1. (a) The frequency tolerance requirements applicable to transmitters in the maritime services are shown in the following table. Tolerances are given as parts in 10 ⁶ unless shown in Hz.

   Frequency bands and categories of stations	Tolerances
   (1) Band 100-525 kHz:
   (i) Coast stations:
   For single sideband emissions	20 Hz.
   For transmitters with narrow-band direct printing and data emissions	10 Hz.1
   For transmitters with digital selective calling emissions	10 Hz.
   For all other emissions	100.
   (ii) Ship stations:
   For transmitters with narrow-band direct printing and data emissions	20 Hz.
   For transmitters with digital selective calling emissions	10 Hz.1
   For all other transmitters	10 Hz.
   (iii) Ship stations for emergency only:
   For all emissions	20 Hz.
   (iv) Survival craft stations:
   For all emissions	20 Hz.
   (v) Radiodetermination stations:
   For all emissions	100.
   (2) Band 1600-4000 kHz:
   (i) Coast stations and Alaska fixed stations:
   For single sideband and facsimile	20 Hz.
   For narrow-band direct printing and data emissions	10 Hz.1
   For transmitters with digital selective calling emissions	10 Hz.1
   For all other emissions	50 Hz.
   (ii) Ship stations:
   For transmitters with narrow-band direct printing and data emissions	10 Hz.1
   For transmitters with digital selective calling emissions	10 Hz.
   For all other transmitters	20 Hz.
   (iii) Survival craft stations	20 Hz.
   (iv) Radiodetermination stations:
   With power 200W or less	20.
   With power above 200W	10.
   (3) Band 4000-27500 kHz:
   (i) Coast stations and Alaska fixed stations:
   For single sideband and facsimile emissions	20 Hz.
   For narrow-band direct printing and data emissions	10 Hz.1
   For digital selective calling emissions	10 Hz.
   For Morse telegraphy emissions	10.
   For all other emissions	15 Hz.
   (ii) Ship stations:
   For transmitters with narrow-band direct printing and data emissions	10 Hz.1
   For transmitters with digital selective calling emissions	10 Hz.
   For all other transmitters	20 Hz.
   (iii) Survival craft stations	50 Hz.
   (4) Band 72-76 MHz:
   (i) Fixed stations:
   Operating in the 72.0-73.0 and 75.4-76.0 MHz bands	5.
   Operating in the 73.74.6 MHz band	50.
   (5) Band 156-162 MHz:
   (i) Coast stations:
   For carriers licensed to operate with a carrier power:
   Below 3 watts	10.
   3 to 100 watts	5.3
   (ii) Ship stations	10.2
   (iii) Survival craft stations operating on 121.500 MHz	50.
   (iv) EPIRBs:
   Operating on 121.500 and 243.000 MHz	50.
   Operating on 156.750 and 156.800 MHz	10.
   (6) Band 216-220 MHz:
   (i) Coast stations:
   For all emissions	5.
   (ii) Ship stations:
   For all emissions	5.
   (7) Band 400-466 MHz:
   (i) EPIRBs operating on 406-406.1 MHz	5.
   (ii) On-board stations	5.
   (iii) Radiolocation and telecommand stations	5.
   (8) Band 1626.5-1646.5 MHz:
   (i) Ship earth stations	5.
   1 The frequency tolerance for narrow-band direct printing and data transmitters installed before January 2, 1992, is 15 Hz for coast stations and 20 Hz for ship stations. The frequency tolerance for narrow-band direct printing and data transmitters approved or installed after January 1, 1992, is 10 Hz.
   2 For transmitters in the radiolocation and associated telecommand service operating on 154.584 MHz, 159.480 MHz, 160.725 MHz and 160.785 MHz the frequency tolerance is 15 parts in 10.
   3 For transmitters operated at private coast stations with antenna heights less than 6 meters (20 feet) above ground and output power of 25 watts or less the frequency tolerance is 10 parts in 10.

2. (b) When pulse modulation is used in land and ship radar stations operating in the bands above 2.4 GHz the frequency at which maximum emission occurs must be within the authorized bandwidth and must not be closer than 1.5/T MHz to the upper and lower limits of the authorized bandwidth where “T” is the pulse duration in microseconds. In the band 14.00-14.05 GHz the center frequency must not vary more than 10 MHz from 14.025 GHz.
3. (c) For stations in the maritime radiodetermination service, other than ship radar stations, the authorized frequency tolerance will be specified on the license when it is not specified in this part.

[51 FR 31213, Sept. 2, 1986, as amended at 52 FR 7418, Mar. 11, 1987; 53 FR 37308, Sept. 26, 1988; 54 FR 49994, Dec. 4, 1989; 57 FR 26778, June 16, 1992; 58 FR 33344, June 17, 1993; 62 FR 40306, July 28, 1997; 63 FR 36606, July 7, 1998; 68 FR 46964, Aug. 7, 2003; 76 FR 67611, Nov. 2, 2011; 90 FR 57707, Dec. 12, 2025]