§ 90.213   Frequency stability.

   (a) Unless noted elsewhere, transmitters used in the services governed by
   this  part must have a minimum frequency stability as specified in the
   following table.

   Minimum Frequency Stability

   [Parts per million (ppm)]
   Frequency range (MHz) Fixed and base stations Mobile stations
   Over 2 watts output power 2 watts or less output power
   Below 25 ^1 2 3100 100 200
   25-50 20 20 50
   72-76 5 50
   150-174 ^5 115 ^65 ^4 650
   216-220 1.0 1.0
   220-222^12 0.1 1.5 1.5
   421-512 ^7 11 142.5 ^85 ^85
   806-809 ^141.0 1.5 1.5
   809-824 ^141.5 2.5 2.5
   851-854 1.0 1.5 1.5
   854-869 1.5 2.5 2.5
   896-901 ^140.1 1.5 1.5
   902-928 2.5 2.5 2.5
   902-928^13 2.5 2.5 2.5
   929-930 1.5
   935-940 0.1 1.5 1.5
   1427-1435 ^9300 300 300
   Above 2450^10

   ^1Fixed and base stations with over 200 watts transmitter power must have a
   frequency stability of 50 ppm except for equipment used in the Public Safety
   Pool where the frequency stability is 100 ppm.

   ^2For single sideband operations below 25 MHz, the carrier frequency must be
   maintained within 50 Hz of the authorized carrier frequency.

   ^3Travelers information station transmitters operating from 530-1700 kHz and
   transmitters exceeding 200 watts peak envelope power used for disaster
   communications and long distance circuit operations pursuant to § § 90.242 and
   90.264 must maintain the carrier frequency to within 20 Hz of the authorized
   frequency.

   ^4Stations operating in the 154.45 to 154.49 MHz or the 173.2 to 173.4 MHz
   bands must have a frequency stability of 5 ppm.

   ^5In the 150-174 MHz band, fixed and base stations with a 12.5 kHz channel
   bandwidth  must  have a frequency stability of 2.5 ppm. Fixed and base
   stations with a 6.25 kHz channel bandwidth must have a frequency stability
   of 1.0 ppm.

   ^6In the 150-174 MHz band, mobile stations designed to operate with a 12.5
   kHz channel bandwidth or designed to operate on a frequency specifically
   designated for itinerant use or designed for low-power operation of two
   watts or less, must have a frequency stability of 5.0 ppm. Mobile stations
   designed to operate with a 6.25 kHz channel bandwidth must have a frequency
   stability of 2.0 ppm.

   ^7In the 421-512 MHz band, fixed and base stations with a 12.5 kHz channel
   bandwidth  must  have a frequency stability of 1.5 ppm. Fixed and base
   stations with a 6.25 kHz channel bandwidth must have a frequency stability
   of 0.5 ppm.

   ^8In the 421-512 MHz band, mobile stations designed to operate with a 12.5
   kHz channel bandwidth must have a frequency stability of 2.5 ppm. Mobile
   stations designed to operate with a 6.25 kHz channel bandwidth must have a
   frequency stability of 1.0 ppm.

   ^9Fixed stations with output powers above 120 watts and necessary bandwidth
   less than 3 kHz must operate with a frequency stability of 100 ppm. Fixed
   stations with output powers less than 120 watts and using time-division
   multiplex, must operate with a frequency stability of 500 ppm.

   ^10Except for DSRCS equipment in the 5850-5925 MHz band, frequency stability
   is to be specified in the station authorization. Frequency stability for
   DSRCS equipment in the 5850-5925 MHz band is specified in subpart M of this
   part.

   ^11Paging transmitters operating on paging-only frequencies must operate
   with frequency stability of 5 ppm in the 150-174 MHz band and 2.5 ppm in the
   421-512 MHz band.

   ^12Mobile units may utilize synchronizing signals from associated base
   stations to achieve the specified carrier stability.

   ^13Fixed non-multilateration transmitters with an authorized bandwidth that
   is more than 40 kHz from the band edge, intermittently operated hand-held
   readers, and mobile transponders are not subject to frequency tolerance
   restrictions.

   ^14Control stations may operate with the frequency tolerance specified for
   associated mobile frequencies.

   (b) For the purpose of determining the frequency stability limits, the power
   of a transmitter is considered to be the maximum rated output power as
   specified by the manufacturer.

   [ 60 FR 37266 , July 19, 1995, as amended at  61 FR 4235 , Feb. 5, 1996;  61 FR 18986 , Apr. 30, 1996;  61 FR 38403 , July 24, 1996;  62 FR 2040 , Jan. 15, 1997;
    62 FR 18927 , Apr. 17, 1997;  67 FR 41860 , June 20, 2002;  69 FR 46443 , Aug. 3,
   2004;  69 FR 67838 , Nov. 22, 2004]

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