§  101.107   Frequency tolerance.

   (a) The carrier frequency of each transmitter authorized in these
   services must be maintained within the following percentage of the
   reference frequency except as otherwise provided in paragraph (b) of
   this section or in the applicable subpart of this part (unless
   otherwise specified in the instrument of station authorization the
   reference frequency will be deemed to be the assigned frequency):
     Frequency (MHz)    Frequency tolerance (percent)
   928 to 929^5                                0.0005
   932 to 932.5                               0.00015
   932.5 to 935                               0.00025
   941 to 941.5                               0.00015
   941.5 to 944                               0.00025
   952 to 960^5                                0.0005
   1,850 to 1,990                               0.002
   2,110 to 2,200                               0.001
   2,450 to 2,500^1                             0.001
   3,700 to 4,200^1                             0.005
   5,925 to 6,875^1                             0.005
   6,875 to 7,125^1                              0.005
   10,550 to 11,700^1 2                         0.005
   11,700 to 12,200^1                           0.005
   12,200 to 13,250^4                           0.005
   14,200 to 14,400                              0.03
   17,700 to 18,820^3                           0.003
   18,820 to 18,920^3                           0.001
   928 to 929^5                                0.0005
   18,920 to 19,700^3                           0.003
   19,700 to 27,500^4 7                         0.001
   29,100 to 29,250                             0.001
   31,000 to 31,300^6                           0.001
   31,300 to 40,000^4                            0.03
   71,000 to 76,000^8
   81,000 to 86,000^8
   92,000 to 95,000^8

   ^1Applicable only to common carrier LTTS stations. Tolerance for
   2450-2500 MHz is 0.005%. Beginning Aug. 9, 1975, this tolerance will
   govern the marketing of LTTS equipment and the issuance of all such
   authorizations for new radio equipment. Until that date new equipment
   may be authorized with a frequency tolerance of .03% in the frequency
   range 2,200 to 10,500 MHz and .05% in the range 10,500 MHz to 12,200
   MHz, and equipment so authorized may continue to be used for its life
   provided that it does not cause interference to the operation of any
   other licensee. Beginning March 1, 2005, new LTTS operators will not be
   licensed and existing LTTS licensees will not be renewed in the
   11.7-12.2 GHz band.

   ^2See subpart G of this part for the stability requirements for
   transmitters used in the Digital Electronic Message Service.

   ^3Existing type accepted equipment with a frequency tolerance of ±0.03%
   may be marketed until December 1, 1988. Equipment installed and
   operated prior to December 1, 1988 may continue to operate after that
   date with a minimum frequency tolerance of ±0.03%. However, the
   replacement of equipment requires that the current tolerance be met.

   ^4Applicable to private operational fixed point-to-point microwave and
   stations providing MVDDS.

   ^5For private operational fixed point-to-point microwave systems, with
   a channel greater than or equal to 50 KHz bandwidth, ±0.0005%; for
   multiple address master stations, regardless of bandwidth, ±0.00015%;
   for multiple address remote stations with 12.5 KHz bandwidths,
   ±0.00015%; for multiple address remote stations with channels greater
   than 12.5 KHz bandwidth, ±0.0005%.

   ^6For stations authorized prior to March 11, 1997, transmitter
   tolerance shall not exceed 0.03%.

   ^7The frequency tolerance for stations authorized on or before April 1,
   2005 is 0.03%. Existing licensees and pending applicants on that date
   may continue to operate after that date with a frequency tolerance of
   0.03%, provided that it does not cause harmful interference to the
   operation of any other licensee. For analog systems, if the channel
   bandwidth is greater than 30 MHz up to 50 MHz, the frequency tolerance
   standard will be 0.03%; if the channel bandwidth is 30 MHz or less,
   then the frequency tolerance standard will be 0.003%. This analog
   standard is conditional provided that harmful interference is not
   caused to digital stations operating within the 0.001% tolerance
   standards. If harmful interference is caused to stations operating with
   the more stringent standard, the onus shall be on the operators with
   the less stringent parameters to develop an engineering solution to the
   problem. For exceptions, see § 101.147 and § 101.507.

   ^8Equipment authorized to be operated in the 71,000-76,000 MHz,
   81,000-86,000 MHz, 92,000-94,000 MHz and 94,100-95,000 MHz bands is
   exempt from the frequency tolerance requirement noted in the table of
   paragraph (a) of this section.

   (b) Heterodyne microwave radio systems may be authorized at a somewhat
   less restrictive frequency tolerance (up to .01 percent) to compensate
   for frequency shift caused by numerous repeaters between base band
   signal insertion. Where such relaxation is sought, applicant must
   provide all calculations and indicate the desired tolerance over each
   path. In such instances the radio transmitters and receivers used must
   individually be capable of complying with the tolerance specified in
   paragraph (a) of this section. Heterodyne operation is restricted to
   channel bandwidth of 10 MHz or greater.

   (c) As an additional requirement in any band where the Commission makes
   assignments according to a specified channel plan, provisions must be
   made to prevent the emission included within the occupied bandwidth
   from radiating outside the assigned channel at a level greater than
   that specified in § 101.111.

   [ 61 FR 26677 , May 28, 1996, as amended at  62 FR 23167 , Apr. 29, 1997;
    63 FR 6105 , Feb. 6, 1998;  63 FR 9448 , Feb. 25, 1998;  63 FR 14039 , Mar.
   24, 1998;  63 FR 36611 , July 7, 1998;  66 FR 35110 , July 3, 2001;  67 FR 43038 , June 26, 2002;  68 FR 4956 , Jan. 31, 2003;  69 FR 3266 , Jan. 23,
   2004;  69 FR 16832 , Mar. 31, 2004;  70 FR 4787 , Jan. 31, 2005;  76 FR 59572 , Sept. 27, 2011;  81 FR 79945 , Nov. 14, 2016]