Goto Section: 101.109 | 101.113 | Table of Contents

FCC 101.111
Revised as of January 19, 2021
Goto Year:2020 | 2022
  §  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 FR 38912 , July 7, 2015]

   


Goto Section: 101.109 | 101.113

Goto Year: 2020 | 2022
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