Sec.  73.211   Power and antenna height requirements.

   (a) Minimum requirements. (1) Except as provided in paragraphs (a)(3) and
   (b)(2) of this section, FM stations must operate with a minimum effective
   radiated power (ERP) as follows:

   (i) The minimum ERP for Class A stations is 0.1 kW.

   (ii) The ERP for Class B1 stations must exceed 6 kW.

   (iii) The ERP for Class B stations must exceed 25 kW.

   (iv) The ERP for Class C3 stations must exceed 6 kW.

   (v) The ERP for Class C2 stations must exceed 25 kW.

   (vi) The ERP for Class C1 stations must exceed 50 kW.

   (vii) The minimum ERP for Class C and C0 stations is 100 kW.

   (2) Class C0 stations must have an antenna height above average terrain
   (HAAT) of at least 300 meters (984 feet). Class C stations must have an
   antenna height above average terrain (HAAT) of at least 451 meters (1480
   feet).

   (3) Stations of any class except Class A may have an ERP less than that
   specified in paragraph (a)(1) of this section, provided that the reference
   distance, determined in accordance with paragraph (b)(1)(i) of this section,
   exceeds the distance to the class contour for the next lower class. Class A
   stations may have an ERP less than 100 watts provided that the reference
   distance, determined in accordance with paragraph (b)(1)(i) of this section,
   equals or exceeds 6 kilometers.

   (b) Maximum limits. (1) Except for stations located in Puerto Rico or the
   Virgin  Islands, the maximum ERP in any direction, reference HAAT, and
   distance to the class contour for each FM station class are listed below:
   Station class Maximum ERP Reference HAAT in meters (ft.) Class contour
   distance in kilometers
   A 6 kW (7.8 dBk) 100 (328) 28
   B1 25 kW (14.0 dBk) 100 (328) 39
   B 50 kW (17.0 dBk) 150 (492) 52
   C3 25 kW (14.0 dBk) 100 (328) 39
   C2 50 kW (17.0 dBk) 150 (492) 52
   C1 100 kW (20.0 dBk) 299 (981) 72
   C0 100 kW (20.0 dBk) 450 (1476) 83
   C 100 kW (20.0 dBk) 600 (1968) 92

   (i) The reference distance of a station is obtained by finding the predicted
   distance to the 1mV/m contour using Figure 1 of  Sec. 73.333 and then rounding to
   the nearest kilometer. Antenna HAAT is determined using the procedure in
    Sec. 73.313. If the HAAT so determined is less than 30 meters (100 feet), a HAAT
   of 30 meters must be used when finding the predicted distance to the 1 mV/m
   contour.

   (ii) If a station's ERP is equal to the maximum for its class, its antenna
   HAAT  must  not exceed the reference HAAT, regardless of the reference
   distance. For example, a Class A station operating with 6 kW ERP may have an
   antenna HAAT of 100 meters, but not 101 meters, even though the reference
   distance is 28 km in both cases.

   (iii) Except as provided in paragraph (b)(3) of this section, no station
   will be authorized in Zone I or I-A with an ERP equal to 50 kW and a HAAT
   exceeding 150 meters. No station will be authorized in Zone II with an ERP
   equal to 100 kW and a HAAT exceeding 600 meters.

   (2) If a station has an antenna HAAT greater than the reference HAAT for its
   class, its ERP must be lower than the class maximum such that the reference
   distance does not exceed the class contour distance. If the antenna HAAT is
   so great that the station's ERP must be lower than the minimum ERP for its
   class (specified in paragraphs (a)(1) and (a)(3) of this section), that
   lower ERP will become the minimum for that station.

   (3) For stations located in Puerto Rico or the Virgin Islands, the maximum
   ERP in any direction, reference HAAT, and distance to the class contour for
   each FM station class are listed below:
   Station class Maximum ERP Reference HAAT in meters (ft.) Class contour
   distance in kilometers
   A 6kW (7.8 dBk) 240 (787) 42
   B1 25kW (14.0 dBk) 150 (492) 46
   B 50kW (17.0 dBk) 472 (1549) 78

   (c) Existing stations. Stations authorized prior to March 1, 1984 that do
   not conform to the requirements of this section may continue to operate as
   authorized. Stations operating with facilities in excess of those specified
   in paragraph (b) of this section may not increase their effective radiated
   powers or extend their 1 mV/m field strength contour beyond the location
   permitted by their present authorizations. The provisions of this section
   will not apply to applications to increase facilities for those stations
   operating with less than the minimum power specified in paragraph (a) of
   this section.

   (d) Existing Class C stations below minimum antenna HAAT. Class C stations
   authorized prior to January 19, 2001 that do not meet the minimum antenna
   HAAT specified in paragraph (a)(2) of this section for Class C stations may
   continue to operate as authorized subject to the reclassification procedures
   set forth in Note 4 to  Sec. 73.3573.

   [ 53 FR 17042 , May 13, 1988, as amended at  54 FR 16367 , Apr. 24, 1989;  54 FR 19374 , May 5, 1989;  54 FR 35339 , Aug. 25, 1989;  65 FR 79777 , Dec. 20, 2000]