Sec.  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
   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
   27,500 to 28,350                             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.

   ^2  See  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  Sec. 101.147 and  Sec. 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  Sec. 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]