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
                      Frequency (MHz)                         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\......................................  ............
------------------------------------------------------------------------
* * * * *
\1\ Applicable 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.
\2\ See subpart G of this part for the stability requirements for
  transmitters used in the Digital Electronic Message Service.
\3\ Existing 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.
\4\ Applicable to private operational fixed point-to-point microwave and
  stations providing MVDDS.
\5\ For 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%.
\6\ For stations authorized prior to March 11, 1997, transmitter
  tolerance shall not exceed 0.03%.
\7\ The 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.
\8\ Equipment 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

[[Page 654]]

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 2004 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]