisfy the emission levels of the mask. The mean
   output power used in the calculation is the sum of the output power of a
   fully populated channel.

   (3) For Digital Termination System channels used in the Digital Electronic
   Message Service (DEMS) operating in the 10,550-10,680 MHz band:

   (i) In any 4 KHz band, the center frequency of which is removed from the
   edge  of  the DEMS channel by up to and including 1.125 times the DEMS
   subchannel bandwidth: As specified by the following equation may in no event
   be less than 50 + 10 log10 N decibels:

   A = 50 + 0.0333(F − 0.5B) + 10 log10 N decibels

   Where:

   A = Attenuation (in decibels) below means output power level contained
   within the DEMS channel for a given polarization.

   B = Bandwidth of DEMS channel (in KHz).

   F = Absolute value of the difference between the center frequency of the 4
   KHz band measured and the center frequency of the DEMS channel (in KHz).

   N = Number of active subchannels of the given polarization within the DEMS
   channel.

   (ii) In any 4 KHz band within the authorized DEMS band the center frequency
   of which is removed from the center frequency of the DEMS channel by more
   than the sum of 50% of the DEMS channel bandwidth plus 1.125 times the
   subchannel bandwidth: As specified by the following equation but in no event
   less than 80 decibels:

   A = 80 + 10 log10 N decibels

   (iii)  In  any 4 KHz band the center frequency of which is outside the
   authorized DEMS band: At least 43 + 10 log10 (mean output power in watts)
   decibels.

   (4) For DEMS channels in the 17,700-19,700 MHz band:

   (i) In any 4 KHz band, the center frequency of which is removed from the
   frequency of the center of the DEMS channel by more than 50 percent of the
   DEMS channel bandwidth up to and including 50 percent plus 500 KHz: As
   specified by the following equation but in no event be less than 50 + 10
   log10 N decibels:

   A = 50 + 0.06(F −0.5B) + 10 log10 N decibels

   Where:

   A = Attenuation (in decibels) below means output power level contained
   within the DEMS channel for a given polarization.

   B = Bandwidth of DEMS channel (in KHz).

   F = Absolute value of the difference between the center frequency of the 4
   KHz band measured and the center frequency of the DEMS channel (in KHz).

   N = Number of active subchannels of the given polarization within the DEMS
   channel.

   (ii) In any 4 KHz band within the authorized DEMS band, the center frequency
   of which is removed from the center frequency of the DEMS channel by more
   than  the  sum of 50 percent of the channel bandwidth plus 500 KHz: As
   specified by the following equation but in no event less than 80 decibels:

   A = 80 + 10 log10 N decibels

   (iii)  In  any 4 KHz band the center frequency of which is outside the
   authorized Digital Message Service band: At least 43 + 10 log10 (mean output
   power in watts) decibels.

   (5) When using transmissions employing digital modulation techniques on the
   900 MHz multiple address frequencies with a 12.5 KHz bandwidth, the power of
   any emission must be attenuated below the unmodulated carrier power of the
   transmitter (P) in accordance with the following schedule:

   (i) On any frequency removed from the center of the authorized bandwidth by
   a  displacement  frequency  (fd in KHz) of more than 2.5 KHz up to and
   including 6.25 KHz: At least 53 log10 (fd/2.5) decibels;

   (ii) On any frequency removed from the center of the authorized bandwidth by
   a  displacement  frequency (fd in KHz) of more than 6.25 KHz up to and
   including 9.5 KHz: At least 103 log10 (fd/3.9) decibels;

   (iii) On any frequency removed from the center of the authorized bandwidth
   by a displacement frequency (fd in KHz) of more than 9.5 KHz up to and
   including 15 KHz: At least 157 log10 (fd/5.3) decibels; and

   (iv) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency greater than 15 KHz: At least 50 plus 10 log10(P)
   or 70 decibels, whichever is the lesser attenuation.

   (6) When using transmissions employing digital modulation techniques on the
   900 MHz multiple address frequencies with a bandwidth greater than 12.5 KHz,
   the power of any emission must be attenuated below the unmodulated carrier
   power of the transmitter (P) in accordance with the following schedule:

   (i) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (fd in KHz) of more than 5 KHz up to and including
   10 KHz: At least 83 log10 (fd/5) decibels;

   (ii) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (fd in KHz) of more than 10 KHz up to and including
   250  percent  of the authorized bandwidth: At least 116 log10 (fd/6.1)
   decibels or 50 plus 10 log10 (P) or 70 decibels, whichever is the lesser
   attenuation; and

   (iii) On any frequency removed from the center of the authorized bandwidth
   by more that 250 percent of the authorized bandwidth: At least 43 plus 10
   log10 (output power in watts) decibels or 80 decibels, whichever is the
   lesser attenuation.

   (b) When an emission outside of the authorized bandwidth causes harmful
   interference,  the  Commission may, at its discretion, require greater
   attenuation than specified in paragraph (a) of this section.

   (c) The emission of an unmodulated carrier is prohibited except for test
   purposes as required for proper station and system maintenance.

   (d) Interference to passive sensors. These limitations are necessary to
   minimize  the  probability of harmful interference to reception in the
   10.6-10.68 GHz and 31-31.3 GHz bands onboard space stations in the Earth
   exploration-satellite service (passive).

   (1) 10.6-10.68 GHz. (i) Fixed stations are restricted to point-to-point
   operations, with each station supplying not more than ^3 dBW of transmitter
   power to the antenna, producing not more than 40 dBW of EIRP, and radiating
   at an antenna main beam elevation angle of 20° or less. Licensees holding a
   valid authorization on August 6, 2015 to operate in this band may continue
   to operate as authorized, subject to proper license renewal. Licensees are
   urged to:

   (A) Limit the maximum transmitter power supplied to the antenna to ^15 dBW;
   and

   (B) Employ automatic transmitter power control (ATPC).

   (ii) The maximum transmitter power supplied to the antenna of stations using
   ATPC may be increased by a value corresponding to the ATPC range, up to a
   maximum of −3 dBW.

   (2) 31-31.3 GHz. For fixed stations authorized after August 6, 2018, the
   unwanted emissions power in any 100 MHz of the 31.3-31.5 GHz band shall be
   limited  to −38 dBW (−38 dBW/100 MHz), as measured at the input to the
   antenna.

   [ 61 FR 26677 , May 28, 1996, as amended at  62 FR 24582 , May 6, 1997;  65 FR 59358 , Oct. 5, 2000;  67 FR 43038 , June 26, 2002;  68 FR 4957 , Jan. 31, 2003;
    69 FR 3266 , Jan. 23, 2004;  69 FR 31746 , June 7, 2004; 80 38912, July 7,
   2015]

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